Isometric force parameters and trunk muscle recruitment strategies in a population with low back pain, Descarreaux M, Lalonde C, Normand MC.

J Manipulative Physiol Ther. 2007 Feb;30(2):91-7.

OBJECTIVE: This study correlates changes in trunk isometric force parameters and trunk muscle recruitment strategies in subjects with low back pain (LBP) and healthy participants. METHODS: A control group study with repeated measures was performed. Study participants included 15 control subjects and 14 patients with LBP. Participants were required to exert 50% and 75% of their maximal trunk flexion and extension. In a learning phase, feedback was provided, after which study participants were asked to perform 10 trials without any feedback. Spatiotemporal parameters of muscular activity and force production were recorded. Dependent variables included time to peak force, peak force variability, absolute error in peak force, electromyogram (EMG) burst duration for agonist muscles, and normalized integrated EMG. RESULTS: Average time to peak force was significantly longer for subjects with LBP than for healthy subjects. Subjects with LBP showed longer burst duration for all 4 muscles recorded. No group difference was noted in normalized integrated EMG. CONCLUSIONS: We suggest that the observed changes in trunk motor control and trunk muscle recruitment strategies are not only mediated by a neurophysiologic adaptation to chronic pain but also by cognitive adaptations modulated by fear of movement and fear of reinjury.

Spinal muscle evaluation in healthy individuals and low-back-pain patients: a literature review, Demoulin C, Crielaard JM, Vanderthommen M.

Joint Bone Spine. 2007 Jan;74(1):9-13. Epub 2006 Nov 13.

Abstract: This article reviews available techniques for spinal muscle investigation, as well as data on spinal muscles in healthy individuals and in patients with low back pain. In patients with chronic low back pain, medical imaging studies show paraspinal muscle wasting with reductions in cross-sectional surface area and fiber density. In healthy individuals, the paraspinal muscles contain a high proportion of slow-twitch fibers (Type I), reflecting their role in maintaining posture. The proportion of Type I fibers is higher in females, leading to better adaptation to aerobic exertion compared to males. Abnormalities seen in paraspinal muscles from patients with chronic low back pain include marked Type II fiber atrophy, conversion of Type I to Type II fibers, and an increased number of nonspecific abnormalities. Limited data are available from magnetic resonance spectroscopy used to investigate muscle metabolism and from near infrared spectroscopy used to measure oxygen uptake by the paraspinal muscles. Surface electromyography in patients with chronic low back pain shows increased paraspinal muscle fatigability, often with abolition of the flexion-relaxation phenomenon.

Comment: This study demonstrates that LBP usually correlates with demonstrable muscle changes that will most likely to produce weakness upon testing.

EMG analysis of shoulder muscle fatigue during resisted isometric shoulder elevation,

Minning S, Eliot CA, Uhl TL, Malone TR.

J Electromyogr Kinesiol. 2006 Mar 16; [Epub ahead of print]

Abstract: The purpose of this study was to determine if a difference existed in the rate of fatigue of select shoulder muscles during isometric shoulder elevation and if the measured rate of fatigue was consistent from day to day. Shoulder muscle fatigue has been associated with alterations in joint mechanics and possibly contributes to shoulder dysfunction. While research exists, there is limited information on an objective and reliable measure of shoulder fatigue. Sixteen asymptomatic subjects were evaluated. The subjects held a weight equivalent to 60% of his/her Maximum Voluntary Isometric Contraction (MVIC) while elevating in the scapular plane. Surface electrodes were applied to collect electromyographic activity from the upper trapezius, middle deltoid, serratus anterior, and lower trapezius muscles while the arm was held at 90 degrees elevation. Data collection ceased when the subject was no longer able to maintain 90 degrees of elevation. The subject then rested and a second trial performed. One week later, the two-trial procedure was repeated. A significant interaction of trialxdayxmuscle was found for the rate of fatigue. Post hoc analysis revealed that the rate of fatigue of the middle deltoid was significantly greater than the other muscles tested. The intraday reliability was good for all muscles but interday reliability was poor except for the middle deltoid. This study suggests that the middle deltoid appears to fatigue faster than the other shoulder muscles tested at the selected level of shoulder elevation. This should be considered in designing a rehabilitation program to develop a sequence that does not overly fatigue the middle deltoid.

Reversible pelvic asymmetry: an overlooked syndrome manifesting as scoliosis, apparent leg-length difference, and neurologic symptoms, Timgren J, Soinila S.

J Manipulative Physiol Ther. 2006 Sep;29(7):561-5.

OBJECTIVE: The objective of this study was to investigate the occurrence of pelvic asymmetry in neurologic patients with symptoms not explained by their neurologic diagnosis. METHODS: We analyzed 150 consecutive neurologic patients referred to physiatric consultation based on their clinical examination findings. RESULTS: We observed pelvic asymmetry associated with either C-type or S-type scoliosis and apparent leg-length difference in 87% of the patients. Symmetry could be reestablished by all patients, although 15% showed immediate or imminent relapse. Maintenance of symmetry showed a highly significant (P < .001) correlation with improvement in functional ability and reduction of pain as evaluated during the last visit to the physiatrist. In the follow-up questionnaire, 78% of the patients reported improvement in functional ability and reduced pain. CONCLUSIONS: Our results support the view that leg-length difference and scoliosis may be more often of reversible nature than previously considered. Acquired postural asymmetry of the sacroiliac joint may be a neglected cause of several neurologic and other pain-related symptoms that can be relieved by a simple and safe treatment.

Effect of Counterstrain on Stretch Reflexes, Hoffmann Reflexes, and Clinical Outcomes in Subjects With Plantar Fasciitis, Wynne MW, Burns JM, Eland DC, Conatser RR, Howell JN.

JAOA Sept 2006;106(9):547-556.

Context: Previous research indicates that osteopathic manipulative treatmentbased on counterstrain produces a decrease in the stretch reflexof the calf muscles in subjects with Achilles tendinitis.Objectives: To study the effects of counterstrain on stretchreflex activity and clinical outcomes in subjects with plantarfasciitis.Methods: In a single-blind, randomized controlled trial of crossover design,the effects of counterstrain were compared with those of placeboin adult subjects (N=20) with plantar fasciitis. The subjectswere led to believe that both the counterstrain and placebowere therapeutic modalities whose effects were being compared.Ten subjects (50%) were assigned to receive 3 weeks of counterstraintreatment during phase 1 of the trial, while the other 10 subjectswere given placebo capsules. After a 2- to 4-week washout period, phase2 of the trial began with the interventions reversed. Clinicaloutcomes were assessed with daily questionnaires. Stretch reflexand H-reflex (Hoffmann reflex) in the calf muscles were assessedtwice during each laboratory visit, before and after treatmentin the counterstrain phase.Results: No significant changes in the electrically recorded reflexesof the calf muscles were observed in response to treatment.However, changes in the mechanical characteristics of the twitchesresulting from the electrical responses were observed. Peakforce and time to reach peak force both increased (P.05) inthe posttreatment measurements, with the increase being significantlymore pronounced in the counterstrain phase (P<.05). A comparisonof pretreatment and posttreatment symptom severity demonstratedsignificant relief of symptoms that was most pronounced immediatelyfollowing treatment and lasted for 48 hours.Conclusions: Clinical improvement occurs in subjects with plantar fasciitisin response to counterstrain treatment. The clinical responseis accompanied by mechanical, but not electrical, changes inthe reflex responses of the calf muscles. The causative relationbetween the mechanical changes and the clinical responses remainsto be explored.

A method for comparing manual muscle strength measurements with joint moments during walking, Fosang A, Baker R.

Gait Posture. 2006 Dec;24(4):406-11. Epub 2006 Jan 18.

Abstract: This paper describes a protocol for dynamometer assisted manual muscle testing of the major muscle groups of the lower extremity and its application to 11 able-bodied children who also had conventional gait analysis to obtain joint kinetics. Data from the manual muscle testing was processed in such a way that the results for maximum muscle strength (grade 5) and resistance against gravity alone (grade 3) were presented in Nm/kg allowing direct comparison with conventional joint kinetics. The strength measurements of the hip muscles and the knee extensors were between two and three times the moments exerted during normal walking. Those of the knee flexors and dorsiflexors were about five times the joint moments. Measured plantarflexor strength was only just greater than the moment exerted during walking. These results, particularly those for the plantarflexors, question how valid it is to use measures of isometric muscle strength as indicators of muscle function during activity. The study also compares grade 3 muscle strength with both grade 5 strength and the maximum joint moments. For all muscle groups tested grade 3 muscle strength was less than the maximum moment exerted during normal walking. For the plantarflexors it was less than 1% of that moment. The study demonstrates that reliable isometric muscle testing is possible in able-bodied children but requires considerable care and is time consuming. More work is required to understand how measurements made in this way relate to how muscles function during activity.

Comment:Many studies have compared the findings of MMT with dynamometer tests favorably, however dynamometers are not as sensitive to changes in strength nor to strength measurements below 3 during the MMT. The human examiner is the most sensitive of all instruments in relationship to interpreting the MMT.

Physiopathology of respiratory muscles, Close P, Dang MN, Bury T.

(Article in French)

Rev Med Liege. 2006 Apr;61(4):227-32.

Abstract: Different factors can have deleterious effect the inspiratory muscles: increased intrinsic mechanical loading of the inspiratory muscles, functional inspiratory muscle weakness, increased ventilatory demand related to capacity...These muscle changes influence exercise tolerance and contribute to dyspnea.

Conservative chiropractic management of recalcitrant foot pain after fasciotomy: a retrospective case review, Wyatt LH.

J Manipulative Physiol Ther. 2006 Jun;29(5):398-402.

OBJECTIVE: The objective of this study was to describe the safety and potential therapeutic benefit of joint mobilization and manipulation in the conservative management of patients with recalcitrant foot pain after plantar fasciotomy. METHODS: The study design was a retrospective review of outcomes of 15 patients seen in a multidisciplinary office setting. All patients had undergone plantar fasciotomy within the 9 months before their admission and had developed lateral foot pain after operation. Each patient had exhibited suboptimal improvement with at least a 4- to 6-week trial of nonsteroidal anti-inflammatory drugs, shoe padding, and rest as prescribed by the attending podiatric surgeon. Manual therapy consisted of either grade III or grade IV joint mobilization and/or high-velocity, low-amplitude chiropractic manipulation to the affected joints in the foot and ankle, and home-based exercise. Outcome criteria were empirically defined as significant improvement, moderate improvement, or no change as assessed by each patient based on a verbal rating scale. RESULTS: There was no long-lasting complication associated with any of the procedures, although a common pattern of transient pain migration over the dorsum of the foot into the ankle was noted in some patients; this resolved by the time of discharge. Of the patients with pain in the calcaneocuboid and/or fifth tarsometatarsal articulation, 11 noted significant improvement, 3 experienced moderate improvement, and 1 reported no change. Patients who complied with home care instructions responded better to therapy in most instances. CONCLUSIONS: These preliminary findings suggest that joint mobilization and manipulation are safe conservative procedures to use in the treatment of patients with lateral column foot pain in status post plantar fasciotomy.

Comment: When muscles fail to support the arch of the foot the ligaments can be stretched, and the medial longitudinal arch of the foot is lost. The many causes of foot pronation, which produces plantar fascitis in many cases, are evaluated in AK including the ligaments, muscles, and joints of the foot and leg.

The effect of chiropractic adjustments on movement time: a pilot study using Fitts Law, Smith DL, Dainoff MJ, Smith JP.

J Manipulative Physiol Ther. 2006 May;29(4):257-66.

OBJECTIVE: To investigate the effect of chiropractic adjustments on movement time using Fitts Law. METHODS: This was a prospective, randomized controlled trial. Ten patients from a private chiropractic practice participated. Participants in the treatment group received high-velocity, low-amplitude chiropractic adjustments to areas of joint dysfunction (chiropractic subluxation). A nonintervention group was used to control for improvement resulting from time and practice effects. Movement time was measured as participants moved a cursor onto a target appearing on a computer screen. A range of target widths and target distances were used to vary the index of difficulty. RESULTS: All participants in the experimental group had significantly improved movement times following spinal adjustments compared with only 1 participant in the control group. The average improvement in movement time for the experimental group was 183 ms, a 9.2% improvement, whereas the average improvement in movement time for the control group was 29 ms, a 1.7% improvement. The difference (improvement) scores after the intervention were significantly greater for the chiropractic group compared with the control group as measured by a 2-tailed independent samples t test (P < .05). CONCLUSION: The results of this study demonstrated a significant improvement in movement time with chiropractic care. These results suggest that spinal adjustments may influence motor behavior.

Comment: Movement time (MT) is an important variable influencing how people control their movements. At the elite sport level even small changes in MT can have a large effect. For instance, differences between the personal best times of the top sprinters in the world in the 100 yard dash can differ by only 1% (i.e. Greene 9.79 seconds, Bailey 9.84 s, and Christie 9.87 s). MT improvement following treatment has been related to Parkinson’s disease severity also. This study demonstrates another investigation into the potential motor control and functional improvements in chiropractic patients.

Improvement in paraspinal muscle tone, autonomic function and quality of life in four children with cerebral palsy undergoing subluxation based chiropractic care: Four retrospective case studies and review of the literature, McCoy M, Malakhova E, Safronov Y, Kent C, Scire P.

J Vertebral Subluxation Research, June 21, 2006:1-15.

Objective: To review the literature and present results experienced by four children with cerebral palsy who underwent chiropractic care to reduce vertebral subluxation. Clinical Features: Four children previously diagnosed with cerebral palsy secondary to birth trauma. All four demonstrated objective evidence of vertebral subluxation. Intervention and Outcomes: Chiropractic care directed at reduction of subluxation was undertaken. Paraspinal surface electromyography and thermography readings were taken prior to the initiation of care and approximately one month (12 visits) later. The mothers and care providers in each case monitored changes in activities of daily living and quality of life. All four children showed improvement in paraspinal muscle tone (improved symmetry and decreased amplitude) as well as a decrease in the number of levels of abnormal thermography readings. All four children showed improvement in activities of daily living including mobility, feeding, and postural control. Conclusion: Improvement in muscle tone and autonomic function coupled with improvement in activities of daily living occurred in these four patients undergoing chiropractic care for reduction of vertebral subluxation. It is suggested that larger studies of this nature be carried out.

The effect of sacroiliac joint manipulation on feed-forward activation times of the deep abdominal musculature,
Marshall P, Murphy B.

J Manipulative Physiol Ther. 2006 Mar-Apr;29(3):196-202.

OBJECTIVES: To determine the incidence of delayed feed-forward activation (FFA) times in a group of healthy young males; to retest those subjects who showed delayed FFA after 6 months to determine the reliability of the measure in the absence of treatment or injury in the intervening period; and to determine the effect of sacroiliac joint manipulation on delayed FFA times. METHODS: Ninety young males were assessed for the FFA of their deep abdominal muscles in relation to rapid upper limb movements. Those who met the criteria for delayed FFA (failure of deep abdominal activation within 50 milliseconds of deltoid activation) were then reassessed 6 months later. These subjects then underwent sacroiliac joint manipulation on the side demonstrating decreased joint movement during hip flexion and lateral flexion. Feed-forward activation times were then reassessed after joint manipulation. RESULTS: Seventeen (18.9%) of 90 subjects met the criteria of impaired FFA. Thirteen of 17 were available to be remeasured at 6-month follow-up. The intraclass correlation coefficient for FFA at this time was greater than 0.70 for all movement directions. There was a significant improvement (38.4%) in FFA times for this group when remeasured immediately after the sacroiliac joint manipulation. CONCLUSIONS: Delayed FFA is a highly reproducible measure at long-term follow-up. This technique appears to be a sensitive marker of the neural effects of sacroiliac joint manipulation. Future prospective studies are needed to determine if delayed FFA times are a marker for those at risk for developing back pain.

Comment: This study demonstrates that an immediately measurable change in muscle function and synergism with other muscles in the body occurs after SI joint manipulation.

Whiplash injury and oculomotor dysfunctions: clinical-posturographic correlations, Storaci R, Manelli A, Schiavone N, Mangia L, Prigione G, Sangiorgi S.

Eur Spine J. 2006 Mar 22

Abstract: Oculomotor dysfunctions are hidden causes of invalidity following whiplash injury. Many patients with whiplash injury grade II present oculomotor dysfunctions related to input disturbances of cervical or vestibular afferents. We used static posturography to investigate 40 consecutive patients with whiplash injury grade II and oculomotor dysfunctions. We demonstrated a relation between length and surface of body sway: the surface value (A) was higher than the length value (L) and this led to an open graph of body sway in the statokinesigram. Oculomotor rehabilitation can resolve the impairment of vestibular function but if therapy is delayed or the patient has been wearing an orthopaedic neck collar, more therapeutic sessions are required. In conclusion, without rehabilitation of the oculomotor muscles other therapies are not sufficient to recover the impairment caused by whiplash injury.

Comment: Patients who have experienced cervical trauma from whiplash dynamics often have perplexing symptoms. The standard orthopedic and neurologic examination often does not find a cause for the bizarre symptoms about which some patients complain. Manual muscle testing is a method for evaluating the function of the nervous system; it often reveals the cause, giving an understanding of the patient's many complaints. Failure to recognize problems in the motor system in whiplash patients, and failure to correct it is often the reason a patient is labeled as being a malingerer or having a psychoneurotic overlay to his condition, and is one of the reasons why symptoms from whiplash injuries can persist for many years. In this report oculomotor dysfunction was present in 62% of the patients affected by whiplash injury. The opening of this paper’s Abstract states the problem: “Oculomotor dysfunctions are hidden causes of invalidity following whiplash injury.” In applied kinesiology chiropractic methodology, a means for testing the integration of the muscles in the body with the visual reflexes has been termed ocular lock.  Ocular lock testing demonstrates the failure of the eyes to work together on a binocular basis through the cardinal fields of gaze.  This is usually not gross pathology of cranial nerves III, IV, and VI; rather it is poor functional organization. The ocular lock phenomenon is theorized to be a consequence, most frequently, to cranial faults.  Diagnosis of the oculomotor function in patients with post-whiplash syndromes has been expedited by AK testing.

Diagnostic accuracy of the neurological upper limb examination I: inter-rater reproducibility of selected findings and patterns, Jepsen JR, Laursen LH, Hagert CG, Kreiner S, Larsen AI.

BMC Neurol. 2006 Feb 16;6:8.

BACKGROUND: We have previously assessed the reproducibility of manual testing of the strength in 14 individual upper limb muscles in patients with or without upper limb complaints. This investigation aimed at additionally studying sensory disturbances, the mechanosensitivity of nerve trunks, and the occurrence of physical findings in patterns which may potentially reflect a peripheral neuropathy. The reproducibility of this part of the neurological examination has never been reported. METHODS: Two blinded examiners performed a semi-quantitative assessment of 82 upper limbs (strength in 14 individual muscles, sensibility in 7 homonymous territories, and mechanosensitivity of nerves at 10 locations). Based on the topography of nerves and their muscular and cutaneous innervation we defined 10 neurological patterns each suggesting a focal neuropathy. The individual findings and patterns identified by the two examiners were compared. RESULTS: Strength, sensibility to touch, pain and vibration, and mechanosensitivity were predominantly assessed with moderate to very good reproducibility (median kappa-values 0.54, 0.69, 0.48, 0.58, and 0.53, respectively). The reproducibility of the defined patterns was fair to excellent (median correlation coefficient = 0.75) and the overall identification of limbs with/without pattern(s) was good (kappa = 0.75). CONCLUSION: This first part of a study on diagnostic accuracy of a selective neurological examination has demonstrated a promising inter-rater reproducibility of individual neurological items and patterns. Generalization and clinical feasibility require further documentation: 1) Reproducibility in cohorts of other composition, 2) validity with comparison to currently applied standards, and 3) potential benefits that can be attained by the examination.

Disorders of breathing and continence have a stronger association with back pain than obesity and physical activity,
Smith MD Russell A, Hodges PW.

Aust J Physiother. 2006;52(1):11-6.

Abstract: Although obesity and physical activity have been argued to predict back pain, these factors are also related to incontinence and breathing difficulties. Breathing and continence mechanisms may interfere with the physiology of spinal control, and may provide a link to back pain. The aim of this study was to establish the association between back pain and disorders of continence and respiration in women. We conducted a cross-sectional analysis of self-report, postal survey data from the Australian Longitudinal Study on Women's Health. We used multinomial logistic regression to model four levels of back pain in relation to both the traditional risk factors of body mass index and activity level, and the potential risk factors of incontinence, breathing difficulties, and allergy. A total of 38,050 women were included from three age-cohorts. When incontinence and breathing difficulties were considered, obesity and physical activity were not consistently associated with back pain. In contrast, odds ratios (OR) for often having back pain were higher for women often having incontinence compared to women without incontinence (OR were 2.5, 2.3 and 2.3 for young, mid-age and older women, respectively). Similarly, mid-aged and older women had higher odds of having back pain often when they experienced breathing difficulties often compared to women with no breathing problems (OR of 2.0 and 1.9, respectively). Unlike obesity and physical activity, disorders of continence and respiration were strongly related to frequent back pain. This relationship may be explained by physiological limitations of co-ordination of postural, respiratory and continence functions of trunk muscles.

Comment: This study confirms a frequent clinical finding in AK, i.e. that problems with respiration involving the phrenic and intercostals nerves affect may produce incontinence in patients. Correction of problems that produce an elevated level of CO₂ in the blood, using AK methods of treatment, can improve the management and outcome of patients with incontinence.

A pilot study comparing the effects of spinal manipulative therapy with those of extra-spinal manipulative therapy on quadriceps muscle strength, Hillermann B, Gomes AN, Korporaal C, Jackson D.

J Manipulative Physiol Ther, 2006 Feb;29(2):145-9.

OBJECTIVE: The objective of this study was to assess whether tibiofemoral joint manipulation is as effective as sacroiliac (SI) joint manipulation in increasing quadriceps muscle strength. DESIGN AND SETTING: Twenty subjects were divided into two groups of 10. After all base measurements of the maximum voluntary force of the quadriceps muscles were taken, subjects in group A received tibiofemoral joint manipulation and those in group B received ipsilateral SI joint manipulation. After these treatments, the maximum voluntary forces of the subjects' quadriceps muscles were retested. RESULTS: A significant improvement (P = .05) in quadriceps muscle strength was noted in the subjects who received an SI joint manipulation. CONCLUSION: This study showed a significant change within the SI joint manipulation group before and after the manipulation but did not show any significant difference between the groups (tibiofemoral joint vs. SI joint manipulation) in increasing quadriceps muscle strength.

Comment: This study demonstrates that an immediately measurable change in muscle strength, from inhibition to strength, occurs after SI joint manipulation. A weakness in this study’s design is that the manipulation of the tibiofemoral joint was a long-axis manipulation of the joint. There was no evaluation done as to whether this joint had any mechanical problem or subluxation present within it. A more specific design would have been to compose group B of subjects who had knee pain in the area of the tibiofemoral joint. Better yet would have been to find subjects for group B who had specific dysfunctions of the tibiofemoral joint. After manipulating the subluxated tibiofemoral joint into proper position, an evaluation of the inhibited quadriceps muscle might have found an improvement in it strength upon testing. In AK, adjustment of the articulations of the knee frequently improves the function of the quadriceps muscle, as does adjustment of the SI joint when it is subluxated.

A prospective randomized controlled trial of spinal manipulation and ultrasound in the treatment of chronic low back pain, Mohammad A, Mohseni-Bandpei, Critchley J, Staunton T, Richardson B

Physiotherapy 92(1) March 2006, Pages 34-42

Objectives. To assess the short- and long-term effectiveness of spinal manipulation therapy, and to identify the effect of manipulation on lumbar muscle endurance in patients with chronic low back pain (LBP). Design. A randomized controlled trial comparing manipulation and exercise treatment with ultrasound and exercise treatment. Setting An outpatient physiotherapy department. Participants One hundred and twenty patients with chronic LBP were allocated at random into the manipulation/exercise group or the ultrasound/exercise group. Interventions Both groups were given a program of exercises. In addition, one group received spinal manipulation therapy and the other group received therapeutic ultrasound. Main outcome measures Pain intensity, functional disability, lumbar movements and muscle endurance were measured shortly before treatment, at the end of the treatment program and 6 months after randomization using surface electromyography. Results Following treatment, the manipulation/exercise group showed a statistically significant improvement (P = 0.001) in pain intensity [mean 16.4 mm, 95% confidence interval (CI) 6.1–26.8], functional disability (mean 8%, 95% CI 2–13) and spinal mobility (flexion: mean 9.4 mm, 95% CI 5.5–13.4; extension: mean 3.4 mm, 95% CI 1.0–5.8). There was no significant difference (P = 0.068) between the two groups in the median frequency of surface electromyography (multifidus: mean 6.8 Hz, 95% CI 1.24–14.91; iliocostalis: mean 2.4 Hz, 95% CI 2.5–7.1), although a significant difference (P = 0.013) was found in the median frequency slope of surface electromyography in favor of spinal manipulation for multifidus alone (mean 0.3, 95% CI 0.1–0.5). A significant difference was also found between the two groups in favor of the manipulation/exercise group at 6-month follow-up. Conclusions Although improvements were recorded in both groups, patients receiving manipulation/exercise showed a greater improvement compared with those receiving ultrasound/exercise at both the end of the treatment period and at 6-month follow-up.

Reliability of techniques to assess human neuromuscular function in vivo, Clark BC, Cook SB, Ploutz-Snyder LL

J Electromyogr Kinesiol. 2006 Jan 18

Abstract: The purpose of this study was to comprehensively evaluate the reliability of a large number of commonly utilized experimental tests of in vivo human neuromuscular function separated by 4-weeks. Numerous electrophysiological parameters (i.e., voluntary and evoked electromyogram [EMG] signals), contractile properties (i.e., evoked forces and rates of force development and relaxation), muscle morphology (i.e., MRI-derived cross-sectional area [CSA]) and performance tasks (i.e., steadiness and time to task failure) were assessed from the plantarflexor muscle group in 17 subjects before and following 4-weeks where they maintained their normal lifestyle. The reliability of the measured variables had wide-ranging levels of consistency, with coefficient of variations (CV) ranging from approximately 2% to 20%, and intraclass correlation coefficients (ICC) between 0.53 and 0.99. Overall, we observed moderate to high-levels of reliability in the vast majority of the variables we assessed (24 out of the 29 had ICC>0.70 and CV<15%). The variables demonstrating the highest reliability were: CSA (ICC=0.93-0.98), strength (ICC=0.97), an index of nerve conduction velocity (ICC=0.95), and H-reflex amplitude (ICC=0.93). Conversely, the variables demonstrating the lowest reliability were: the amplitude of voluntary EMG signal (ICC=0.53-0.88), and the time to task failure of a sustained submaximal contraction (ICC=0.64). Additionally, relatively little systematic bias (calculated through the limits of agreement) was observed in these measures over the repeat sessions. In conclusion, while the reliability differed between the various measures, in general it was rather high even when the testing sessions are separated by a relatively long duration of time.

Evaluation of Apparent and Absolute Supraspinatus Strength in Patients With Shoulder Injury Using the Scapular Retraction Test, Kibler WB, Sciascia A, Dome D.

Am J Sports Med. 2006 May 30; [Epub ahead of print]

BACKGROUND: Physical examination of patients with shoulder injury not involving actual rotator cuff tears frequently demonstrates decreased rotator cuff strength on manual muscle testing. This decrease has been attributed to supraspinatus muscle weakness, but it may be owing to alterations in scapular position. HYPOTHESIS: The position of stabilized scapular retraction, by minimizing proximal kinetic chain factors and providing a stable base of muscle origin, positively influences demonstrated supraspinatus strength. STUDY DESIGN: Controlled laboratory study. METHODS: Supraspinatus strength was tested in 20 injured patients and 10 healthy controls in both the empty-can arm position and a position of scapular retraction using a handheld dynamometer. Pain in both maneuvers was measured by use of a visual analog scale. RESULTS: Paired t tests indicated the scapular retraction position resulted in statistically significantly (P = .001) higher supraspinatus strength values within both groups. There was no significant difference between the 2 positions in visual analog scale scores. CONCLUSION: This study shows that demonstrated apparent supraspinatus weakness on clinical examination in symptomatic patients may be dependent on scapular position. The weakness may be owing to other factors besides supraspinatus muscle weakness, such as a lack of a stable base in the kinetic chain or scapula. CLINICAL RELEVANCE: The clinical examination that addresses scapular posture and includes scapular retraction will allow more accurate determination of absolute supraspinatus muscle strength and allow efficacious rehabilitation protocols to address the source of the demonstrated weakness.

Comment: In AK, precise positioning of the patient is critical to consistently dependable findings in MMT. There are many synergistic muscles to the muscle being primarily evaluated during MMT, and these muscles must be correlated to make final determination of the muscle’s function. Proper muscle testing is the key to an effective examination. Poor or inexact testing may result in misinformation or in the wrong choice of therapies.

The visceromotor responses to colorectal distension and skin pinch are inhibited by simultaneous jejunal distension, Shafton AD, Furness JB, Ferens D, Bogeski G,  Koh SL, Lean NP, Kitchener PD.

Pain. 2006 Jul;123(1-2):127-36. Epub 2006 May 16.

Abstract: Noxious stimuli that are applied to different somatic sites interact; often one stimulus diminishes the sensation elicited from another site. By contrast, inhibitory interactions between visceral stimuli are not well documented. We investigated the interaction between the effects of noxious distension of the colorectum and noxious stimuli applied to the jejunum, in the rat. Colorectal distension elicited a visceromotor reflex, which was quantified using electromyographic (EMG) recordings from the external oblique muscle of the upper abdomen. The same motor units were activated when a strong pinch was applied to the flank skin. Distension of the jejunum did not provoke an EMG response at this site, but when it was applied during colorectal distension it blocked the EMG response. Jejunal distension also inhibited the response to noxious skin pinch. The inhibition of the visceromotor response to colorectal distension was prevented by local application of tetrodotoxin to the jejunum, and was markedly reduced when nicardipine was infused into the local jejunal circulation. Chronic sub-diaphragmatic vagotomy had no effect on the colorectal distension-induced EMG activity or its inhibition by jejunal distension. The nicotinic antagonist hexamethonium suppressed phasic contractile activity in the jejunum, had only a small effect on the inhibition of visceromotor response by jejunal distension. It is concluded that signals that arise from skin pinch and colorectal distension converge in the central nervous system with pathways that are activated by jejunal spinal afferents; the jejunal signals strongly inhibit the abdominal motor activity evoked by noxious stimuli.

Measurement of electrical skin impedance of dermal-visceral zones as a diagnostic tool for inner organ pathologies: a blinded preliminary evaluation of a new technique, Zimlichman E,

Lahad A, Aron-Maor A Kanevsky A, Shoenfeld Y.

Isr Med Assoc J. 2005 Oct;7(10):631-4

BACKGROUND: As complementary and alternative medicine is gaining popularity among health consumers, diagnostic screening tools based on neuroreflexology are also being developed. These techniques, which are based on the rationale that measurement of electrical impedance of specific dermatomes reflects corresponding internal organ pathologies, have not yet been the subject of conventional scientific research. OBJECTIVES: To determine the effectiveness of a neuroreflexology-based screening test, specifically the Medex device (Medex Screen Ltd.), for diagnosing patients undergoing conventional internal organ assessment, in a hospital setting. METHODS: Patients admitted to an internal medicine department, who met the inclusion criteria and agreed to participate, underwent conventional medical evaluation that included past medical history and physical examination. Another examination was conducted by a second physician using the Medex device to determine internal organ pathologies. A third researcher compared the actual "conventional" diagnosis with the Medex device output using standard statistical analysis. RESULTS: Overall, 150 patients participated in the study. Correlation was significant for all categories (P < 0.01) except for blood and lymphatic disease. A high sensitivity (>70%) was measured for cardiovascular, respiratory, gastrointestinal and genitourinary diseases. The highest measure of agreement, as represented by the Cohen-Kappa factor, was found for respiratory disease (0.57). CONCLUSIONS: Although the exact mechanism is not entirely clear, measurement of electroskin impedance of dermal-visceral zones has the potential to serve as a screening tool for inner organ pathologies. Further research should be conducted to create more evidence to support or dispute the use of this technique as a reliable diagnostic tool.

Comment: This study demonstrates a small part of the potentiality of the AK technique called Therapy Localization or TL. In AK, TL is a simple, non-invasive technique to find out where a problem in the body exists. TL doesn’t show the physician what the problem is but shows that something under the hand that is contacting the patient’s body is disturbing the nervous system.

Modulation of intracortical excitability in human hand motor areas. The effect of cutaneous stimulation and its topographical arrangement, Ridding MC, Pearce SL, Flavel SC.

Exp Brain Res. 2005 Jun;163(3):335-43. Epub 2005 Jan 15

Abstract: Changes in afferent input can alter the excitability of intracortical inhibitory systems. For example, using paired transcranial magnetic stimulation (TMS), both electrical digital stimulation and muscle vibration have been shown to reduce short-interval intracortical inhibition (SICI). The effects following muscle vibration are confined to the corticospinal projection to the vibrated muscles. The results following digital stimulation are less clear and the relative timing of the cutaneous stimulation and TMS is critical. Here we investigated further whether changes in SICI following digit stimulation exhibit topographic specificity. Eleven normal subjects were investigated (age 28.2+/-7.5 years, mean+/-SD). Electromyographic recordings were made from the right first dorsal interosseous (FDI), abductor digiti minimi (ADM) and abductor pollicis brevis (APB) muscles. SICI was measured, with and without preceding electrical digit II or digit V cutaneous stimulation. The interval between the digital nerve stimulus and test magnetic stimulus was independently set for each subject and established by subtracting the onset latency of the motor evoked potential (MEP) from the latency of the E2 component of the cutaneomuscular reflex. Therefore, measures of intracortical excitability were made at a time at which it is known that cutaneous input is capable of modulating cortical excitability. Single digital nerve stimuli applied to digit II significantly reduced SICI in FDI but not in ADM. Single digital nerve stimuli applied to digit V significantly reduced SICI in ADM but not in FDI or APB. There was a more generalised effect on intracortical facilitation (ICF) with both digit II and digit V stimulation significantly increasing ICF in FDI and ADM. Digital stimulation (either DII or DV) did not significantly affect SICI/ICF in APB. These findings show that appropriately timed cutaneous stimuli are capable of modulating SICI in a topographically specific manner. We suggest that the selective decrease in SICI seen with cutaneous stimulation may be important for focusing of muscle activation during motor tasks.

Comment: This study demonstrates also a small part of the potentiality of the AK technique called Therapy Localization or TL. The cutaneomuscular reflexes have been extensively investigated in the scientific literature, and they are part of the mechanism for what is found clinically with TL testing.

Delayed trunk muscle reflex responses increase the risk of low back injuries, Cholewicki J, Silfies SP, Shah R, Greene HS, Reeves NP, Alvi K, Goldberg B

Spine. 2005 Dec 1;30(23):2614-20.

STUDY DESIGN: Prospective observational study with a 2- to 3-year follow-up. OBJECTIVES: To determine whether delayed muscle reflex response to sudden trunk loading is a result of or a risk factor for sustaining a low back injury (LBI). SUMMARY OF BACKGROUND DATA: Differences in motor control have been identified in individuals with chronic low back pain and in athletes with a history of LBI when compared with controls. However, it is not known whether these changes are a risk for or a result of LBI. METHODS: Muscle reflex latencies in response to a quick force release in trunk flexion, extension, and lateral bending were measured in 303 college athletes. Information was also obtained regarding their personal data, athletic experience, and history of LBI. The data were entered into a binary logistic regression model to identify the predictors of future LBI. RESULTS: A total of 292 athletes were used for the final analysis (148 females and 144 males). During the follow-up period, 31 (11%) athletes sustained an LBI. The regression model, consisting of history of LBI, body weight, and the latency of muscles shutting off during flexion and lateral bending load releases, predicted correctly 74% of LBI outcomes. The odds of sustaining LBI increased 2.8-fold when a history of LBI was present and increased by 3% with each millisecond of abdominal muscle shut-off latency. On average, this latency was 14 milliseconds longer for athletes who sustained LBI in comparison to athletes who did not sustain LBI (77 [36] vs. 63 [31]). There were no significant changes in any of the muscle response latencies on retest following the injury. CONCLUSIONS: The delayed muscle reflex response significantly increases the odds of sustaining an LBI. These delayed latencies appear to be a preexisting risk factor and not the effect of an LBI.

Trunk muscle recruitment patterns in specific chronic low back pain populations, Silfies SP, Squillante D, Maurer P, Westcott S, Karduna AR.

Clin Biomech (Bristol, Avon). 2005 Jun;20(5):465-73.

BACKGROUND: It is hypothesized that injury or degeneration of osteoligamentous spinal structures would require compensation by trunk musculature and alterations in motor control to maintain spine stability. While, biomechanical modeling has supported this hypothesis, studies of muscle recruitment patterns in chronic low back pain patients both with and without significant osteoligamentous damage have been limited. This study utilized a non-randomized case-control design to investigate trunk muscle recruitment patterns around the neutral spine position between subgroups of patients with chronic mechanical low back pain and asymptomatic controls. METHODS: Twenty subjects with chronic low back pain attributed to clinical lumbar instability were matched to 20 asymptomatic controls. In addition 12 patients with non-specific chronic low back pain were studied. Surface EMG from five trunk muscles was analyzed to determine activation levels and patterns of recruitment during a standing reach under two different loading conditions. FINDINGS: The chronic low back pain group with symptoms attributed to clinical instability demonstrated significantly higher activation levels of the external oblique and rectus abdominus muscles and lower abdominal synergist ratios than the control group. No significant differences were found between patient subgroups. INTERPRETATION: While these data demonstrate altered muscle recruitment patterns in patients with chronic low back pain, the changes are not consistent with Panjabi's theory suggesting that these alterations are driven by passive subsystem damage. However, the higher activation of global abdominal musculature and altered synergist patterns may represent a motor control pattern that has consequences for continued dysfunction and chronic pain.

Comment: In this compendium of evidence for the AK approach to health care there have been more than 20 studies documenting that motor control does not function properly in patients with chronic LBP and neck pain. This type of muscular dysfunction, recognized as critical in patients with LBP and neck pain, involves the disruption of the what Dr. Panjabi terms the stability system of the spine, leading to the suggestion that improper stabilization responses may serve as a perpetuating factor in patients. It would therefore be beneficial for clinicians to have at their disposal simple, reliable, and accurate tests that are capable of detecting the disturbance of these motor control responses and of monitoring the effectiveness of treatment measures designed to correct this dysfunction. AK MMT provides this type of simple, reliable, repeatable physical test.

A model of dynamic sacro–iliac joint instability from malrecruitment of gluteus maximus and biceps femoris muscles resulting in low back pain, Hossain M, Nokes LDM.

Medical Hypotheses, 2005;65(2):278-281.

Effect of gaze direction on neck muscle activity during cervical rotation, Bexander CS, Mellor R, Hodges PW.

Exp Brain Res. 2005 Dec;167(3):422-32. Epub 2005 Sep 29.

Abstract: Control of the neck muscles is coordinated with the sensory organs of vision, hearing and balance. For instance, activity of splenius capitis (SC) is modified with gaze shift. This interaction between eye movement and neck muscle activity is likely to influence the control of neck movement. The aim of this study was to investigate the effect of eye position on neck muscle activity during cervical rotation. In eleven subjects we recorded electromyographic activity (EMG) of muscles that rotate the neck to the right [right obliquus capitis inferior (OI), multifides (MF), and SC, and left sternocleidomastoid (SCM)] with intramuscular or surface electrodes. In sitting, subjects rotated the neck in each direction to specific points in range that were held statically with gaze either fixed to a guide (at three different positions) that moved with the head to maintain a constant intra-orbit eye position or to a panel in front of the subject. Although right SC and left SCM EMG increased with rotation to the right, contrary to anatomical texts, OI EMG increased with both directions and MF EMG did not change from the activity recorded at rest. During neck rotation SCM and MF EMG was less when the eyes were maintained with a constant intra-orbit position that was opposite to the direction of rotation compared to trials in which the eyes were maintained in the same direction as the head movement. The inter-relationship between eye position and neck muscle activity may affect the control of neck posture and movement.

Comment: In applied kinesiology chiropractic methodology, a means for testing the integration of the muscles in the body with the visual reflexes has been termed ocular lock. It demonstrates the failure of the eyes to work together on a binocular basis through the cardinal fields of gaze.  This is usually not gross pathology of cranial nerves III, IV, and VI; rather it is poor functional organization. Mechanical irritation of cranial nerves III, IV, or VI (usually VI) may be responsible for disturbed binocular function leading to discordant sensory inputs from the visual righting reflex. When the eyes are turned in a specific direction, a previously strong indicator muscle will weaken when the ocular lock test is positive. AK evaluation makes the discovery of dysfunction between the movement of the eyes and their coordination with the muscles of the neck possible in the clinical setting.

Myotendinous alterations and effects of resistive loading in old age, Narici M, Maganaris C, Reeves N.

-- Institute for Biophysical and Clinical Research into Human Movement (IRM), Manchester Metropolitan University

Scand J Med Sci Sports. 2005 Dec;15(6):392-401.

Abstract: The loss of muscle mass associated with ageing only partly explains the observed decline in muscle strength. This paper provides evidence of the contribution of muscular, tendinous and neural alterations to muscle weakness in old age and discusses the complex interplay between the changes of the contractile tissue with those of the tendinous tissue in relation to the mechanical behavior of the muscle as a whole. Despite the considerable structural and functional alterations, the elderly musculoskeletal system displays remarkable adaptability to training in old age and many of these adverse effects may be substantially mitigated, if not reversed, by resistive loading. The interplay between these muscular and tendinous adaptations has an impact both on the length-force and force-velocity relationships of the muscle and is likely to affect the range of motion, rate of force development, maximum force development and speed of movement of the older individual.

Erector Spinae and Quadratus Lumborum Muscle Endurance Tests and Supine Leg-Length Alignment Asymmetry: An Observational Study, Knutson, G., Owens, E.

J Manipulative Physiol Ther, 2005;28(8):575-581

Objective: To determine if there is an association between supine leg-length alignment (LLA) asymmetry and the endurance of the erector spinae (ES) and quadratus lumborum (QL) muscles. Methods: Forty-seven subjects (21 women; average age, 36 years old) were tested for ES endurance using the Biering-Sorensen (B-S) test, and 69 (31 women; average age, 34.5 years) were tested for QL endurance. Subjects were examined for supine LLA and tested for ES and QL muscle endurance. The muscle endurance times were compared against those who did and did not demonstrate LLA asymmetry and the side of the “short leg.” Results: In the B-S test, volunteers with LLA asymmetry (n = 27) had a mean endurance time of 89.7 seconds (SD, 43.3), and the no-LLA asymmetry group (n = 20) had a mean endurance time of 161.5 seconds (SD, 57.1), a significant difference (P < .001). In the QL test, after correction for the effects of sex and exercise, those with a right “short leg” (n = 22) had a right QL endurance time of 25.9 seconds (SE, 4.2) and a left QL endurance time of 34.7 seconds (SE, 4.3). The right QL endurance time was significantly different from those subjects with balanced legs (P = .001). Those with a left “short leg” (n = 20) had a left QL endurance time of 28.6 seconds (SE, 4.7) and a right QL endurance time of 38.1 seconds (SE, 4.5). Both QL endurance times were significantly different from those with balanced leg-length (P = .002 and .016, respectively). Conclusion: This study suggests that, using the B-S test, the group of volunteers who demonstrated a commonly used sign of subluxation/joint dysfunction, supine LLA asymmetry, had a decreased endurance times over those who did not. The QL endurance tests showed that the QL muscle ipsilateral to the supine short leg had significantly decreased endurance times over the same-side QL fatigue times in the no leg-length asymmetry group.

Spinal manipulation alters electromyographic activity of paraspinal muscles: a descriptive study, DeVocht J, Pickar J, Wilder D.

J Manipulative Physiol Ther, 2005;28(7):465-471

Objective: To examine the effect of spinal manipulation on electromyographic (EMG) activity in areas of localized tight muscle bundles of the low back.Methods: Surface EMG activity was collected from 16 participants in 2 chiropractic offices during the 5 to 10 minutes of the treatment protocol. Electrodes were placed over the 2 sites of greatest paraspinal muscle tension as determined by manual palpation. Spinal manipulation was administered to 8 participants using Activator protocol; the other 8 were treated using Diversified protocol. Results: Electromyographic activity decreased by at least 25% after treatment in 24 of the 31 sites that were monitored. There was less than 25% change at 3 sites and more than 25% increase at 4 sites. Multiple distinct increases and decreases were observed in many data plots.Conclusion: The results of this study indicate that manipulation induces a virtually immediate change, usually a reduction, in resting EMG levels in at least some patients with low back pain and tight paraspinal muscle bundles. In some cases, EMG activity increased during the treatment protocol and then usually, but not always, decreased to a level lower than the pretreatment level.

A hypothesis of chronic back pain: ligament subfailure injuries lead to muscle control dysfunction, Panjabi M.

Eur Spine J. 2005 Jul 27

Abstract: Clinical reports and research studies have documented the behavior of chronic low back and neck pain patients. A few hypotheses have attempted to explain these varied clinical and research findings. A new hypothesis, based upon the concept that subfailure injuries of ligaments (spinal ligaments, disc annulus and facet capsules) may cause chronic back pain due to muscle control dysfunction, is presented. The hypothesis has the following sequential steps. Single trauma or cumulative microtrauma causes subfailure injuries of the ligaments and embedded mechanoreceptors. The injured mechanoreceptors generate corrupted transducer signals, which lead to corrupted muscle response pattern produced by the neuromuscular control unit. Muscle coordination and individual muscle force characteristics, i.e. onset, magnitude, and shut-off, are disrupted. This results in abnormal stresses and strains in the ligaments, mechanoreceptors and muscles, and excessive loading of the facet joints. Due to inherently poor healing of spinal ligaments, accelerated degeneration of disc and facet joints may occur. The abnormal conditions may persist, and, over time, may lead to chronic back pain via inflammation of neural tissues. The hypothesis explains many of the clinical observations and research findings about the back pain patients. The hypothesis may help in a better understanding of chronic low back and neck pain patients, and in improved clinical management.

Comment: This is one of the most important articles published to date on the musculoskeletal aspects of the subluxation. Dr. Panjabi is the world’s most published human biomechanical researcher, with 263 published articles to date. The hypothesis he presents in this paper places the functionality of muscles, as both a cause and a consequence of mechanoreceptor dysfunction in chronic back pain patients, at the center of a sequence of events that ultimately results in back pain. As a result of spinal subluxations, muscle coordination and individual muscle force characteristics, i.e. inhibited muscles on MMT, are disrupted. The injured mechanoreceptors generate corrupted transducer signals (that could be detected by EMG, dynamometers, or MMT), which lead to corrupted muscle response patterns produced by the neuromuscular control unit.  This article is very important for those in the chiropractic profession who are evaluating the existence and the consequences of the subluxation. The key technical factor that makes AK indispensable in the detection of spinal dysfunction is the MMT that makes the detection of muscular imbalance verifiable.

Parallel comparison of grip strength measures obtained with a MicroFET 4 and a Jamar dynamometer, Bohannon RW.

-- Department of Physical Therapy, School of Allied Health, U-2101, University of Connecticut, Storrs, CT 06269-2101, USA.

Percept Mot Skills. 2005 Jun;100(3 Pt 1):795-8.

Abstract:Repeated measures of grip strength obtained bilaterally with a Jamar and a MicroFET 4 dynamometer were compared. Measurements obtained with the MicroFET 4 tended to be slightly (2.2-3.1 lb.) higher but were highly correlated (r > or = .96) with those obtained with the Jamar. Parallel reliability for the two devices was excellent (intraclass correlation coefficient > or = .96). Although clinicians should be cautious about using the devices interchangeably, the MicroFET 4 appears to be a legitimate alternative to the Jamar dynamometer.

Quantifying shoulder rotation weakness in patients with shoulder impingement, Tyler TF, Nahow RC, Nicholas SJ, McHugh MP.

-- Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York, NY, USA; PRO Sports Physical Therapy of Westchester, New York, NY, USA.

J Shoulder Elbow Surg. 2005 Nov-Dec;14(6):570-4.

Abstract: The purpose of this study was to determine whether strength deficits could be detected in individuals with and without shoulder impingement, all of whom had normal shoulder strength bilaterally according to grading of manual muscle testing. Strength of the internal rotators and external rotators was tested isokinetically at 60 degrees /s and 180 degrees /s, as well as manually with a handheld dynamometer (HHD) in 17 patients and 22 control subjects. Testing was performed with the shoulder positioned in the scapular plane and in 90 degrees of shoulder abduction with 90 degrees of elbow flexion (90-90). The peak torque was determined for each movement. The strength deficit between the involved and uninvolved arms (patients) and the dominant and nondominant arms (control subjects) was calculated for each subject. Comparisons were made for the scapular-plane and 90-90 positions between isokinetic and HHD testing. Despite a normal muscle grade, patients had marked weakness (28% deficit, P < .01) in external rotators at the 90-90 position tested with the HHD. In contrast, external rotator weakness was not evident with isokinetic testing at the 90-90 position (60 degrees /s and 180 degrees /s, 0% deficit, P = .99). In control subjects, greater internal rotator strength in the dominant compared with the nondominant arm was evident with the HHD at the 90-90 position (11%, P < .01) and in the scapular plane (7%, P < .05). Using an HHD while performing manual muscle testing can quantify shoulder strength deficits that may not be apparent with isokinetic testing. By using an HHD during shoulder testing, clinicians can identify weakness that may have been presumed normal.

Scapular muscle tests in subjects with shoulder pain and functional loss: reliability and construct validity, Michener LA, Boardman ND, Pidcoe PE, Frith AM.

Phys Ther. 2005 Nov;85(11):1128-38.

BACKGROUND AND PURPOSE: Scapular muscle performance evaluated with a handheld dynamometer (HHD) has been investigated only in people without shoulder dysfunction for test-retest reliability of data obtained with a single scapular muscle test. The purpose of this study was to assess the reliability, error, and validity of data obtained with an HHD for 4 scapular muscle tests in subjects with shoulder pain and functional loss. SUBJECTS AND METHODS: Subjects (N=40) with shoulder pain and functional loss were tested by measuring the kilograms applied with an HHD during 3 trials for muscle tests for the lower trapezius, upper trapezius, middle trapezius, and serratus anterior muscles. Concurrently, surface electromyography (sEMG) data were collected for the 4 muscles. The same procedures were performed 24 to 72 hours after the initial testing by the same tester. Muscle tests were performed 3 times, and the results were averaged for data analysis. RESULTS: Intraclass correlation coefficients for intratester reliability of measurements of isometric force obtained using an HHD ranged from .89 to .96. The standard error of the measure (90% confidence interval [CI]) ranged from 1.3 to 2.7 kg; the minimal detectable change (90% CI) ranged from 1.8 to 3.6 kg. Construct validity assessment, done by comparing the amounts of isometric muscle activity (sEMG) for each muscle across the 4 muscle tests, revealed that the muscle activity of the upper trapezius and lower trapezius muscles was highest during their respective tests. Conversely, the isometric muscle activity of the middle trapezius and serratus anterior muscles was not highest during their respective tests. DISCUSSION AND CONCLUSION: In people with shoulder pain and functional loss, the intrarater reliability and error over 1 to 3 days were established using an HHD for measurement of isometric force for the assessment of scapular muscle performance. Error values can be used to make decisions regarding individual patients. Construct validity was established for the lower and upper trapezius muscle tests; therefore, these tests are advocated for use. However, construct validity was not demonstrated for the serratus anterior and middle trapezius muscle tests as performed in this study. Further investigation of these muscle tests is warranted.

Comment: The correlation between MMT and HHD findings has been established in much of the research literature. This paper shows that there is a construct validity and reliability to employing MMT and HHD testing in patients with shoulder injuries.

Hip muscle weakness and overuse injuries in recreational runners, Niemuth PE, Johnson RJ, Myers MJ, Thieman TJ.

Clin J Sport Med. 2005 Jan;15(1):14-21.

OBJECTIVE: To test for differences in strength of 6 muscle groups of the hip on the involved leg in recreational runners with injuries compared with the uninvolved leg and a control group of noninjured runners. DESIGN: Descriptive analysis. SETTING: Three outpatient physical therapy clinics in the Minneapolis/St. Paul metropolitan area. PARTICIPANTS: Thirty recreational runners (17 female, 13 male) experiencing a single leg overuse injury that presented for treatment between June and September 2002. Thirty noninjured runners (16 female, 14 male) randomly selected from a pool of 46 volunteers from a distance running club served as controls. MAIN OUTCOME MEASURES: Self-report demographic information on running habits, leg dominance demonstrated by preferred kicking leg, and injury information. Muscle strength of the 6 major muscle groups of the hip was recorded using a hand-held dynamometer. The highest value of 2 trials was used, and strength values were normalized to body mass(2/3). RESULTS: Results comparing the injured and noninjured groups showed that leg dominance did not influence the leg of injury (chi(2)(1) = 0.134; P = 0.71). Correlations for internal reliability of muscle measurements between trials 1 and 2 with the hand-held dynamometer ranged from 0.80 to 0.90 for the 6 muscle groups measured, and all P values were less than 0.0001. No significant side-to-side differences in hip group muscle strength were found in the noninjured runners (P = 0.62-0.93). Among the injured runners, the injured side hip abductor (P = 0.0003) and flexor muscle groups (P = 0.026) were significantly weaker than the noninjured side. In addition, the injured side hip adductor muscle group was significantly stronger (P = 0.010) than the noninjured side. Duration of symptoms was not a contributing factor to the extent of injury as measured by muscle strength imbalance between injured and uninjured sides. CONCLUSIONS: Although no cause-and-effect relationship has been established, this is the first study to show an association between hip abductor, adductor, and flexor muscle group strength imbalance and lower extremity overuse injuries in runners. Because most running injuries are multifaceted in nature, areas secondary to the site of pain, such as hip muscle groups exhibiting strength imbalances, must also be considered to gain favorable outcomes for injured runners. The addition of strengthening exercises to specifically identified weak hip muscles may offer better treatment results in patients with running injuries.

Comment: This study shows an important evidence-based component of the treatment of hip and pelvic problems in runners as being methods of strengthening the weak muscles around the hip and to improve muscular balance, the sine qua non of AK treatment.

Long-term follow-up of a randomized clinical trial assessing the efficacy of medication, acupuncture, and spinal manipulation for chronic mechanical spinal pain syndromes, Muller R, Giles LG.

J Manipulative Physiol Ther. 2005 Jan;28(1):3-11.

OBJECTIVE: To assess the long-term benefits of medication, needle acupuncture, and spinal manipulation as exclusive and standardized treatment regimens in patients with chronic (>13 weeks) spinal pain syndromes. STUDY DESIGN: Extended follow-up (>1 year) of a randomized clinical trial was conducted at the multidisciplinary spinal pain unit of Townsville's General Hospital between February 1999 and October 2001. PATIENTS AND METHODS: Of the 115 patients originally randomized, 69 had exclusively been treated with the randomly allocated treatment during the 9-week treatment period (results at 9 weeks were reported earlier). These patients were followed up and assessed again 1 year after inception into the study reapplying the same instruments (i.e., Oswestry Back Pain Index, Neck Disability Index, Short-Form-36, and Visual Analogue Scales). Questionnaires were obtained from 62 patients reflecting a retention proportion of 90%. The main analysis was restricted to 40 patients who had received exclusively the randomly allocated treatment for the whole observation period since randomization. RESULTS: Comparisons of initial and extended follow-up questionnaires to assess absolute efficacy showed that only the application of spinal manipulation revealed broad-based long-term benefit: 5 of the 7 main outcome measures showed significant improvements compared with only 1 item in each of the acupuncture and the medication groups. CONCLUSIONS: In patients with chronic spinal pain syndromes, spinal manipulation, if not contraindicated, may be the only treatment modality of the assessed regimens that provides broad and significant long-term benefit.

Muscle reflex classification of low-back pain, Reeves NP, Cholewicki J, Milner TE.

J Electromyogr Kinesiol. 2005 Feb;15(1):53-60. Epub 2004 Nov 21.

Abstract: It has been well documented that low-back pain (LBP) patients have longer muscle response latencies to perturbation than healthy controls. These muscle responses appear to be reflexive and not voluntary in nature, and as a result, might be useful for objectively classifying LBP. The goal of the study was to develop an objective and accurate method for classifying LBP using a sudden load-release protocol. Subjects were divided into two groups: learning group (20 patients and 20 controls), and holdout group (15 patients and 12 controls). Subjects exerted isometric trunk force against a cable in four different directions. Following cable release, the trunk was suddenly displaced eliciting a muscle reflex response. Reflex latencies for muscles switching-on and shutting-off were determined using electromyogram signals from 8 trunk muscles. Independent t tests were performed on the learning group to determine which reflex parameters were to be entered into logistic regression analysis to produce a classification model. The holdout group was used to validate this classification model. The three-parameter model was able to correctly classify 83% of the learning group, and 81% of the holdout group. Using reflex parameters appears to be an accurate and objective method for classifying LBP.

Motor unit synchronization is reduced in anterior knee pain,
Mellor R, Hodges PW.

J Pain. 2005 Aug;6(8):550-8.

Abstract: Anterior knee pain (AKP) is common and has been argued to be related to poor patellofemoral joint control due to impaired coordination of the vasti muscles. However, there are conflicting data. Changes in motor unit firing may provide more definitive evidence. Synchronization of motor unit action potentials (MUAPs) in vastus medialis obliquus (VMO) and vastus lateralis (VL) may contribute to coordination in patellofemoral joint control. We hypothesized that synchronization may be reduced in AKP. Recordings of single MUAPs were made from VMO and multiunit electromyograph (EMG) recordings were made from VL. Averages of VL EMG recordings were triggered from the single MUAPs in VMO. Motor units in VL firing in association with the VMO motor units would appear as a peak in the VL EMG average. Data were compared to previous normative data. The proportion of trials in which a peak was identified in the triggered averages of VL EMG was reduced in people with AKP (38%) compared to controls (90%). Notably, although 80% of subjects had values less than controls, 20% were within normal limits. These results provide new evidence that motor unit synchronization is modified in the presence of pain and provide evidence for motor control dysfunction in AKP. PERSPECTIVE: This study shows that coordination of motor units between the medial and lateral vasti muscles in people with anterior knee pain is reduced compared to people without knee pain. It confirms that motor control dysfunction is a factor in this condition and has implications for selection of rehabilitation strategies.

Comment: This study suggests that in some cases, correcting knee pain is often as simple as correcting the muscles that stabilize the knee. AK evaluation of knee dysfunction always involves testing the knee-supporting muscles’ function.

Chronic spinal pain: a randomized clinical trial comparing medication, acupuncture, and spinal manipulation, Giles LG, Muller R.

Spine. 2005 Jan 1;30(1):166.

STUDY DESIGN: A randomized controlled clinical trial was conducted. OBJECTIVE: To compare medication, needle acupuncture, and spinal manipulation for managing chronic (>13 weeks duration) spinal pain because the value of medicinal and popular forms of alternative care for chronic spinal pain syndromes is uncertain. SUMMARY OF BACKGROUND DATA: Between February 1999 and October 2001, 115 patients without contraindication for the three treatment regimens were enrolled at the public hospital's multidisciplinary spinal pain unit. METHODS: One of three separate intervention protocols was used: medication, needle acupuncture, or chiropractic spinal manipulation. Patients were assessed before treatment by a sports medical physician for exclusion criteria and by a research assistant using the Oswestry Back Pain Disability Index (Oswestry), the Neck Disability Index (NDI), the Short-Form-36 Health Survey questionnaire (SF-36), visual analog scales (VAS) of pain intensity and ranges of movement. These instruments were administered again at 2, 5, and 9 weeks after the beginning of treatment. RESULTS: Randomization proved to be successful. The highest proportion of early (asymptomatic status) recovery was found for manipulation (27.3%), followed by acupuncture (9.4%) and medication (5%). Manipulation achieved the best overall results, with improvements of 50% (P = 0.01) on the Oswestry scale, 38% (P = 0.08) on the NDI, 47% (P < 0.001) on the SF-36, and 50% (P < 0.01) on the VAS for back pain, 38% (P < 0.001) for lumbar standing flexion, 20% (P < 0.001) for lumbar sitting flexion, 25% (P = 0.1) for cervical sitting flexion, and 18% (P = 0.02) for cervical sitting extension. However, on the VAS for neck pain, acupuncture showed a better result than manipulation (50% vs. 42%). CONCLUSIONS: The consistency of the results provides, despite some discussed shortcomings of this study, evidence that in patients with chronic spinal pain, manipulation, if not contraindicated, results in greater short-term improvement than acupuncture or medication. However, the data do not strongly support the use of only manipulation, only acupuncture, or only nonsteroidal anti-inflammatory drugs for the treatment of chronic spinal pain. The results from this exploratory study need confirmation from future larger studies.

Navigating a sensorimotor loop, Fanselow EE, Connors BW.

Neuron. 2005 Feb 3;45(3):329-30.

Abstract: Touch is an active process, but how do the body's somatic sensors influence its movement? In this issue of Neuron, Nguyen and Kleinfeld show that afferent activity from the whiskers on a rat's face trigger rapid and prolonged excitation of the motor neurons that drive movements of the same whiskers. Positive feedback through this sensorimotor loop may serve to optimize the interaction between sensors and stimuli.

Comment:This study demonstrates that there exists a sensori-motor loop that may be responsible for changes in muscle strength after tactile stimulation. This paper shows a small part of the potentiality of the AK technique called Therapy Localization or TL. The cutaneomuscular reflexes have been extensively investigated in the scientific literature, and they may be a part of the mechanism for what is found clinically with TL testing.

Evidence for strong synaptic coupling between single tactile afferents from the sole of the foot and motoneurons supplying leg muscles, Fallon JB Bent LR, McNulty PA, Macefield VG.

J Neurophysiol. 2005 Dec;94(6):3795-804. Epub 2005 Aug 3.

Abstract: It has been known for some time that populations of cutaneous and muscle afferents can provide short-latency facilitation of motoneuron pools. Recently, it has been shown that the input from individual low-threshold mechanoreceptors in the glabrous skin of the hand can modulate ongoing activity in muscles acting on the fingers via spinally mediated pathways. We have extended this work to examine whether such strong synaptic coupling exists between tactile afferents in the sole of the foot and motoneurons supplying muscles that act about the ankle. We recorded from 53 low-threshold mechanoreceptors in the glabrous skin of the foot via microelectrodes inserted percutaneously into the tibial nerve of awake human subjects. Reflex modulation of ongoing whole muscle electromyography (EMG) was observed for each of the four classes of low-threshold cutaneous mechanoreceptors (17 of 21 rapidly adapting type I; 2 of 4 rapidly adapting type II; 7 of 18 slowly adapting type I; and 4 of 10 slowly adapting type II). Reflex modulation of the firing probability in single motor units (5 of 11) was also observed. These results indicate that strong synaptic coupling between tactile afferents and spinal motoneurons is not a specialization of the hand and emphasizes the potential importance of cutaneous inputs from the sole of the foot in the control of gait and posture.

Comment:This study demonstrates that stimulation of the skin may be responsible for changes in muscle strength. This paper shows a small part of the potentiality of the AK technique called Therapy Localization or TL. The cutaneomuscular reflexes have been extensively investigated in the scientific literature, and they may be a part of the mechanism for what is found clinically with TL testing.

Measurement of electrical skin impedance of dermal-visceral zones as a diagnostic tool for inner organ pathologies: a blinded preliminary evaluation of a new technique, Zimlichman E, Lahad A, Aron-Maor A, Kanevsky A, Shoenfeld Y.

Isr Med Assoc J. 2005 Oct;7(10):631-4.

BACKGROUND: As complementary and alternative medicine is gaining popularity among health consumers, diagnostic screening tools based on neuroreflexology are also being developed. These techniques, which are based on the rationale that measurement of electrical impedance of specific dermatomes reflects corresponding internal organ pathologies, have not yet been the subject of conventional scientific research. OBJECTIVES: To determine the effectiveness of a neuroreflexology-based screening test, specifically the Medex device (Medex Screen Ltd.), for diagnosing patients undergoing conventional internal organ assessment, in a hospital setting. METHODS: Patients admitted to an internal medicine department, who met the inclusion criteria and agreed to participate, underwent conventional medical evaluation that included past medical history and physical examination. Another examination was conducted by a second physician using the Medex device to determine internal organ pathologies. A third researcher compared the actual "conventional" diagnosis with the Medex device output using standard statistical analysis. RESULTS: Overall, 150 patients participated in the study. Correlation was significant for all categories (P < 0.01) except for blood and lymphatic disease. A high sensitivity (>70%) was measured for cardiovascular, respiratory, gastrointestinal and genitourinary diseases. The highest measure of agreement, as represented by the Cohen-Kappa factor, was found for respiratory disease (0.57). CONCLUSIONS: Although the exact mechanism is not entirely clear, measurement of electroskin impedance of dermal-visceral zones has the potential to serve as a screening tool for inner organ pathologies. Further research should be conducted to create more evidence to support or dispute the use of this technique as a reliable diagnostic tool.

Comment:This study demonstrates that the electrodermal reflexes of the skin may be reflective of internal organ pathologies. The cutaneomuscular reflexes have been extensively investigated in the scientific literature, and new research is now showing that electro-dermal impedance measurements of the skin may serve as a screening tool for inner organ pathologies. The significance of these findings to the AK concepts of therapy localization may be evident to the reader.

Neck flexor muscle fatigue is side specific in patients with unilateral neck pain, Falla D, Jull G, Rainoldi A, Merletti R.

Eur J Pain. 2004 Feb;8(1):71-7.

Abstract: Despite the evidence of greater fatigability of the cervical flexor muscles in neck pain patients, the effect of unilaterality of neck pain on muscle fatigue has not been investigated. This study compared myoelectric manifestations of sternocleidomastoid (SCM) and anterior scalene (AS) muscle fatigue between the painful and non-painful sides in patients with chronic unilateral neck pain. Myoelectric signals were recorded from the sternal head of SCM and the AS muscles bilaterally during sub-maximal isometric cervical flexion contractions at 25% and 50% of the maximum voluntary contraction (MVC). The time course of the mean power frequency, average rectified value and conduction velocity of the electromyographic signals were calculated to quantify myoelectric manifestations of muscle fatigue. Results revealed greater estimates of the initial value and slope of the mean frequency for both the SCM and AS muscles on the side of the patient's neck pain at 25% and 50% of MVC. These results indicate greater myoelectric manifestations of muscle fatigue of the superficial cervical flexor muscles ipsilateral to the side of pain. This suggests a specificity of the effect of pain on muscle function and hence the need for specificity of therapeutic exercise in the management of neck pain patients.

Impairment in the cervical flexors: a comparison of whiplash and insidious onset neck pain patients, Jull G,

Kristjansson E, Dall'Alba P.

Man Ther. 2004 May;9(2):89-94.

Abstract: There has been little investigation into whether or not differences exist in the nature of physical impairment associated with neck pain of whiplash and insidious origin. This study examined the neck flexor synergy during performance of the cranio-cervical flexion test, a test targeting the action of the deep neck flexors. Seventy-five volunteer subjects participated in this study and were equally divided between Group 1, asymptomatic control subjects, Group 2, subjects with insidious onset neck pain and Group 3, subjects with neck pain following a whiplash injury. The cranio-cervical flexion test was performed in five progressive stages of increasing cranio-cervical flexion range. Subjects' performance was guided by feedback from a pressure sensor inserted behind the neck which monitored the slight flattening of the cervical lordosis which occurs with the contraction of longus colli. Myoelectric signals (EMG) were detected from the muscles during performance of the test. The results indicated that both the insidious onset neck pain and whiplash groups had higher measures of EMG signal amplitude (normalized root mean square) in the sternocleidomastoid during each stage of the test compared to the control subjects (all P<0.05) and had significantly greater shortfalls from the pressure targets in the test stages (P<0.05). No significant differences were evident between the neck pain groups in either parameter indicating that this physical impairment in the neck flexor synergy is common to neck pain of both whiplash and insidious origin.

Chronic back pain is associated with decreased prefrontal and thalamic gray matter density, Apkarian AV, Sosa Y, Sonty S, Levy RM, Harden RN, Parrish TB, Gitelman DR

J Neurosci. 2004 Nov 17;24(46):10410-5.

Abstract: The role of the brain in chronic pain conditions remains speculative. We compared brain morphology of 26 chronic back pain (CBP) patients to matched control subjects, using magnetic resonance imaging brain scan data and automated analysis techniques. CBP patients were divided into neuropathic, exhibiting pain because of sciatic nerve damage, and non-neuropathic groups. Pain-related characteristics were correlated to morphometric measures. Neocortical gray matter volume was compared after skull normalization. Patients with CBP showed 5-11% less neocortical gray matter volume than control subjects. The magnitude of this decrease is equivalent to the gray matter volume lost in 10-20 years of normal aging. The decreased volume was related to pain duration, indicating a 1.3 cm3 loss of gray matter for every year of chronic pain. Regional gray matter density in 17 CBP patients was compared with matched controls using voxel-based morphometry and nonparametric statistics. Gray matter density was reduced in bilateral dorsolateral prefrontal cortex and right thalamus and was strongly related to pain characteristics in a pattern distinct for neuropathic and non-neuropathic CBP. Our results imply that CBP is accompanied by brain atrophy and suggest that the pathophysiology of chronic pain includes thalamocortical processes.

Comment: The relationship between spinal malfunction and cerebral malfunction, specifically greatly accelerated atrophy of the brain, is an important concept for the chiropractic profession. This is especially important in light of the research articles that document that chiropractic spinal adjustments are more effective in treating chronic spinal pain when compared to medication, exercise, and needle acupuncture.

Hypothyroidism: A New Model for Conservative Management in Two Cases, Bablis, P. and Pollard, H.

Chiro J Aust, 2004;34:11-18

Objective:To review the function, anatomy, physiology, development, hormone synthesis and dysfunction of the thyroid gland. Treatment options are discussed, and 2 case studies of a mind-body therapy (Neuro-Emotional Technique—NET) successfully managing hypothyroid dysfunction are presented. Data Sources: MEDLINE search using key words: thyroid, synthesis, development, anatomy, physiology, hyperthyroidism and hypothyroidism. Data Selection: Eighty-five papers fit the key words and were selected based on relevance to the topic. Papers were selected that contained relevant information on normal andabnormal thyroid function and its management. Data Extraction: Selected papers had to contain information that directly related to the diagnosis, anatomy, physiology and management of hypothyroid conditions. Papers were also selected that described a possible neurophysiological mechanism for the observed treatment effects. Data Synthesis:Objective measures of a new mind-body approach to hypothyroid dysfunction are presented, and its relevance to the biopsychosocial model is discussed. This new treatment is compared to the existing biomedical approaches to treatment. Conclusion: Thyroid dysfunction has been effectively treated with medicine for many years. This paper presents a new therapy that produced objective pre-post changes to hypothyroid dysfunction in 2 cases. This therapy may have potential in future circumstances, with further research recommended to confirm its reliability/validity.

Reliability of hand-held dynamometry in assessment of knee extensor strength after hip fracture, Roy, MA, Doherty, TJ.

-- School of Kinesiology, University of Western Ontario, London, Ontario, Canada.

Am J Phys Med Rehabil. 2004 Nov;83(11):813-8.

OBJECTIVES:To examine the reliability of hand-held dynamometry in assessing knee extensor strength in inpatients undergoing rehabilitation after hip fracture and to examine the discriminant validity of this measure.  DESIGN: A total of 16 subjects (14 women; mean +/- SD, 79 +/- 7 yrs) undergoing inpatient rehabilitation after hip fracture volunteered to participate. Isometric knee extensor strength of the fractured and unfractured sides was determined with a hand-held dynamometer. Subjects were retested 1-2 days after the initial testing session.  RESULTS: Test-retest intraclass correlation coefficients were high for both the fractured (0.91) and unfractured legs (0.90). A low coefficient of variation was observed for both the fractured (15.3%) and unfractured (14.7%) sides. The maximal knee extensor strength was significantly different when comparing the fractured (7.9 +/- 3 kg) and unfractured (15.6 +/- 4 kg) legs. When comparing test 1 and test 2 mean values for the fractured leg, the scores significantly differed (t = 3.14, P < 0.01), with 13 of 16 subjects scoring higher on test 2.  CONCLUSIONS: Hand-held dynamometry is a reliable and valid tool for assessment of knee extensor strength after hip fracture. Reduced knee extensor strength in the fractured leg may be an important component limiting rehabilitation progress in these patients.

Differences in motor recruitment and resulting kinematics between low back pain patients and asymptomatic participants during lifting exertions, Ferguson SA, Marras WS, Burr DL, Davis KG, Gupta P.

Clin Biomech (Bristol, Avon). 2004 Dec;19(10):992-9.

BACKGROUND: Low back disorders are a prevalent problem in society today and may lead to chronic debilitating low back pain. Developing our understanding of temporal muscle and kinematic patterns during manual material handling tasks may provide insight for preventing the cascading series of events leading to chronic low back pain. METHODS: Sixty-two low back pain patients and 61 asymptomatic participants performed a variety of lifting exertions that varied in lift origin horizontal and vertical distance, lift asymmetry, and weight. Electromyographic activity of 10 trunk muscles as well as trunk and pelvic kinematics was recorded during each exertion. Differences in muscle activation and kinematic parameters were compared between low back pain patients and asymptomatic participants as a function of experimental conditions. FINDINGS: Both the left and right erector spinae activated significantly earlier and were on significantly longer in low back pain patients compared to asymptomatic participants. The horizontal and vertical location of the lift influenced the EMG and kinematic differences between the low back pain patients and asymptomatic participants. INTERPRETATION: These finding indicate that low back pain patients would be exposed to increase muscle activity resulting in higher spine loads for a greater length of time compared to asymptomatic participants. The longer exposure time to increased spine load may lead to greater risk of future low back injury and cascading events leading to debilitating low back pain. The longer muscle activation time suggests that low back pain patients have changed their motor program from an open to a closed loop system.

Changes in recruitment of the abdominal muscles in people with low back pain: ultrasound measurement of muscle activity, Ferreira PH, Ferreira ML, Hodges PW.

Spine. 2004 Nov 15;29(22):2560-6.

STUDY DESIGN: Ultrasound and electromyographic (EMG) measures of trunk muscle activity were compared between low back pain (LBP) and control subjects in a cross-sectional study. OBJECTIVES: To compare the recruitment of the abdominal muscles (measured as a change in thickness with ultrasound imaging) between people with and without low back pain and to compare these measurements with EMG recordings made with intramuscular electrodes. SUMMARY OF BACKGROUND DATA: Although ultrasonography has been advocated as a noninvasive measure of abdominal muscle activity, it is not known whether it can provide a valid measure of changes in motor control of the abdominal muscles in LBP. METHODS: Ten subjects with recurrent LBP and 10 matched controls were tested during isometric low load tasks with their limbs suspended. Changes in thickness from resting baseline values were obtained for transversus abdominis (TrA), obliquus internus (OI), and obliquus externus (OE) using ultrasonography. Fine wire EMG was measured concurrently. RESULTS: Study participants with LBP had a significantly smaller increase in TrA thickness with isometric leg tasks compared with controls. No difference was found between groups for OI or OE. Similar results were found for EMG. People with LBP had less TrA EMG activity with leg tasks, and there was no difference between groups for EMG activity for OI or OE. CONCLUSIONS: This study reinforces evidence for changes in automatic control of TrA in people with LBP. Furthermore, the data establish a new test of recruitment of the abdominal muscles in people with LBP. This test presents a feasible noninvasive test of automatic recruitment of the abdominal muscles.

Comment: Manual muscle testing is an obvious, feasible, and noninvasive test for the adequate recruitment of the abdominal muscles in patients with low back pain. The inhibition of the abdominal muscles in patients with low back pain is a consistent finding in AK therapeutics.

Delayed onset of transversus abdominus in long-standing groin pain, Cowan SM, Schache AG, Brukner P, Bennell KL, Hodges PW, Coburn P, Crossley KM.

Med Sci Sports Exerc. 2004 Dec;36(12):2040-5.

Abstract: Long-standing groin pain is a persistent problem that is commonly difficult to rehabilitate. Theoretical rationale indicates a relationship between the motor control of the pelvis and long-standing groin pain; however, this link has not been investigated. PURPOSE: The current experiment aimed to evaluate motor control of the abdominal muscles in a group of Australian football players with and without long-standing groin pain. METHODS: Ten participants with long-standing groin pain and 12 asymptomatic controls were recruited for the study. Participants were elite or subelite Australian football players. Fine-wire and surface electromyography electrodes were used to record the activity of the selected abdominal and leg muscles during a visual choice reaction-time task (active straight leg raising). RESULTS: When the asymptomatic controls completed the active straight leg raise (ASLR) task, the transversus abdominus contracted in a feed-forward manner. However, when individuals with long-standing groin pain completed the ASLR task, the onset of transversus abdominus was delayed (P < 0.05) compared with the control group. There were no differences between groups for the onset of activity of internal oblique, external oblique, and rectus abdominus (all P > 0.05). CONCLUSIONS: The finding that the onset of transversus abdominus is delayed in individuals with long-standing groin pain is important, as it demonstrates an association between long-standing groin pain and transversus abdominus activation.

Changes in the cross-sectional area of multifidus and psoas in patients with unilateral back pain: the relationship to pain and disability, Barker KL, Shamley DR, Jackson D.

Spine. 2004 Nov 15;29(22):E515-9.

STUDY DESIGN: Prospective, cross-sectional observational study. OBJECTIVES: The aim of this study was to determine if there was an association between wasting of psoas and multifidus as observed on MRI scans and the presenting symptoms, reported pathology, pain, or disability of a cohort of patients presenting with unilateral low back pain. SUMMARY OF BACKGROUND DATA: Current physiotherapy practice is often based on localized spine stabilizing muscle exercises; most attention has been focused on transversus abdominus and multifidus with relatively little on psoas. METHOD: Fifty consecutive patients presenting to a back pain triage clinic with unilateral low back pain lasting more than 12 weeks were recruited. The cross-sectional surface area (CSA) of the muscles was measured. Duration of symptoms, rating of pain, self-reported function, and the presence of neural compression were recorded. RESULTS: Data analysis compared the CSA between the symptomatic and asymptomatic sides. There was a statistically significant difference in CSA between the sides (P < 0.001). There was a positive correlation between the percentage decrease in CSA of psoas on the affected side and with the rating of pain (rho = 0.608, P < 0.01), reported nerve root compression (rho = 0.812, P < 0.01), and the duration of symptoms (rho = 0.886, P < 0.01). There was an association between decrease in the CSA of multifidus and duration of symptoms. CONCLUSIONS: Atrophy of multifidus has been used as one of the rationales for spine stabilization exercises. The evidence of coexisting atrophy of psoas and multifidus suggests that a future area for study should be selective exercise training of psoas, which is less commonly used in clinical practice.

Comment: Psoas muscle dysfunction has been suggested as a major contributor to many cases of low back pain. Successful treatment of the psoas muscle dysfunction is critical to the resolution of low back pain in these cases.

The efficiency of spinal manipulation in otorhinolaryngology. A retrospective long-term study, Hulse M, Holzl M.

HNO. 2004 Mar;52(3):227-34.

BACKGROUND: The vertebral genesis of many functional disorders in otorhinolaryngology, such as dizziness, hearing-impairment, ear-pressure, ear-pain, foreign body sensation in the throat and dysphonia, is suggested by the success of spinal manipulative therapy, particularly of the atlanto-occipital joint. Up to now, there are no retrospective investigations which show the duration of the therapeutic effect. METHODS: We examined 220 patients with cervical otorhinolaryngological disorders (100 patients with dizziness, 49 with hearing impairment, 47 with tinnitus and 24 with dysphonia) after cervical manipulation lasting more than 6 months. RESULTS AND CONCLUSIONS: The extraordinary satisfaction with the manipulative therapy in 82% of patients with dizziness (46% total relief, 36% high improvement) reflects the high efficiency of this manual therapy. In contrast to these results, only 10% of patients with tinnitus showed an improvement (P<0.001). This retrospective investigation demonstrates that a successful outcome after manual therapy is not based on a "placebo effect".

An exploratory study of provocation testing with padded wedges: can prone blocking demonstrate a directional preference? Lisi AJ, Cooperstein R, Morschhauser E.

J Manipulative Physiol Ther. 2004 Feb;27(2):103-8

BACKGROUND: Currently, no traditional chiropractic examination method to determine a spinal listing offers demonstrated guidance in treatment decisions for low back pain (LBP) patients. Development of an examination that bypasses the difficulty of accurately and reliably identifying a listing, yet provides guidance on manipulative vectors, could be very valuable to clinicians and patients. OBJECTIVE: To explore 2 potential protocols for provocation testing and assessment of directional preference using padded wedges. METHODS: Two groups of 20 subjects were examined while lying prone on various positions of padded wedges. In the first group, pain pressure threshold (PPT) was measured at 4 anatomic points; in the second group, tenderness was measured at 1 anatomic point. We investigated whether either method could demonstrate a directional preference response. RESULTS: When tenderness was measured at 1 anatomic point, 70% of subjects demonstrated a directional response, and only 1 subject exhibited an increase in baseline tenderness at the end of the procedure. When PPT was measured at 4 anatomic points, 40% of subjects demonstrated a directional response, but 12 subjects exhibited decreased PPT at the end of the procedure. CONCLUSION: Measuring changes in tenderness at 1 anatomic point in response to various padded wedge patterns appears promising as an examination procedure to determine directional preference.

Comment: The category system of analysis was developed by DeJarnette and expanded by Goodheart. This system organizes patterns of various possible bodily distortions, particularly the disturbances that occur in the sacroiliac and lumbosacral regions.  Briefly, Category I relates to imbalance or torque at the anterior aspect of the sacroiliac junction and its affect on meningeal balance and CSF fluctuation.  Category II is associated with various degrees of posterior sacroiliac joint ligamentous sprain and trauma.  A Category III condition will occur when the pelvis can no longer maintain weight-bearing capacity and shifts the "burden" to the lumbosacral junction with resultant discopathy and radiculopathy. These pelvic distortions produce reciprocal distortions throughout the body, especially in the pectoral girdle and first rib heads, the TMJ, the cervical spine, and the skull. Many muscle groups will be involved in the compensations a body makes to these pelvic category distortions.

A comparison of muscle strength testing techniques in amyotrophic lateral sclerosis,

Great Lakes ALS Study Group.

Neurology. 2003 Dec 9;61(11):1503-7.

OBJECTIVE: To assess the reliability of strength testing techniques among centers investigating patients with amyotrophic lateral sclerosis. METHODS: The authors compared test reliability in manual muscle testing (MMT) and maximal voluntary isometric contraction (MVIC) scores among institutions and test validity by comparing change over time between MMT and MVIC. The authors examined 63 subjects at 3-month intervals for 12 months. At enrollment and at 6 months, two physical therapists each examined the subjects twice. MMT scores were calculated as modifications of the Medical Research Council scale. MVIC scores were generated as standardized megascores. Intraclass correlation coefficients and coefficients of variation compared reproducibility, and Pearson correlation coefficients compared change over time. The power of each measure to detect disease progression over time was assessed by estimating coefficients of variation for the average change. RESULTS: Reproducibility between MVIC and MMT was equivalent. Sensitivity to detect progressive weakness and power to detect this change, however, favored MMT, an effect largely accounted for by the number of muscles sampled. CONCLUSIONS: In multicentered trials, uniformly trained physical therapists reproducibly and accurately measure strength by both MMT and MVIC. The authors found MMT to be the preferred measure of global strength because of its better Pearson correlation coefficients, essentially equivalent reproducibility, and more favorable coefficient of variation.

Comment: This paper is very important in understanding the clinical value (validity) of MMT in patients with neurologic disorders. It demonstrates that MMT is a more sensitive, more reliable and valid measure of dysfunction in patients with ALS than MVIC, which is another common method of muscle function evaluation.

Development of motor system dysfunction following whiplash injury, Sterling M, Jull G, Vicenzino B, Kenardy J, Darnell R.

Pain. 2003 May;103(1-2):65-73.

Abstract: Dysfunction in the motor system is a feature of persistent whiplash associated disorders. Little is known about motor dysfunction in the early stages following injury and of its progress in those persons who recover and those who develop persistent symptoms. This study measured prospectively, motor system function (cervical range of movement (ROM), joint position error (JPE) and activity of the superficial neck flexors (EMG) during a test of cranio-cervical flexion) as well as a measure of fear of re-injury (TAMPA) in 66 whiplash subjects within 1 month of injury and then 2 and 3 months post injury. Subjects were classified at 3 months post injury using scores on the neck disability index: recovered (<8), mild pain and disability (10-28) or moderate/severe pain and disability (>30). Motor system function was also measured in 20 control subjects. All whiplash groups demonstrated decreased ROM and increased EMG (compared to controls) at 1 month post injury. This deficit persisted in the group with moderate/severe symptoms but returned to within normal limits in those who had recovered or reported persistent mild pain at 3 months. Increased EMG persisted for 3 months in all whiplash groups. Only the moderate/severe group showed greater JPE, within 1 month of injury, which remained unchanged at 3 months. TAMPA scores of the moderate/severe group were higher than those of the other two groups. The differences in TAMPA did not impact on ROM, EMG or JPE. This study identifies, for the first time, deficits in the motor system, as early as 1 month post whiplash injury, that persisted not only in those reporting moderate/severe symptoms at 3 months but also in subjects who recovered and those with persistent mild symptoms.

Comment: Patients who have experienced cervical trauma from whiplash dynamics often have perplexing symptoms. The standard orthopedic and neurologic examination often does not find a cause for the bizarre symptoms about which some patients complain. Manual muscle testing is a method for evaluating the function of the nervous system; it often reveals the cause, giving an understanding of the patient's many complaints.Failure to recognize problems in the motor system in whiplash patients, and failure to correct it is often the reason a patient is labeled as being a malingerer or having a psychoneurotic overlay to his condition, and is one of the reasons why symptoms from whiplash injuries can persist for many years.

Neck muscle fatigue affects postural control in man, Schieppati M, Nardone A, and Schmid M.

Neuroscience, 2003;121(2):277-285.

Abstract: We hypothesized that, since anomalous neck proprioceptive input can produce perturbing effects on posture, neck muscle fatigue could alter body balance control through a mechanism connected to fatigue-induced afferent inflow. Eighteen normal subjects underwent fatiguing contractions of head extensor muscles. Sway during quiet stance was recorded by a dynamometric platform, both prior to and after fatigue and recovery, with eyes open and eyes closed. After each trial, subjects were asked to rate their postural control. Fatigue was induced by having subjects stand upright and exert a force corresponding to about 35% of maximal voluntary effort against a device exerting a head-flexor torque. The first fatiguing period lasted 5 min (F1). After a 5-min recovery period (R1), a second period of fatiguing contraction (F2) and a second period of recovery (R2) followed. Surface EMG activity from dorsal neck muscles was recorded during the contractions and quiet stance trials. EMG median frequency progressively decreased and EMG amplitude progressively increased during fatiguing contractions, demonstrating that muscle fatigue occurred. After F1, subjects swayed to a larger extent compared with control conditions, recovering after R1. Similar findings were obtained after F2 and after R2. Although such behavior was detectable under both visual conditions, the effects of fatigue reached significance only without vision. Subjective scores of postural control diminished when sway increased, but diminished more, for equal body sway, after fatigue and recovery. Contractions of the same duration, but not inducing EMG signs of fatigue, had much less influence on body sway or subjective scoring. We argue that neck muscle fatigue affects mechanisms of postural control by producing abnormal sensory input to the CNS and a lasting sense of instability. Vision is able to overcome the disturbing effects connected with neck muscle fatigue.

Myoelectric manifestations of sternocleidomastoid and anterior scalene muscle fatigue in chronic neck pain patients, Falla D, Rainoldi A, Merletti R, Jull G.

Clin Neurophysiol. 2003 Mar;114(3):488-95.

OBJECTIVE: This study compares myoelectric manifestations of fatigue of the sternocleidomastoid (SCM) and anterior scalene (AS) muscles between 10 chronic neck pain subjects and 10 normal matched controls. METHODS: Surface electromyography (sEMG) signals were recorded from the sternal head of SCM and AS muscles bilaterally during sub-maximal isometric cervical flexion contractions at 25 and 50% of the maximum voluntary contraction (MVC). The mean frequency, average rectified value and conduction velocity of the sEMG signal were calculated to quantify myoelectric manifestations of muscle fatigue. RESULTS: For both the SCM and AS muscles, the Mann-Whitney U test indicated that the initial value and slope of the mean frequency in neck pain patients were greater than in healthy subjects (P < 0.05). This was significant both at 25 and 50% of MVC. CONCLUSIONS: These results suggest: (a) a predominance of type-II fibres in the neck pain patients and/or (b) greater fatigability of the superficial cervical flexors in neck pain patients. These results are in agreement with previous muscle biopsy studies in subjects with neck pain, which identified transformation of slow-twitch type-1 fibres to fast-twitch type-IIB fibres, as well as the clinical observation of reduced endurance in the cervical flexors in neck pain patients.

Association of widespread body pain with an increased risk of cancer and reduced cancer survival: a prospective, population-based study, McBeth J, Silman AJ, Macfarlane GJ

Arthritis Rheum. 2003 Jun;48(6):1686-92.

OBJECTIVE: To determine whether reported widespread body pain is related to an increased incidence of cancer and/or reduced survival from cancer, since our previous population surveys have demonstrated a relationship between widespread body pain and a subsequent 2-fold increase in mortality from cancer over an 8-year period. METHODS: A total of 6565 subjects in Northwest England participated in 2 health surveys during 1991-1992. The subjects were classified according to their reported pain status (no pain, regional pain, and widespread pain), and were subsequently followed up prospectively until December 31, 1999. During follow up, information was collected on incidence of cancer and survival rates among those developing cancer. Associations between the original pain status and development of cancer and cancer survival were expressed as the incidence rate ratio (IRR) and mortality rate ratio (MRR), respectively. All analyses were adjusted for age, sex, and study location, the latter being a proxy measure of socioeconomic status. RESULTS: Among the study population, 6331 had never been diagnosed with cancer at the time of participation in the survey. Of these subjects, 956 (15%) were classified as having widespread pain, 3061 (48%) as having regional pain, and 2314 (37%) as having no pain. There were a total of 395 first malignancies recorded during follow up. In comparison with subjects reporting no pain, those with regional pain (IRR 1.19, 95% confidence interval [95% CI] 0.94-1.50) and widespread pain (IRR 1.61, 95% CI 1.21-2.13) experienced an excess incidence of cancer during the follow up period. The increased incidence among subjects previously reporting widespread pain was related, most strongly, to breast cancer (IRR 3.67, 95% CI 1.39-9.68), but there were also cancers of the prostate (IRR 3.46, 95% CI 1.25-9.59), large bowel (IRR 2.35, 95% CI 0.96-5.77), and lung (IRR 2.04, 95% CI 0.96-4.34). Subjects reporting widespread pain who subsequently developed cancer, in comparison with those previously reporting no pain, had an increased risk of death (MRR 1.82, 95% CI 1.18-2.80). This decreased survival was highest among subjects with cancers of the breast and prostate, although the effects on site-specific survival were nonsignificant. CONCLUSION: This study has demonstrated that widespread pain reported in population surveys is associated with a substantial subsequent increased incidence of cancer and reduced cancer survival. At present there are no satisfactory biologic explanations for this observation, although several possible leads have been identified.

Comment: The importance of this study is that patients with spinal injuries that lead to aberrant afferent mechanical input into the spinal cord, ultimately resulting in chronic back pain, may face a statistically significant increase in death rates from cancer.

The use of osteopathic manipulative treatment as adjuvant therapy in children with recurrent acute otitis media, Mills MV, Henley CE, Barnes LL, Carreiro JE, Degenhardt BF.

Arch Pediatr Adolesc Med. 2003 Sep;157(9):861-6.

OBJECTIVE: To study effects of osteopathic manipulative treatment as an adjuvant therapy to routine pediatric care in children with recurrent acute otitis media (AOM). STUDY DESIGN: Patients 6 months to 6 years old with 3 episodes of AOM in the previous 6 months, or 4 in the previous year, who were not already surgical candidates were placed randomly into 2 groups: one receiving routine pediatric care, the other receiving routine care plus osteopathic manipulative treatment. Both groups received an equal number of study encounters to monitor behavior and obtain tympanograms. Clinical status was monitored with review of pediatric records. The pediatrician was blinded to patient group and study outcomes, and the osteopathic physician was blinded to patient clinical course. MAIN OUTCOME MEASURES: We monitored frequency of episodes of AOM, antibiotic use, surgical interventions, various behaviors, and tympanometric and audiometric performance. RESULTS: A total of 57 patients, 25 intervention patients and 32 control patients, met criteria and completed the study. Adjusting for the baseline frequency before study entry, intervention patients had fewer episodes of AOM (mean group difference per month, -0.14 [95% confidence interval, -0.27 to 0.00]; P =.04), fewer surgical procedures (intervention patients, 1; control patients, 8; P =.03), and more mean surgery-free months (intervention patients, 6.00; control patients, 5.25; P =.01). Baseline and final tympanograms obtained by the audiologist showed an increased frequency of more normal tympanogram types in the intervention group, with an adjusted mean group difference of 0.55 (95% confidence interval, 0.08 to 1.02; P =.02). No adverse reactions were reported. CONCLUSIONS: The results of this study suggest a potential benefit of osteopathic manipulative treatment as adjuvant therapy in children with recurrent AOM; it may prevent or decrease surgical intervention or antibiotic overuse.

Presence of Chapman reflex points in hospitalized patients with pneumonia,
Washington K, Mosiello R, Venditto M, Simelaro J, Coughlin P, Crow WT, Nicholas A.

J Am Osteopath Assoc. 2003 Oct;103(10):479-83.

Abstract: The authors undertook a case control study to determine whether hospitalized patients with pneumonia had reflex points in the anterior chest wall as described by Frank Chapman, DO, specifically those classified as relating to the lung. Sixty-nine hospitalized patients were enrolled in the study. Patients with an admitting diagnosis of pneumonia were compared to those without pneumonia as their admitting diagnosis. All patients were examined to determine if Chapman reflex points for the lungs were present. The study controlled for potential confounding diagnoses by excluding patients with lung pathology other than pneumonia. Results demonstrated a statistically significant relationship between the presence of Chapman reflex points and pneumonia in hospitalized patients.

Reliability of 4 outcome measures in pediatric spinal muscular atrophy, Iannaccone ST, Hynan LS, American Spinal Muscular Atrophy Randomized Trials (AmSMART) Group.

Arch Neurol. 2003 Aug;60(8):1130-6.

BACKGROUND: Spinal muscular atrophy is a common neurologic disorder of infants and children with a high mortality rate. Clinical trials have not been attempted in this population until recently. OBJECTIVE: To demonstrate that 4 outcome measures are reliable for use in clinical trials in patients with spinal muscular atrophy. DESIGN, SETTING, PATIENTS: Thirty-eight children with spinal muscular atrophy who fulfilled inclusion and exclusion criteria were enrolled at 5 pediatric centers for a reliability study. Paired samples statistics were performed comparing results of the qualifying variance visit with a fourth visit. MAIN OUTCOME MEASURES: Quantitative muscle testing and the Gross Motor Function Measure. RESULTS: Thirty-four patients and 7 evaluators completed the study. Thirteen patients were aged 2 through 4 years and 21 were 5 through 17 years. The Gross Motor Function Measure was completed by 34 subjects. Six variables for pulmonary function tests were measured in 20 subjects. Quantitative muscle testing was performed on 21 subjects in 8 muscle groups. Thirty-three subjects completed the PedsQL Neuromuscular Module for Parents. The intraclass correlation coefficient and Bradley-Blackwood procedures indicated a very high level of agreement between measures. CONCLUSION: The Gross Motor Function Measure, pulmonary function tests, quantitative muscle testing, and quality of life are reliable outcome measures for clinical trials in pediatric spinal muscular atrophy.

Pain and motor control of the lumbopelvic region: effect and possible mechanisms, Hodges PW, Moseley GL.

J Electromyogr Kinesiol. 2003 Aug;13(4):361-70.

Abstract: Many authors report changes in the control of the trunk muscles in people with low back pain (LBP). Although there is considerable disagreement regarding the nature of these changes, we have consistently found differential effects on the deep intrinsic and superficial muscles of the lumbopelvic region. Two issues require consideration; first, the potential mechanisms for these changes in control, and secondly, the effect or outcome of changes in control for lumbopelvic function. Recent data indicate that experimentally induced pain may replicate some of the changes identified in people with LBP. While this does not exclude the possibility that changes in control of the trunk muscles may lead to pain, it does argue that, at least in some cases, pain may cause the changes in control. There are many possible mechanisms, including changes in excitability in the motor pathway, changes in the sensory system, and factors associated with the attention demanding, stressful and fearful aspects of pain. A new hypothesis is presented regarding the outcome from differential effects of pain on the elements of the motor system. Taken together these data argue for strategies of prevention and rehabilitation of LBP.

Comment: In the AK clinical setting, MMT that produces pain during the test will also demonstrate inhibition of the muscle tested. When the proper therapy is employed, the MMT inhibition of the muscle and the pain during the MMT of the muscle are improved. This correlation is explored in this paper.

Evidence of altered lumbopelvic muscle recruitment in the presence of sacroiliac joint pain, Hungerford B, Gilleard W, Hodges P.

Spine. 2003 Jul 15;28(14):1593-600.

STUDY DESIGN: Cross-sectional study of electromyographic onsets of trunk and hip muscles in subjects with a clinical diagnosis of sacroiliac joint pain and matched control subjects. OBJECTIVES: To determine whether muscle activation of the supporting leg was different between control subjects and subjects with sacroiliac joint pain during hip flexion in standing. BACKGROUND: Activation of the trunk and gluteal muscles stabilize the pelvis for load transference; however, the temporal pattern of muscle activation and the effect of pelvic pain on temporal parameters has not been investigated. METHODS: Fourteen men with a clinical diagnosis of sacroiliac joint pain and healthy age-matched control subjects were studied. Surface electromyographic activity was recorded from seven trunk and hip muscles of the supporting leg during hip flexion in standing. Onset of muscle activity relative to initiation of the task was compared between groups and between limbs. RESULTS: The onset of obliquus internus abdominis (OI) and multifidus occurred before initiation of weight transfer in the control subjects. The onset of obliquus internus abdominis, multifidus, and gluteus maximus was delayed on the symptomatic side in subjects with sacroiliac joint pain compared with control subjects, and the onset of biceps femoris electromyographic activity was earlier. In addition, electromyographic onsets were different between the symptomatic and asymptomatic sides in subjects with sacroiliac joint pain. CONCLUSIONS: The delayed onset of obliquus internus abdominis, multifidus, and gluteus maximus electromyographic activity of the supporting leg during hip flexion, in subjects with sacroiliac joint pain, suggests an alteration in the strategy for lumbopelvic stabilization that may disrupt load transference through the pelvis.

Comment: The importance of specific treatment of muscle imbalances related to the sacroiliac joints is apparent from this study.

Comorbidity of internal derangement of the temporomandibular joint and silent dysfunction of the cervical spine, Stiesch-Scholz M, Fink M, Tschernitschek H.

J Oral Rehabil. 2003 Apr;30(4):386-91.

Abstract: The aim of this evaluation was to examine correlations between internal derangement of the temporomandibular joint (TMJ) and cervical spine disorder (CSD). A prospective controlled clinical study was carried out. Thirty patients with signs and symptoms of internal derangement but without any subjective neck problems and 30 age- and gender-matched control subjects without signs and symptoms of internal derangement were examined. The investigation of the temporomandibular system was carried out using a 'Craniomandibular Index'. Afterwards an examiner-blinded manual medical investigation of the craniocervical system was performed. This included muscle palpation of the cervical spine and shoulder girdle as well as passive movement tests of the cervical spine, to detect restrictions in the range of movement as well as segmental intervertebral dysfunction. The internal derangement of the TMJ was significantly associated with 'silent' CSD (t-test, P < 0.05). Patients with raised muscle tenderness of the temporomandibular system exhibited significantly more often pain on pressure of the neck muscles than patients without muscle tenderness of the temporomandibular system (t-test, P < 0.05). As a result of the present study, for patients with internal derangement of the TMJ an additional examination of the craniocervical system should be recommended.

Comment: In AK there is recognition of the stomatognathic system, and of the importance of the cervical spine to the treatment of the TMJ. The stomatognathic system involves the complex interaction between structures and functions of the head and neck.

The functional relationship between the craniomandibular system, cervical spine, and the sacroiliac joint: a preliminary investigation, Fink M, Wahling K, Stiesch-Scholz M, Tschernitschek H.

Cranio. 2003 Jul;21(3):202-8.

Abstract: The hypothesis of a functional coupling between the muscles of the craniomandibular system and the muscles of other body areas is still controversial. The purpose of this pilot study was to examine whether there is a relationship between the craniomandibular system, the craniocervical system and the sacropelvic region. To test this hypothesis, the prevalence and localization of dysfunction of the cervical spine and the sacroiliac joint were examined in a prospective, experimental trial. Twenty healthy students underwent an artificial occlusal interference, which caused an occlusal interference. The upper cervical spine (CO-C3) and the sacroiliac joint were examined before, during and after this experimental test. The primary outcome with these experimental conditions was the occurrence of hypomobile functional abnormalities. In the presence of occlusal interference, functional abnormalities were detected in both regions examined and these changes were statistically significant. The clinical implications of these findings may be that a complementary examination of these areas in CMD patients could be useful.

The"iliacus test": new information for theevaluation of hip extension dysfunction, Eland DC, Singleton TN, Conaster RR, Howell JN, Pheley AM, Karlene MM, Robinson JM.

JAOA. March 2002;102(3):130-142.

Abstract: This study confirms the clinical value of investigating the "iliacus complex" during evaluations of the low back. A new "iliacus test" isolates this iliacus complex component of limited hip extension. Designed for a single joint, the test isolates motion across the hip joint. Study results include the following: (1) in a comparison with the clinical standard, the Thomas test, data show that the two tests are significantly different in an asymptomatic population between the ages of 18 and 35 years; (2) with the exception of the standard Thomas test, the data show no statistical differences in range of motion when comparing the left side with the right side; (3) examiner-added, end-range pressure for assessment of range of motion when compared with the standard gravity-dependent end range of motion used in the Thomas test yields valuable new information; and (4) data provide a basis for population norms for each test--Thomas and iliacus--in gravity-dependent and examiner-produced tissue-feel end ranges.

Cervical muscle dysfunction in chronic whiplash-associated disorder grade 2: the relevance of the trauma, Nederhand MJ, Hermens HJ, IJzerman MJ, Turk DC, Zilvold G.

Spine. 2002 May 15;27(10):1056-61.

STUDY DESIGN: Surface electromyography measurements of the upper trapezius muscles were performed in patients with a chronic whiplash-associated disorder Grade 2 and those with nonspecific neck pain. OBJECTIVE: To determine the etiologic relation between acceleration-deceleration trauma and the presence of cervical muscle dysfunction in the chronic stage of whiplash-associated disorder. SUMMARY OF BACKGROUND INFORMATION: From a biopsychosocial perspective, the acceleration-deceleration trauma in patients with whiplash-associated disorder is not regarded as a cause of chronicity of neck pain, but rather as a risk factor triggering response systems that contribute to the maintenance of neck pain. One of the contributing factors is dysfunction of the cervical muscles. Considering the limited etiologic significance of the trauma, it is hypothesized that in patients with neck pain, there are no differences in muscle activation patterns between those with and those without a history of an acceleration-deceleration trauma. METHODS: Muscle activation patterns, expressed in normalized smooth rectified electromyography levels of the upper trapezius muscles, in patients with whiplash-associated disorder Grade 2 were compared with those of patients with nonspecific neck pain. The outcome parameters were the mean level of muscle activity before and after a physical exercise, the muscle reactivity in response to the exercise, and the time-dependent behavior of muscle activity after the exercise. RESULTS: There were no statistical significant differences in any of the outcome parameters between patients with whiplash-associated disorder Grade 2 and those with nonspecific neck pain. There was only a tendency of higher muscle reactivity in patients with whiplash-associated disorder Grade 2. CONCLUSIONS: It appears that the cervical muscle dysfunction in patients with chronic whiplash-associated disorder Grade 2 is not related to the specific trauma mechanism. Rather, cervical muscle dysfunction appears to be a general sign in diverse chronic neck pain syndromes.

Comment: This is another paper by Nederhand et al that is very important for AK. In terms of the etiology of symptoms from chronic whiplash disorders, this study suggests that the performance of the upper trapezius muscle is an invaluable diagnostic measurement in the evaluation of patients with chronic neck pain and chronic whiplash-associated disorders. The evaluation and treatment of upper trapezius muscle dysfunction is a standard part of AK therapy.

Do cerebral potentials to magnetic stimulation of paraspinal muscles reflect changes in palpable muscle spasm, low back pain, and activity scores? Zhu Y, Haldeman S, Hsieh CY, Wu P, Starr A.

J Manipulative Physiol Ther. 2002 Jan;25(1):77-8.

OBJECTIVE: Previous studies have shown that cortical-evoked potentials on magnetic stimulation of muscles are influenced by muscle contraction, vibration, and muscle spasm. This study was carried out to determine whether these potentials correlate with palpatory muscle spasm, patient symptoms, and disability in patients with low back pain. METHODS: A prospective observational study was performed on 13 subjects with a history of low back pain visiting an orthopedic hospital-based clinic. Patients were screened for serious pathologic conditions by an orthopedic surgeon. The patients were then evaluated for the presence of muscle spasm by one of the investigators who was blinded to the results of the evoked potential studies. Patients were asked to complete a low back pain visual analogue scale (VAS) and a Roland-Morris Activity Scale (RMAS). Cortical-evoked potentials were recorded with a magnetic stimulator placed over the lumbar paraspinal muscles with the patient in the prone position. The palpatory examination, VAS, RMAS, and the cortical potentials were repeated after 2 weeks of therapy commonly used to reduce muscle spasm. RESULTS: The patients demonstrated a significant decrease in low back pain VAS and RMAS scores after treatment compared with before treatment. There was a reduction in the amount of palpatory muscle spasm in 11 of 13 cases. The cortical potentials before treatment were attenuated compared with previously reported controls and showed a significant increase before and after treatment in the amplitude of these potentials with multivariate analysis of variance. There was significant correlation between the changes in cortical potentials after treatment and the changes noted in paraspinal muscle spasm and VAS and RMAS scores. CONCLUSIONS: This study confirms the previous report that the amplitude of cerebral-evoked potentials on magnetic stimulation of paraspinal muscles is depressed in the presence of palpable muscle spasm. The close correlation among these potentials, paraspinal muscle spasm, and clinical symptoms suggests that the measurement of muscle activity may be more important in the assessment of low back pain than is commonly accepted.

Comment: This hypothesis has been made in AK since the technique was founded. Through evaluation of the function of certain muscles pre- and post-treatment, therapeutic efficacy for particular problems can be evaluated. Applied kinesiologists theorize that physical, chemical, and mental imbalances are associated with secondary muscle dysfunction – specifically a muscle inhibition (usually preceding an overfacilitation of an opposing muscle). Applying the proper therapy results in improvement in the inhibited muscle. This study demonstrates the simultaneous presence of muscle spasm and depressed cortical-evoked potentials in patients with low back pain. After 2 weeks of chiropractic spinal therapy the patients were alleviated of their clinical symptoms and increased the synaptic efficacy of Ia afferent activation to the central nervous system.

Exercise-induced muscle damage in humans, Clarkson PM, Hubal MJ.

Am J Phys Med Rehabil. 2002 Nov;81(11 Suppl):S52-69.

Abstract: Exercise-induced muscle injury in humans frequently occurs after unaccustomed exercise, particularly if the exercise involves a large amount of eccentric (muscle lengthening) contractions. Direct measures of exercise-induced muscle damage include cellular and subcellular disturbances, particularly Z-line streaming. Several indirectly assessed markers of muscle damage after exercise include increases in T2 signal intensity via magnetic resonance imaging techniques, prolonged decreases in force production measured during both voluntary and electrically stimulated contractions (particularly at low stimulation frequencies), increases in inflammatory markers both within the injured muscle and in the blood, increased appearance of muscle proteins in the blood, and muscular soreness. Although the exact mechanisms to explain these changes have not been delineated, the initial injury is ascribed to mechanical disruption of the fiber, and subsequent damage is linked to inflammatory processes and to changes in excitation-contraction coupling within the muscle. Performance of one bout of eccentric exercise induces an adaptation such that the muscle is less vulnerable to a subsequent bout of eccentric exercise. Although several theories have been proposed to explain this "repeated bout effect," including altered motor unit recruitment, an increase in sarcomeres in series, a blunted inflammatory response, and a reduction in stress-susceptible fibers, there is no general agreement as to its cause. In addition, there is controversy concerning the presence of sex differences in the response of muscle to damage-inducing exercise. In contrast to the animal literature, which clearly shows that females experience less damage than males, research using human studies suggests that there is either no difference between men and women or that women are more prone to exercise-induced muscle damage than are men.

Comment: The first technique used in AK to change muscle function was firm manipulation of the muscle’s origin and insertion. When muscle weakness was found on MMT, small nodules at the origin or insertion were often present in the muscle. A history of trauma to the muscle will usually be present. Significant research on muscle soreness has focused on eccentric muscle contractions. During this type of muscular movement, muscles lengthen, which causes the microtears characteristic of exercise-induced muscle damage. The AK hypothesis that in some cases muscle weakness is due to a microavulsion of the tendon from the periosteum finds substantiation in this study.

Neurophysiological effects of spinal manipulation, Pickar JG.

Spine J. 2002 Sep-Oct;2(5):357-71.

BACKGROUND CONTEXT: Despite clinical evidence for the benefits of spinal manipulation and the apparent wide usage of it, the biological mechanisms underlying the effects of spinal manipulation are not known. Although this does not negate the clinical effects of spinal manipulation, it hinders acceptance by the wider scientific and health-care communities and hinders rational strategies for improving the delivery of spinal manipulation. PURPOSE: The purpose of this review article is to examine the neurophysiological basis for the effects of spinal manipulation. STUDY DESIGN: A review article discussing primarily basic science literature and clinically oriented basic science studies. METHODS: This review article draws primarily from the peer-reviewed literature available on Medline. Several textbook publications and reports are referenced. A theoretical model is presented describing the relationships between spinal manipulation, segmental biomechanics, the nervous system and end-organ physiology. Experimental data for these relationships are presented. RESULTS: Biomechanical changes caused by spinal manipulation are thought to have physiological consequences by means of their effects on the inflow of sensory information to the central nervous system. Muscle spindle afferents and Golgi tendon organ afferents are stimulated by spinal manipulation. Smaller-diameter sensory nerve fibers are likely activated, although this has not been demonstrated directly. Mechanical and chemical changes in the intervertebral foramen caused by a herniated intervertebral disc can affect the dorsal roots and dorsal root ganglia, but it is not known if spinal manipulation directly affects these changes. Individuals with herniated lumbar discs have shown clinical improvement in response to spinal manipulation. The phenomenon of central facilitation is known to increase the receptive field of central neurons, enabling either subthreshold or innocuous stimuli access to central pain pathways. Numerous studies show that spinal manipulation increases pain tolerance or its threshold. One mechanism underlying the effects of spinal manipulation may, therefore, be the manipulation's ability to alter central sensory processing by removing subthreshold mechanical or chemical stimuli from paraspinal tissues. Spinal manipulation is also thought to affect reflex neural outputs to both muscle and visceral organs. Substantial evidence demonstrates that spinal manipulation evokes paraspinal muscle reflexes and alters motoneuron excitability. The effects of spinal manipulation on these somatosomatic reflexes may be quite complex, producing excitatory and inhibitory effects. Whereas substantial information also shows that sensory input, especially noxious input, from paraspinal tissues can reflexively elicit sympathetic nerve activity, knowledge about spinal manipulation's effects on these reflexes and on end-organ function is more limited. CONCLUSIONS: A theoretical framework exists from which hypotheses about the neurophysiological effects of spinal manipulation can be developed. An experimental body of evidence exists indicating that spinal manipulation impacts primary afferent neurons from paraspinal tissues, the motor control system and pain processing. Experimental work in this area is warranted and should be encouraged to help better understand mechanisms underlying the therapeutic scope of spinal manipulation.

Comment: This important review of the current scientific literature suggests that spinal manipulation alters group Ia and group II mechanoreceptor discharge and significantly affects the motor control system. Central motor facilitation is a basic, immediate neurophysiological response to chiropractic care. This paper reviews the evidence that reductions in resting muscular tone (quantified by surface electromyography in the prone posture) have been documented following spinal adjustments, as have improvements in muscular strength.

Central motor excitability changes after spinal manipulation: A transcranial magnetic stimulation study, Dishman J, Ball K, Burke J.

J Manipulative Physiol Ther 2002;25:1-9

Background: The physiologic mechanism by which spinal manipulation may reduce pain and muscular spasm is not fully understood. One such mechanistic theory proposed is that spinal manipulation may intervene in the cycle of pain and spasm by affecting the resting excitability of the motoneuron pool in the spinal cord. Previous data from our laboratory indicate that spinal manipulation leads to attenuation of the excitability of the motor neuron pool when assessed by means of peripheral nerve Ia-afferent stimulation (Hoffmann reflex). Objective: The purpose of this study was to determine the effects of lumbar spinal manipulation on the excitability of the motor neuron pool as assessed by means of transcranial magnetic stimulation. Methods: Motor-evoked potentials were recorded subsequent to transcranial magnetic stimulation. The motor-evoked potential peak-to-peak amplitudes in the right gastrocnemius muscle of healthy volunteers (n = 24) were measured before and after homolateral L5-S1 spinal manipulation (experimental group) or side-posture positioning with no manipulative thrust applied (control group). Immediately after the group-specific procedure, and again at 5 and 10 minutes after the procedure, 10 motor-evoked potential responses were measured at a rate of 0.05 Hz. An optical tracking system (OptoTRAK, Northern Digital Inc, Waterloo, Canada [<0.10 mm root-mean-square]) was used to monitor the 3-dimensional (3-D) position and orientation of the transcranial magnetic stimulation coil, in real time, for each trial. Results: The amplitudes of the motor-evoked potentials were significantly facilitated from 20 to 60 seconds relative to the pre baseline value after L5-S1 spinal manipulation, without a concomitant change after the positioning (control) procedure. Conclusions: When motor neuron pool excitability is measured directly by central corticospinal activation with transcranial magnetic stimulation techniques, a transient but significant facilitation occurs as a consequence of spinal manipulation. Thus, a basic neurophysiologic response to spinal manipulation is central motor facilitation.

Assessment of isokinetic muscle strength in women who are obese, Hulens M, Vansant G, Lysens R, Claessens AL, Muls E.

-- Department of Rehabilitation Sciences, Faculty of Physical Education and Physiotherapy, Katholieke Universiteit, Leuven, Belgium. maria.hulens@flok.kuleuven.ac.be

J Orthop Sports Phys Ther. 2002 Jul;32(7):347-56. 

STUDY DESIGN: Cross-sectional study of isokinetic trunk and knee muscle strength in women who are obese. OBJECTIVE: To provide reference values, to identify variables that affect peripheral muscle strength, and to provide recommendations for isokinetic testing of trunk and knee muscles in women who are obese and morbidly obese. BACKGROUND: The assessment of peripheral muscle strength is useful for the quantification of possible loss of strength, for exercise prescription, and for the evaluation of the effect of training programs in obese individuals. METHODS AND MEASURES: Isokinetic trunk and leg muscle strength was assessed in 241 women who were obese (18-65 years, body mass index (BMI) > or = 30 kg/m2). Trunk flexion and extension peak torque (PT) was measured using the Cybex TEF dynamometer; trunk rotation (TR) PT was measured using the Cybex TORSO dynamometer; and knee flexion/extension (KFE) PT was measured using the Cybex 350 dynamometer. Body composition was assessed using the bioelectrical impedance method; physical activity was assessed using the Baecke questionnaire; and peak VO2 was assessed using an incremental exercise capacity test on a bicycle ergometer. To identify variables related to muscle strength, Pearson correlations were computed and a stepwise multiple regression analysis was performed. RESULTS: Pearson correlation coefficients of all strength measurements at 60 degrees/s revealed low-to-moderate negative associations with age and positive associations with mass, height, fat free mass (FFM), and peak VO2 (P < 0.05), except for gravity-uncorrected trunk extension strength, which was not related to mass. The sports index of the Baecke questionnaire was associated with TR PT (r = 0.20, P < 0.01) and KFE PT (r = 0.18, P < 0.05). CONCLUSION: The weight of the trunk accounts largely for the measured trunk extensor and flexor strength in women who are obese. Contributing variables of isokinetic trunk flexion and extension strength in women who are obese are age, height, and FFM; whereas sports activities and aerobic fitness are contributing factors for trunk rotational and knee extension strength. Recommendations for measuring isokinetic muscle strength in individuals who are obese are provided.

Decrease in elbow flexor inhibition after cervical spine manipulation in patients with chronic neck pain, Suter E, McMorland G.

Clin Biomech (Bristol, Avon). 2002 Aug;17(7):541-4.

OBJECTIVE: This study measured functional capacity and subjective pain in patients with chronic neck pain before and after manipulation of the cervical spine. DESIGN: Outcomes study on 16 patients with chronic neck pain. BACKGROUND: Muscle inhibition, i.e., the inability to fully activate a muscle, has been observed following joint pathologies and in low back pain conditions. Although chronic neck pain has been associated with changes in muscle recruitment and coordination in the shoulder and arms, the possibility of muscle inhibition has not been explored. METHODS: Biceps activation during a maximal voluntary elbow flexor contraction was assessed using the interpolated twitch technique and electromyography. Cervical range of motion and pressure pain thresholds were measured using a goniometer and an algometer. Manipulation of the cervical spine was applied at the level of C5/6/7, and functional assessments were repeated. RESULTS: Patients showed significant inhibition in their biceps muscles. Cervical range of motion was restricted laterally, and increased pressure pain sensitivity was evident. After cervical spine manipulation, a significant reduction in biceps inhibition and an increase in biceps force occurred. Cervical range of motion and pressure pain thresholds increased significantly. CONCLUSIONS: Significant dysfunction in biceps activation was evident in patients with chronic neck pain, indicating that this muscle group cannot be used to the full extent. Spinal manipulation decreased muscle inhibition and increased elbow flexor strength at least in the short term. RELEVANCE: Muscle inhibition in the biceps has not been previously documented in patients with chronic neck pain. Further research is needed to establish whether muscle inhibition is related to clinical symptoms and functional outcome. Spinal manipulation improved muscle function, cervical range of motion and pain sensitivity, and might therefore be beneficial for treating patients with chronic neck pain.

Comment: The relationship between spinal dysfunction and muscular inhibition is very clearly demonstrated in this paper.

The reliability of upper- and lower-extremity strength testing in a community survey of older adults, Ottenbacher KJ, Branch LG, Ray L, Gonzales VA, Peek MK, Hinman MR.

-- Division of Rehabilitation Sciences, Sealy Center on Aging, University of Texas Medical Branch, Galveston, TX 77555-1028, USA. kottenbo@utmb.edu

Arch Phys Med Rehabil. 2002 Oct;83(10):1423-7.

OBJECTIVE: To examine the stability (test-retest reliability) of strength measures in older adults obtained by nontherapist lay examiners by using a hand-held portable muscle testing device (Nicholas Manual Muscle Tester). DESIGN: A prospective relational design was used to collect test-retest data for 1 male subject by using 27 lay raters who completed intensive training in manual muscle. SETTING: Data were collected from older Mexican-American adults living in the community. PARTICIPANTS: Twenty-seven lay raters who completed intensive training in manual muscle testing for a field-based assessment and interview of older adults and 63 Mexican-American subjects completing wave 4 of the Hispanic Established Populations for the Epidemiologic Study of the Elderly. INTERVENTIONS: Training involved reviewing a manual describing each testing position followed by approximately 6 hours of instruction and practice supervised by an experienced physical therapist. Lay raters then collected test-retest information on older Mexican-American subjects. MAIN OUTCOME MEASURE: Stability (test-retest) for a portable manual muscle testing device. RESULTS: Intraclass correlation coefficients (ICCs) were computed for the 27 lay raters examining 1 male subject (2 trials) and 12 lay raters assessing 63 older Mexican-American adults (1 practice and 2 trials recorded). The ICC values for the first 27 lay raters ranged from .74 to.96. The ICC values for the latter 12 lay raters ranged from .87 to.98. No differences were found in ICC values between male or female subjects. CONCLUSIONS: Stable and consistent information for upper- and lower-extremity strength was collected from the older adults participating in this study. The results suggest reliable information can be obtained by lay raters using a portable manual muscle testing device if the examiners receive intensive training.

Sensorimotor control of the spine, Holm, S., Indahl, A., Solomonow, M. 

Journal of Electromyography and Kinesiology, 2002,12;3:219-234.

(http://www.isek-online.org/)

Abstract: The spinal viscoelastic structures including disk, capsule and ligaments were reviewed with special focus on their sensory motor functions. Afferent capable of monitoring proprioceptive and kinesthetic information are abundant in the disc, capsule and ligament. Electrical stimulation of the lumbar afferents in the discs, capsules and ligaments seem to elicit reflex contraction of the multifidus and also longissimus muscles. The muscular excitation is pronounced in the level of excitation and with weaker radiation 1 to 2 levels above and below. Similarly, mechanical stimulation of the spinal viscoelastic tissues excites the muscles with higher excitation intensity when more than one tissue (ligaments and discs for example) is stimulated. Overall, it seems that spinal structures are well suited to monitor sensory information as well as to control spinal muscles and probably also provide kinesthetic perception to the sensory cortex.

Comment: The new and strikingly original feature of AK is that it brings together in a functional, inseparable manner the spinal, the nervous, and the muscle systems. Remarkably, each system demonstrates and maintains the condition of the other.

The effect of different standing and sitting postures on trunk muscle activity in a pain-free population, O'Sullivan PB, Grahamslaw KM, Kendell M, Lapenskie SC, Moller NE, Richards KV.

Spine. 2002 Jun 1;27(11):1238-44.

STUDY DESIGN: A normative, single-group study was conducted. OBJECTIVE: To determine whether there is a difference in electromyographic activation of specific lumbopelvic muscles with the adoption of common postures in a pain-free population. SUMMARY OF BACKGROUND DATA: Clinical observations indicate that adopting passive postures such as sway standing and slump sitting can exacerbate pain in individuals with low back pain. These individuals often present with poor activation of the lumbopelvic stabilizing musculature. At this writing, little empirical evidence exists to document that function of the trunk and lumbopelvic musculature are related to the adoption of standardized standing and sitting postures. METHODS: This study included 20 healthy adults, with equal representation of the genders. Surface electromyography was used to measure activity in the superficial lumbar multifidus, internal oblique, rectus abdominis, external oblique, and thoracic erector spinae muscles for four standardized standing and sitting postures. RESULTS: The internal oblique, superficial lumbar multifidus, and thoracic erector spinae muscles showed a significant decrease in activity during sway standing (P = 0.027, P = 0.002, and P = 0.003, respectively) and slump sitting (P = 0.007, P = 0.012, and P = 0.003, respectively), as compared with erect postures. Rectus abdominis activity increased significantly in sway standing, as compared with erect standing (P = 0.005). CONCLUSIONS: The findings show that the lumbopelvic stabilizing musculature is active in maintaining optimally aligned, erect postures, and that these muscles are less active during the adoption of passive postures. The results of this study lend credence to the practice of postural retraining when facilitation of the lumbopelvic stabilizing musculature is indicated in the management of specific spinal pain conditions.

Chiropractic 'name techniques': a review of the literature, Gleberzon BJ.

European Journal of Chiropractic 2002; 49: 242-3.

Abstract: The purpose of this paper is to describe the results of a literature search of several different chiropractic 'name techniques.' This process is an important first step in building an evidentiary foundation upon which clinical decisions should be made, and it further guides research efforts by exposing those areas which are insufficiently investigated. Out of the 111 articles found in this study, 39 were technique descriptions (35%), 29 were case studies or case series (26%), 25 were experimental studies (23%), and only 17 (15%) were clinical trials. Out of the clinical trial, only five were designed with a treatment group/control group and only one study was designed with a treatment group/sham treatment group. None of these clinical trials were designed with a treatment/sham/control group protocol. It is equally problematic that those studies which investigated the intra- and inter-reliability of such diagnostic tests as leg length checks or X-ray mensurations have not linked these tests with any clinical applicability or relevance. Thus it is fair to state that the current body of research into name techniques is still in its infancy. Therefore, it is incumbent upon advocates of name techniques to continue to establish an evidentiary base to support the utilization of their diagnostic or therapeutic procedures.

Comment: Research is one of ICAK’s priorities. The Collected Papers of the International College of Applied Kinesiology has been published both annually and bi-annually since the founding of the ICAK in 1976, and are available for review on this website. The sharing of the clinical observations and ideas in this yearly publication is the launching of a researching idea, and a step up a path where too few in the health care community have gone. As patient-based outcomes assessment are a growing part of evidence-based health care throughout the healing professions, more studies are needed that evaluate patient responses to therapy. There have been over 2,000 papers in 40 Annual Yearbooks published by members of the ICAK, taking the organization from its infancy toward its maturity.

Chiropractic Name Techniques in Canada: A Continued Look at Demographic Trends and Their Impact on Issues of Jurisprudence, Gleberzon BJ.

J Can Chiropr Assoc 2002; 46(4): 241-56.

Abstract: In a previous article, the author reported on the recommendations gathered from student projects between 1996-1999 investigating their preferences for including certain chiropractic Name technique systems into the curriculum at the Canadian Memorial Chiropractic College (CMCC). These results were found to be congruent with the professional treatment techniques used by Canadian chiropractors. This article reports on date obtained during the 2002 and 2001 academic years, comparing these results to those previously gathered. In addition, because of the implementation of a new curriculum during this time period, there was a unique opportunity to observe whether or not student perceptions differed between those students in the 'old' curricular program , and those students in the 'new' curricular program. The results gathered indicate that students in both curricular programs show an interest in learning Thompson Terminal Point, Activator Methods, Gonstead, and Active Release Therapy techniques in the core curriculum, as an elective, or during continuing educational programs provided by the college. Students continue to show less interest in learning CranioSacral Therapy, Sacro Occipital Technique, Logan Basic, Applied Kinesiology and Chiropractic BioPhysics. Over time, student interest has moved away from Palmer HIO and other upper cervical techniques, and students show a declining interest in being offered instruction in either Network Spinal Analysis or Torque Release Techniques. Since these findings reflect the practice activities of Canadian chiropractors they may have implications not only towards pedagogical decision-making process at CMCC, but may also influence professional standards of care.

Patients using chiropractors in North America: who are they, and why are they in chiropractic care? Coulter ID, Hurwitz EL, Adams AH, Genovese BJ, Hays R, Shekelle PG.

Spine. 2002 Feb 1;27(3):291-6; discussion 297-8.

SUMMARY OF BACKGROUND DATA AND OBJECTIVES: Alternative health care was used by an estimated 42% of the U.S. population in 1997, and chiropractors accounted for 31% of the total estimated number of visits. Despite this high level of use, there is little empirical information about who uses chiropractic care or why. METHODS: The authors surveyed randomly sampled chiropractors (n = 131) at six study sites and systematically sampled chiropractic patients seeking care from participating chiropractors on 1 day (n = 1275). Surveys collected data about the patient's reason for seeking chiropractic care, health status, health attitude and beliefs, and satisfaction. In addition to descriptive statistics, the authors compared data between patients and chiropractors, and between patients and previously published data on health status from other populations, corrected for the clustering of patients within chiropractors. RESULTS: More than 70% of patients specified back and neck problems as their health problem for which they sought chiropractic care. Chiropractic patients had significantly worse health status on all SF-36 scales than an age- and gender-matched general population sample. Compared with medical back pain patients, chiropractic back pain patients had significantly worse mental health (6-8 point decrement). Roland-Morris scores for chiropractic back pain patients were similar to values reported for medical back pain patients. The health attitudes and beliefs of chiropractors and their patients were similar. Patients were very satisfied with their care. CONCLUSION: These data support the theory that patients seek chiropractic care almost exclusively for musculoskeletal symptoms and that chiropractors and their patients share a similar belief system.

Electromyographic reflex response to mechanical force, manually-assisted spinal manipulative therapy, Colloca CJ, Keller TS.

Spine, 2001;26:1117-24

(http://www.journals.elsevierhealth.com/periodicals/ymmt/medline/record/MDLN.11413422)

Study Design: Surface electromyographic reflex responses associated with mechanical force, manually assisted (MFMA) spinal manipulative therapy were analyzed in this prospective clinical investigation of 20 consecutive patients with low back pain.

Objectives: To characterize and determine the magnitude of electromyographic reflex responses in human paraspinal muscles during high loading rate mechanical force, manually assisted spinal manipulative therapy of the thoracolumbar spine and sacroiliac joints.  Summary of Background Data: Spinal manipulative therapy has been investigated for its effectiveness in the treatment of patients with low back pain, but its physiologic mechanisms are not well understood. Noteworthy is the fact that spinal manipulative therapy has been demonstrated to produce consistent reflex responses in the back musculature; however, no study has examined the extent of reflex responses in patients with low back pain. Methods: Twenty patients (10 male and 10 female, mean age 43.0 years) underwent standard physical examination on presentation to an outpatient chiropractic clinic. After repeated isometric trunk extension strength tests, short duration (<5 msec), localized posteroanterior manipulative thrustswere delivered to the sacroiliac joints, and L5, L4, L2, T12, and T8 spinous processes and transverse processes. Surface, linear-enveloped electromyographic (sEMG) recordings were obtained from electrodes located bilaterally over the L5 and L3 erector spinae musculature. Force-time and sEMG time histories were recorded simultaneously to quantify the association between spinal manipulative therapy mechanical and electromyographic response. A total of 1600 sEMG recordings were analyzed from 20 spinal manipulative therapy treatments, and comparisons were made between segmental level, segmental contact point (spinous vs. transverse processes), and magnitude of the reflex response (peak-peak [p-p] ratio and relative mean sEMG). Positive sEMG responses were defined as >2.5 p-p baseline sEMG output (>3.5% relative mean sEMG output). SEMG threshold was further assessed for correlation of patient self-reported pain and disability. Results: Consistent, but relatively localized, reflex responses occurred in response to the localized, brief duration MFMA thrusts delivered to the thoracolumbar spine and SI joints. The time to peak tension (sEMG magnitude) ranged from 50 to 200 msec, and the reflex response times ranged from 2 to 4 msec, the latter consistent with intraspinal conduction times. Overall, the 20 treatments produced systematic and significantly different L5 and L3 sEMG responses, particularly for thrusts delivered to the lumbosacral spine. Thrusts applied over the transverse processes produced more positive sEMG responses (25.4%) in comparison with thrusts applied over the spinous processes (20.6%). Left side thrusts and right side thrusts over the transverse processes elicited positive contralateral L5 and L3 sEMG responses. When the data were examined across both treatment level and electrode site (L5 or L3, L or R), 95% of patients showed positive sEMG response to MFMA thrusts. Patients with frequent to constant low back pain symptoms tended to have a more marked sEMG response in comparison with patients with occasional to intermittent low back pain. Conclusions: This is the first study demonstrating neuromuscular reflex responses associated with MFMA spinal manipulative therapy in patients with low back pain. Noteworthy was the finding that such mechanical stimulation of both the paraspinal musculature (transverse processes) and spinous processes produced consistent, generally localized sEMG responses. Identification of neuromuscular characteristics, together with a comprehensive assessment of patient clinical status, may provide for clarification of the significance of spinal manipulative therapy in eliciting putative conservative therapeutic benefits in patients with pain of musculoskeletal origin.

Sensory motor control of the lower back: implications for rehabilitation, Ebenbichler, G, Oddsson, L, Kollmitzer, J, Erim, Z.

Med Sci Sports Exer, 2001;33:1889-98

This paper described a series of studies that have been done investigating the surface electromyography (SEMG) fatigue pattern of the back muscles during submaximal contraction. SEMG changes correlated with erector muscle fatigue, validating the subjective erector muscle endurance tests against the objective SEMG. Given the results of this study, a larger double-blind study of SEMG evaluation compared to manual muscle testing could be done, wherein back muscles strength and endurance time during testing are measured before and after a course of chiropractic care.

Ischemia causes muscle fatigue, Murthy, G, Hargens, A, Lehman, S, Rempel, D.

J Orthop Res, 2001;19:436-440

The purpose of this investigation was to determine whether ischemia, which reduces oxygenation in the extensor carpi radialis (ECR) muscle, causes a reduction in muscle force production. In eight subjects, muscle oxygenation (TO₂) of the right ECR was measured noninvasively and continuously using near infrared spectroscopy (NIRS) while muscle twitch force was elicited by transcutaneous electrical stimulation (1 Hz, 0.1 ms). Baseline measurements of blood volume, muscle oxygenation and twitch force were recorded continuously, then a tourniquet on the upper arm was inflated to one of five different pressure levels: 20, 40, 60 mm Hg (randomized order) and diastolic (69 ± 9.8 mm Hg) and systolic (106 ± 12.8 mm Hg) blood pressures. Each pressure level was maintained for 3–5 min, and was followed by a recovery period sufficient to allow measurements to return to baseline. For each respective tourniquet pressure level, mean TO₂ decreased from resting baseline (100% TO₂) to 99 ± 1.2% (SEM), 96 ± 1.9%, 93 ± 2.8%, 90 ± 2.5%, and 86 ± 2.7%, and mean twitch force decreased from resting baseline (100% force) to 99 ± 0.7% (SEM), 96 ± 2.7%, 93 ± 3.1%, 88 ± 3.2%, and 86 ± 2.6%. Muscle oxygenation and twitch force at 60 mm Hg tourniquet compression and above were significantly lower (P<0.05) than baseline value. Reduced twitch force was correlated in a dose-dependent manner with reduced muscle oxygenation (r=0.78,P<0.001). Although the correlation does not prove causation, the results indicate that ischemia leading to a 7% or greater reduction in muscle oxygenation causes decreased muscle force production in the forearm extensor muscle. Thus, ischemia associated with a modest decline in TO₂ causes muscle fatigue.

Physiology of human lymphatic contractility: a historical perspective,
Gashev AA, Zawieja DC.

Lymphology. 2001 Sep;34(3):124-34.

Abstract: The lymphatic system is a transport system that has important roles in fluid/macromolecule homeostasis, lipid absorption, metastasis and immune function. It accomplishes these roles via the generation of a regulated lymph circulation which is dependent upon valves and pumps to overcome the normal fluid pressure gradients. Lymphatic contractility plays crucial roles in the regulation and generation of lymph transport. Whereas our understanding of lymphatic contractility in humans is somewhat limited, a number of studies both in situ and in vitro have provided important insights into the presence and modulation of lymphatic contractility. These studies have clearly demonstrated that lymphatic vessels from a number of different human tissues possess both tonic and phasic changes in contractility. These changes in contractility are presumably involved in the generation and regulation of lymph flow. It has been shown that human lymphatic contractility can be influenced by a number of neural and humoral agents as a means to control lymph transport. However our understanding of the physical and chemical factors which regulate both the spontaneous pumping activity and the vessel tone are more limited. An understanding of the factors which regulate human lymph transport could provide valuable information on human biology that could be of benefit to the treatment and prevention of diseases.

Spinal manipulation causes variable spine kinematic and trunk muscle electromyographic responses, Lehman GJ, McGill SM.

Clin Biomech (Bristol, Avon). 2001 May;16(4):293-9.

STUDY DESIGN: Analytic cohort with a convenience sample in a research clinic. OBJECTIVES: To determine the influence of a spinal manipulation on trunk kinematics and associated trunk myoelectric activity. SUMMARY OF BACKGROUND: While the mechanism of spinal manipulation is unknown, it has been theorized to influence spinal range of motion and trunk muscle activity. METHODS: Trunk kinematics were measured in low back pain patients (n = 14) during simple range of motion tasks in three planes, while trunk muscle electromyogram signals were recorded bilaterally from paraspinal and abdominal musculature. Kinematics and electromyogram signals were assessed pre-post manipulation. Electromyogram activity was also assessed pre-post manipulation during quiet stance. RESULTS: While no consistent kinematic or electromyographic changes occurred following manipulation across the population, individual changes were observed. The largest changes (> 6 degrees ) in range of motion occurred in the sagittal plane of three patients experiencing the greatest amount of pain. During quiet stance 17 muscles across all subjects exhibited changes in muscle activity following manipulation. Sixteen of those changes were decreases in muscle amplitude. CONCLUSIONS: This study offers some preliminary data on the short-term effects of manipulation on lumbar range of motion and dynamic electromyogram. The findings suggest that the response to manipulation is variable and dependent on the individual, with no change in some to the largest changes seen in the more pained patients. Relevance. Basic science investigations into the mechanisms and biomechanical influences of spinal manipulation are few. This study attempts to address issues of measureable functional change with manipulative therapy.

Comment: This study shows that measurable changes in muscle function occur immediately after spinal manipulation.

Prevalence of nonmusculoskeletal complaints in chiropractic practice: report from a practice-based research program, Hawk C, Long CR, Boulanger KT.

-- Palmer Center for Chiropractic Research, Davenport, Iowa 52803, USA.

J Manipulative Physiol Ther. 2001 Mar-Apr;24(3):157-69.

OBJECTIVE: To identify patient and practice characteristics that might contribute to people's seeking chiropractic care for nonmusculoskeletal complaints. DESIGN: This was a cross-sectional study conducted through the methods of practice-based research. SETTING: Data were collected in 1998--1999 in chiropractic offices in the United States, Canada, and Australia; data were managed by a practice-based research office operating in a chiropractic research center. POPULATION: The subjects were new and established patients of all ages who visited the participating offices during a designated data collection week. DATA ANALYSIS: Multiple logistic regression was used to examine factors associated with patients' presenting for nonmusculoskeletal chief complaints. Pearson's chi(2) test was used to examine associations among practice variables and the proportion of patients with nonmusculoskeletal chief complaints. RESULTS: A total of 7651 patients of 161 chiropractors in 110 practices in 32 states and 2 Canadian provinces participated; data from 2 Australian practices were included in the totals but not in the analysis. Nonmusculoskeletal complaints accounted for 10.3% of the chief complaints. The following characteristics made patients more likely to present with nonmusculoskeletal chief complaints: being less than 14 years of age (adjusted odds ratio [AOR], 6.9; 95% CI, 5.2--9.1); being female (AOR, 1.5; CI, 1.3--1.8); presenting in a small town/rural location (AOR, 1.9; CI, 1.3--2.7); reporting more than 1 complaint, especially nonmusculoskeletal complaints (AOR, 4.9; CI, 3.9--6.0); having received medical care for the chief complaint (AOR, 3.4; CI, 2.9--4.1); and having first received chiropractic care before 1960 (AOR, 1.7; CI, 1.1--2.4). Practices with the highest proportion of patients with nonmusculoskeletal chief complaints (>17%) were less likely to accept insurance and more likely to be in locations with populations greater than 100,000. They used the most common chiropractic adjustive techniques less frequently and used more nonadjustive procedures, especially diet/nutrition counseling, nutritional supplementation, herbal preparations, naturopathy, and homeopathy. CONCLUSIONS: Drawing on practices with the patient and practice characteristics identified in this study to conduct outcomes studies on nonmusculoskeletal conditions is a possible direction for future research.

Comment: Applied kinesiologists theorize that specific muscles are associated with specific areas of the body. There are organ-muscle, gland-muscle, meridian-muscle, spine-muscle, and reflex-muscle relationships. (The relationships between specific spinal nerves and specific muscles are taught in neurology textbooks.) AK MMT offers a simple, non-invasive method of functional diagnosis that incorporates many other chiropractic, osteopathic, cranial, nutritional, manual medicine, and Traditional Chinese Medicine assessment methods, all of which are based on the traditional and foundational principles of chiropractic health care. AK combines many existing therapies into one inseparable system of health care, making AK a foundation stone for non-crisis care functional medicine.

Comparison of effects of spinal manipulation and massage on motoneuron excitability, Dishman J, Bulbulian R.

Electromyogr Clin Neurophysiol. 2001;41:97-106

Abstract: The purpose of this study was to compare the magnitude and duration of motoneuron inhibition occurring as a sequel to spinal manipulation or paraspinal and limb massage. The physiologic mechanisms involved in spinal manipulative therapy and massage therapy are largely unknown. One possible hypothesis is based upon the theory that these two distinct and different modalities may attenuate the activity of alpha motoneurons. Both modalities have been reported to produce short-term inhibition of motoneurons. Asymptomatic volunteers were randomly assigned to either a spinal manipulation, massage, or control group. Baseline tibial nerve H-reflex amplitudes were obtained prior to the application of either lumbosacral spinal manipulation or paralumbar and limb massage. Post-interventional H-reflex recordings were recorded immediately following the application of either modality. Spinal manipulation significantly (p < 0.05) attenuated alpha motoneuronal activity immediately post-therapy, as measured by the amplitude of the tibial nerve H-reflex. Massage subjects exhibited no significant reduction in motoneuronal activity immediately following administration. Spinal manipulation produced a transient attenuation of alpha motoneuronal excitability. Paraspinal and limb massage did not inhibit the motoneuron pool as measured immediately post-therapy. These findings support the supposition that spinal manipulation procedures lead to short-term inhibitory effects on motoneuron excitability to a greater magnitude than massage.

Relationship between hip muscle imbalance and occurrence of low back pain in collegiate athletes: a prospective study, Nadler SF,

Malanga GA, Feinberg JH,

Prybicien M, Stitik TP, DePrince M.

Am J Phys Med Rehabil. 2001 Aug;80(8):572-7.

OBJECTIVE: To assess whether athletes with strength imbalance of the hip musculature would be more likely to require treatment for low back pain (LBP) over the ensuing year. DESIGN: The study population included 163 National Collegiate Athletic Association Division I college athletes (100 males and 63 females) undergoing preparticipation sports physicals. Institutional review board approval was obtained to acquire and analyze hip muscle strength data. A commercially available dynamometer (Chatillon, Lexington, KY) incorporated into a specially designed anchoring station was used for testing the hip extensors and abductors. The maximum force generated for the hip abductors and extensors was used to calculate a percentage difference between the right and left hip extensors and abductors. Treatment of athletes by the athletic trainers for LBP unrelated to blunt trauma over the ensuing year was recorded. RESULTS: Of all athletes, 5 of 63 females and 8 of 100 males required treatment for LBP. Logistic regression analysis indicated that for female athletes, the percentage difference between the right and left hip extensors was predictive of whether treatment for LBP was required over the ensuing year (P = 0.05). There was no significant association noted for the percentage difference between the right and left hip abductors in females and for the percentage difference between both the right and left hip abductors and right and left hip extensors in males requiring treatment for LBP. CONCLUSIONS: These data support our results from our previous cohort study, adding validity to the concept of hip muscle imbalance being associated with LBP occurrence in female athletes. This research further supports the need for the assessment and treatment of hip muscle imbalance in individuals with LBP.

Comment: The correlation between “inhibited” or “weak” MMT findings and low back pain has been established in much of the research literature. This paper shows that there is a construct validity and reliability in employing MMT testing in patients with low back pain.

Measuring knee extensor muscle strength, Bohannon RW.

-- Department of Physical Therapy, School of Allied Health, University of Connecticut, Storrs 06269-2101, USA.

Am J Phys Med Rehabil. 2001 Jan;80(1):13-8.

OBJECTIVE: To compare manual muscle test with hand-held dynamometer measurements of knee extension strength. A secondary analysis of measurements (n = 256 knees) from 128 acute rehabilitation patients was performed. DESIGN: Knee extensor muscle testing was conducted according to the technique of Hislop and Montgomery; 0 to 5 grades were converted to an expanded 0 to 12 scale. Dynamometry was used to measure the isometric knee extension force with 'gravity eliminated.' RESULTS: Manual muscle test and dynamometer measures were highly correlated (r = 0.768; P < 0.001); the correlation was higher when the quadratic nature of the relationship was taken into account (R = 0.887; P < 0.001). Although the dynamometer forces that were associated with different manual muscle test grades differed overall (F = 67.736; P < 0.001), the forces associated with some of the higher grades did not differ statistically. CONCLUSIONS: These findings reinforce the convergent construct validity of the manual muscle test and dynamometry measurements but challenge the discriminant construct validity of manual muscle testing. An alternative manual muscle testing grading scheme is suggested that provides for discriminant validity and retains convergent validity.

Effect of knee joint effusion on quadriceps and soleus motoneuron pool excitability, Hopkins JT, Ingersoll CD, Krause BA, Edwards JE, Cordova ML.

Med Sci Sports Exerc, 2001 Jan;33(1):123-6.

PURPOSE: To examine changes in quadriceps and soleus MN pool activity resulting from knee joint effusion over a 4-h period and assess the relationship between the muscles. METHODS: A repeated measures before-after trial design was used for this study. Eight, neurologically sound volunteers (age 23.3+/-2.1 yr, height 171.8+/-15.9 cm, mass 65.5+/-17.7 kg) participated in this study. An area superomedial to the patella was cleaned and anesthetized, and 30 mL of sterile saline was injected into the knee joint capsule to mimic mechanical joint effusion. The Hoffman reflex (H-reflex) was elicited by applying a percutaneous stimulus to the appropriate nerve and recording the response through surface electromyography. Soleus and vastus medialis H-reflex measures were collected from each volunteer before, at 30 min, 90 min, 150 min, and 210 min intervals over a 4-h period after knee effusion. RESULTS: All soleus H-reflex measures after effusion (30 min 5.89+/-0.92 V; 90 min 6.16+/-0.48 V; 150 min 6.59+/-0.50 V; 210 min 6.70+/-0.56 V) were increased in relation to the preeffusion measure (5.01+/-0.79 V). All vastus medialis H-reflex measures after effusion (30 min 4.23+/-0.94 V; 90 min 4.15 +/-1.11 V; 150 min 4.16+/-0.57 V; and 210 min 4.99+/-1.23) were decreased in relation to the preeffusion measure (5.88+/-1.44 V; P < or = 0.05). CONCLUSIONS: Afferent activity from the knee joint capsule resulted in an inhibitory effect on the vastus medialis and a facilitatory effect on the soleus. Facilitation of the soleus in cooperation with other lower extremity musculature could be a mechanism for compensation of the inhibited quadriceps to maintain lower kinetic chain function.

Delayed onset of electromyographic activity of vastus medialis obliquus relative to vastus lateralis in subjects with patellofemoral pain syndrome,
Cowan SM, Bennell KL, Hodges PW, Crossley KM, McConnell J.

Arch Phys Med Rehabil. 2001 Feb;82(2):183-9.

OBJECTIVE: To determine whether electromyographic (EMG) onsets of vastus medialis obliquus (VMO) and vastus lateralis (VL) are altered in the presence of patellofemoral pain syndrome (PFPS) during the functional task of stair stepping. DESIGN: Cross-sectional. SETTING: University laboratory. PATIENTS: Thirty-three subjects with PFPS and 33 asymptomatic controls. INTERVENTIONS: Subjects ascended and descended a set of stairs-2 steps, each 20-cm high-at usual stair-stepping pace. EMG readings of VMO and VL taken on middle stair during step up (concentric contraction) and step down (eccentric contraction). MAIN OUTCOME MEASURES: Relative difference in onset of surface EMG activity of VMO compared with VL during a stair-stepping task. EMG onsets were determined by using a computer algorithm and were verified visually. RESULTS: In the PFPS population, the EMG onset of VL occurred before that of VMO in both the step up and step down phases of the stair-stepping task (p <.05). In contrast, no such differences occurred in the onsets of EMG activity of VMO and VL in either phase of the task for the control subjects. CONCLUSION: This finding supports the hypothesized relationship between changes in the timing of activity of the vasti muscles and PFPS. This finding provides theoretical rationale to support physiotherapy treatment commonly used in the management of PFPS.

Quantitative study of muscle spindles in suboccipital muscles of human fetuses, Kulkarni V, Chandy MJ, Babu KS.

Neurol India. 2001 Dec;49(4):355-9.

Abstract: The proprioceptive inputs from the cervical musculature play an important role in head-eye co-ordination and postural processes. Deep cervical muscles in humans are shown to have high spindle content. The density, distribution and morphology of muscle spindles were studied in superior oblique capitis, inferior oblique capitis and rectus capitis posterior major and minor three small suboccipital muscles. The muscles were obtained, post-mortem from stillborn human foetus. The spindle density was calculated as the ratio of mean spindle content to the mean wet weight of that muscle in grams. The distribution and arrangement of spindles within the muscle and their arrangement was studied. The spindle density of superior oblique muscle was found to be 190, that of inferior oblique was 242 and the rectus capitis posterior contained 98 spindles per gram of muscle. No tendon organs were seen. The serial transverse sections of inferior oblique muscle revealed muscle spindles of varying sizes, length varying between 100-650 microns and, diameter 50-250 microns. A complex parallel arrangement of group of large spindles were seen in the belly of the inferior oblique muscle, while the polar regions contain few small isolated spindles. The relevance of such high spindle receptor content in these tiny muscles is discussed.

Comment: Postural instability in children may contribute to various learning and behavior problems, including attention deficit disorder and complex developmental disorders. Many children who fall within these categories will demonstrate significant posture and balance dysfunctions when carefully tested. More often than not, the postural deficit is related to a biomechanical dysfunction, which can be addressed with the proper manipulative therapy.More than 40% of the sensors relaying proprioceptive information are found in the cervical region. The suboccipital area is critically important to proprioception, and it is the area most frequently faulted in proprioceptive examination and treatment. Grostic, Sweat, and other upper cervical chiropractic researchers have shown that joint dysfunctions of even less than 1 mm can disturb cerebellar function, muscle function, body posture, leg length inequalities, and nociception.

Attachments from the Spinal Dura to the Ligamentum Nuchae: Incidence, MRI Appearance, and Strength of Attachment, Kenin S, Humphreys BK, Hubbard B, Cramer GD

Proceedings of the 2000 International Conference of Spinal Manipulation  2000;Sept:202-4

Abstract: The identification of attachments to the posterior spinal dura from the surrounding tissues in the cranio-cervical region by Von Lanz in 1929, may provide the key towards a better understanding of underlying mechanisms involved in chronic benign headaches as well as neck pain of unknown etiology.  The recent findings of connective tissue attachments to the cervical spinal dura from muscles, ligament, and osseous elements have sparked increasing interest among clinicians and anatomists.  However, studies of a large number of specimens or those evaluating the MRI appearance of these attachments have never been published.  This study evaluated these attachments in 30 cadaveric spines and then correlated the MRI appearance of the attachments to their anatomic appearance on 4 of the specimens.

This study identified a consistent connective tissue complex arising from within the substance of the ligamentum nuchae, between the occiput and axis, giving rise to 3 connective tissue bridges.  Two of the connective tissue bridges attached to the posterior spinal dura while the third linked the rectus capitis posterior minor muscle to the ligamentum nuchae.  Of significance were: (1) The attachment between the ligamentum nuchae and dura between C1-C2 are quite robust.  (2) The attachments between the rectus capitis posterior minor and ligamentum nuchae usually exist.  (3) The attachments between the ligamentum nuchae and dura mater can be identified on MRI scans.  These attachments may have clinical significance in cervicogenic headache, vertigo, and flexion-extension (whiplash) injuries, making their MRI appearance clinically important.

Conservative lower back treatment reduces inhibition in knee-extensor muscles: a randomized controlled trial,Suter, E., McMorland, G., Herzog, W., Bray, R.

J Manipulative Physiol Ther, 2000;23:76-80

(http://www.journals.elsevierhealth.com/periodicals/ymmt/article/PIIS016147540090071X/abstract)

Background: Knee-joint pathologies, such as anterior knee pain (AKP), are associated with strength deficits and reduced activation of the knee extensors, which is referred to as muscle inhibition (MI). MI is thought to prevent full functional recovery, and treatment modalities that help to reduce or eliminate MI appear necessary for successful rehabilitation. Clinical observations suggest that AKP is typically associated with sacroiliac (SI) joint dysfunction. It is unknown whether Sl-joint dysfunction contributes toknee-extensor deficits and whether correction of SI-joint dysfunction alleviates MI. Objective: The objective of this study was to assess whether conservative low back treatment reduces lower limb MI. Study design: In a randomized, controlled, double-blind study the effects of conservative lower back treatment on knee-extensor strength and MI were evaluated in patients with AKP. Methods: Twenty-eight patients with AKP were randomly assigned to either a treatment or a control group. After a lower back functional assessment, the treatment group received a conservative treatment in the form of a chiropractic spinal manipulation aimed at correcting SI-joint dysfunction. The control group underwent a lower back functional assessment but received no joint manipulation. Before and after the manipulation or the lower back functional assessment, knee-extensor moments, MI, and muscle activation during full effort, isometric knee extensions were measured. Results: Patients showed substantial MI in both legs. Functional assessment revealed SI-joint dysfunction in all subjects (23 symptomatic and 5 asymptomatic). After the SI-joint manipulation, a significant decrease in MI of 7.5% was observed in the involved legs of the treatment group. MI did not change in the contralateral legs of the treatment group or the involved and contralateral legs of the control group. There were no statistically significant changes in knee-extensor moments and muscle activation in either group. Conclusions: The results of this study suggest that SI-joint manipulation reduces knee-extensor MI. Spinal manipulation may possibly be an effective treatment of MI in the lower limb musculature.

Muscle response pattern to sudden trunk loading in healthy individuals and in patients with chronic low back pain, Radebold A, Cholewicki J, Panjabi MM, Patel TC.

Spine, 2000 Apr 15;25(8):947-54.

STUDY DESIGN: A quick-release method in four directions of isometric trunk exertions was used to study the muscle response patterns in 17 patients with chronic low back pain and 17 matched control subjects. OBJECTIVES: It was hypothesized that patients with low back pain would react to sudden load release with a delayed muscle response and would exhibit altered muscle recruitment patterns. SUMMARY OF BACKGROUND DATA: A delay in erector spinae reaction time after sudden loading has been observed in patients with low back pain. Muscle recruitment and timing pattern play an important role in maintaining lumbar spine stability. METHODS: Subjects were placed in a semiseated position in an apparatus that provided stable fixation of the pelvis. They exerted isometric contractions in trunk flexion, extension, and lateral bending. Each subject performed three trials at two constant force levels. The resisted force was suddenly released with an electromagnet and electromyogram signals from 12 trunk muscles were recorded. The time delay between the magnet release and the shut-off or switch-on of muscle activity (reaction time) was compared between two groups of subjects using two-factor analysis of variance. RESULTS: The number of reacting muscles and reaction times averaged over all trials and directions showed the following results: For healthy control subjects a shut-off of agonistic muscles (with a reaction time of 53 msec) occurred before the switch-on of antagonistic muscles (with a reaction time of 70 msec). Patients exhibited a pattern of co-contraction, with agonists remaining active (3.4 out of 6 muscles switched off) while antagonists switched on (5.3 out of 6 muscles). Patients also had longer muscle reaction times for muscles shutting off (70 msec) and switching on (83 msec) and furthermore, their individual muscle reaction times showed greater variability. CONCLUSIONS: Patients with low back pain, in contrast to healthy control subjects, demonstrated a significantly different muscle response pattern in response to sudden load release. These differences may either constitute a predisposing factor to low back injuries or a compensation mechanism to stabilize the lumbar spine.

Comment: Dr. Panjabi is the world’s most published human biomechanical researcher, with 263 published articles to date. The hypothesis he and the other authors of this paper present places the functionality of muscles, as both a cause and a consequence in chronic back pain patients, at the center of a sequence of events that ultimately results in back pain. The role of the muscular system, as “the stabilizing system of the spine,” has been investigated by Dr. Panjabi in numerous other papers.

Cervical muscle dysfunction in the chronic whiplash associated disorder grade II (WAD-II),
Nederhand MJ, IJzerman MJ, Hermens HJ, Baten CT, Zilvold G.

Spine. 2000 Aug 1;25(15):1938-43.

STUDY DESIGN: In a cross-sectional study, surface electromyography measurements of the upper trapezius muscles were obtained during different functional tasks in patients with a chronic whiplash associated disorder Grade II and healthy control subjects. OBJECTIVES: To investigate whether muscle dysfunction of the upper trapezius muscles, as assessed by surface electromyography, can be used to distinguish patients with whiplash associated disorder Grade II from healthy control subjects. SUMMARY OF BACKGROUND INFORMATION: In the whiplash associated disorder, there is need to improve the diagnostic tools. Whiplash associated disorder Grade II is characterized by the presence of "musculoskeletal signs." Surface electromyography to assess these musculoskeletal signs objectively may be a useful tool. METHODS: Normalized smoothed rectified electromyography levels of the upper trapezius muscles of patients with whiplash associated disorder Grade II (n = 18) and healthy control subjects (n = 19) were compared during three static postures, during a unilateral dynamic manual exercise, and during relaxation after the manual exercise. Coefficients of variation were computed to identify the measurement condition that discriminated best between the two groups. RESULTS: The most pronounced differences between patients with whiplash associated disorder Grade II and healthy control subjects were found particularly in situations in which the biomechanical load was low. Patients showed higher coactivation levels during physical exercise and a decreased ability to relax muscles after physical exercise. CONCLUSIONS: Patients with whiplash associated disorder Grade II can be distinguished from healthy control subjects according to the presence of cervical muscle dysfunction, as assessed by surface electromyography of the upper trapezius muscles. Particularly the decreased ability to relax the trapezius muscles seems to be a promising feature to identify patients with whiplash associated disorder Grade II. Assessment of the muscle (dys)function by surface electromyography offers a refinement of the whiplash associated disorder classification and provides an indication to a suitable therapeutic approach.

Comment: This is a very important paper for AK. In terms of the etiology of symptoms from chronic whiplash disorders, this study suggests that the performance of the upper trapezius muscle is an invaluable diagnostic for musculoskeletal involvement in chronic whiplash disorders than many of the other previous findings used to diagnose and treat this problem. The evaluation and treatment of the upper trapezius muscle dysfunction is a standard part of AK therapy.

Motor control problems in patients with spinal pain: a new direction for therapeutic exercise, Jull GA, Richardson CA.

J Manipulative Physiol Ther, 2000 Feb;23(2):115-7.

Abstract: Recent research into muscle dysfunction in patients with low back pain has led to discoveries of impairments in deep muscles of the trunk and back. These muscles have a functional role in enhancing spinal segmental support and control. The muscle impairments are not those of strength but rather problems in motor control. These findings call for a different approach in therapeutic exercise, namely a motor learning exercise protocol. The specific exercise approach has an initial focus on retraining the co-contraction of the deep muscles (i.e., the transversus abdominis and lumbar multifidus). Initial clinical trials point to the effectiveness of the approach in patients with both acute and chronic low back pain in terms of reducing the neuromuscular impairment and in control of pain.

Comment: This study elegantly demonstrates that sensory and motor function is integrated, and that improper sequencing of muscle groups results in disjointed movement and pain. AK has argued from its founding that postural control is dependent upon the ability of the individual to properly interpret sensory information and execute an appropriate motor response. This study also demonstrates that both acute and chronic low back pain recovers more swiftly with specific treatments to the dysfunctional muscles.

Use of a mental rotation reaction-time paradigm to measure the effects of upper cervical adjustments on cortical processing: a pilot study, Kelly DD, Murphy BA, Backhouse DP.

J Manipulative Physiol Ther. 2000 May;23(4):246-51.

OBJECTIVES: To investigate the potential usefulness of a mental rotation paradigm in providing an objective measure of spinal manipulative therapy. To determine if cortical processing, as indicated by response time to a mental rotation reaction-time task, is altered by an upper cervical toggle recoil adjustment. DESIGN: Prospective, double-blind, randomized, controlled trial. SETTING: Chiropractic college clinical training facility. PARTICIPANTS: Thirty-six chiropractic student volunteers with clinical evidence of upper cervical joint dysfunction. INTERVENTION: Participants in the experimental group received a high-velocity, low-amplitude upper cervical adjustment. A non-intervention group was used to control for improvement in the mental rotation task as a result of practice effects. Outcome measures: Reaction time was measured for randomly varying angular orientations of an object appearing either as normal or mirror-reversed on a computer screen. RESULTS: The average decrease in mental rotation reaction time for the experimental group was 98 ms, a 14.9% improvement, whereas the average decrease in mental rotation reaction time for the control group was 58 ms, an 8. 0 improvement. The difference scores after the intervention time were significantly greater for the experimental group compared with the control group, as indicated by a one-tailed, 2-sample, equal variance Student t test, (P < 05). CONCLUSION: The results of this study have demonstrated a significant improvement in a complex reaction-time task after an upper cervical adjustment. These results provide evidence that upper cervical adjustment may affect cortical processing.

Comment: This study demonstrates another investigation into the potential motor control, proprioceptive response, and functional improvements resulting from chiropractic treatments.

Reflex effects of subluxation: the autonomic nervous system, Budgell, B.S.

J Manipulative Physiol Ther, 2000;23(2):104-106

(http://www.journals.elsevierhealth.com/periodicals/ymmt/article/PIIS0161475400900769/abstract)

Background: The collective experience of the chiropractic profession is that aberrant stimulation at a particular level of the spine may elicit a segmentally organized response, which may manifest itself in dysfunction within organs receiving autonomic innervation at that level. This experience is at odds with classic views of neuroscientists about the potential for somatic stimulation of spinal structures to affect visceral function. Objective: To review recent findings from basic physiologic research about the effects of somatic stimulation of spinal structures on autonomic nervous system activity and the function of dependent organs. Data source: Findings were drawn from a major recent review of the literature on the influences of somatic stimulation on autonomic function and from recent original physiologic studies concerning somatoautonomic and spinovisceral reflexes.

Conclusions: Recent neuroscience research supports a neurophysiologic rationale for the concept that aberrant stimulation of spinal or paraspinal structures may lead to segmentally organized reflex responses of the autonomic nervous system, which in turn may alter visceral function.

Comment: Within the spinal cord is the anterior and posterior horn. These horns are divided into five different lamina. The spinal tracts go up and down the spinal cord within these lamina. Lamina 2 holds the spinal tracts that supply and control the visceral organs. Lamina 5 holds the spinal tracts that control the muscles and the skin, carrying the nerve impulses that come from the muscles and skin. Neuro-anatomists have discovered a neuron that connects lamina 2 to lamina 5; it is called the alpha motor neuron. The alpha motor neuron connecting lamina 2 and 5 means that stimulation to the skin or a muscle will simultaneously affect the organs and vice versa. This is neurological, anatomical proof that the muscles, organs and skin, are connected together by the alpha motor neuron. AK physicians have found that they cannot treat one part of the body without affecting another part of the body, which validates what chiropractors and applied kinesiologists do. The MMT makes these types of connections (muscle-organ, muscle-gland, muscle-joint) evident to the patient.

Abnormalities of the soleus H-reflex in lumbar spondylolisthesis: a possible early sign of bilateral S1 root dysfunction, Mazzocchio R, Scarfo GB, Cartolari R, Bolognini A, Mariottini A, Muzii VF, Palma L.

J Spinal Disord. 2000 Dec;13(6):487-95.

Abstract: Using routine electrodiagnostic procedures, the authors searched for physiologic evidence of nerve root compromise in patients with chronic mechanical perturbation to the lumbar spine. They examined 37 patients with spondylolisthesis and various degrees of degenerative changes in the lumbar canal. Clinical and neurophysiologic findings were compared with data obtained from 36 healthy persons. The soleus H-reflex appeared to be a sensitive indicator of sensory fiber compromise at the S1 root level, because changes correlated well with the focal sensory signs and preceded clinical and electromyographic signs of motor root involvement. When these occurred, the clinical findings were consistent with a more severe nerve root deficit and with radiographic evidence of neural compression. The greater sensitivity of the soleus H-reflex may be related to the pathophysiologic events that occur at the lesion site.

Spinal reflex attenuation associated with spinal manipulation, Dishman JD, Bulbulian R.

 

Spine, 2000 Oct 1;25(19):2519-24;discussion 2525.

STUDY DESIGN: This study evaluated the effect of lumbosacral spinal manipulation with thrust and spinal mobilization without thrust on the excitability of the alpha motoneuronal pool in human subjects without low back pain. OBJECTIVES: To investigate the effect of high velocity, low amplitude thrust, or mobilization without thrust on the excitability of the alpha motoneuron pool, and to elucidate potential mechanisms in which manual procedures may affect back muscle activity. SUMMARY OF BACKGROUND DATA: The physiologic mechanisms of spinal manipulation are largely unknown. It has been proposed that spinal manipulation may reduce back muscle electromyographic activity in patients with low back pain. Although positive outcomes of spinal manipulation intervention for low back pain have been reported in clinical trials, the mechanisms involved in the amelioration of symptoms are unknown. METHODS: In this study, 17 nonpatient human subjects were used to investigate the effect of spinal manipulation and mobilization on the amplitude of the tibial nerve Hoffmann reflex recorded from the gastrocnemius muscle. Reflexes were recorded before and after manual spinal procedures. RESULTS: Both spinal manipulation with thrust and mobilization without thrust significantly attenuated alpha motoneuronal activity, as measured by the amplitude of the gastrocnemius Hoffmann reflex. This suppression of motoneuronal activity was significant (P < 0.05) but transient, with a return to baseline values exhibited 30 seconds after intervention. CONCLUSIONS: Both spinal manipulation with thrust and mobilization without thrust procedures produce a profound but transient attenuation of alpha motoneuronal excitability. These findings substantiate the theory that manual spinal therapy procedures may lead to short-term inhibitory effects on the human motor system.

Comment: This study demonstrates that there is an immediate effect upon the motor system after spinal manipulative therapy. This factor has been consistently demonstrated in AK, and measuring the effect upon the motor system is made after every manipulative treatment. Clinical conditions involving hypotonicity, spasticity or hypertonicity are attributed to pathophysiologic abnormalities in the motor neuron system, and this study measures this state.

Integrated jaw and neck function in man. Studies of mandibular and head-neck movements during jaw opening-closing tasks, Zafar H

Swed Dent J Suppl, 2000;(143):1-41.

Abstract: This investigation was undertaken to test the hypothesis of a functional relationship between the human temporomandibular and craniocervical regions. Mandibular and head-neck movements were simultaneously recorded in healthy young adults using a wireless optoelectronic system for three dimensional movement recording. The subjects were seated in an upright position without head support and were instructed to perform maximal jaw opening-closing movements at fast and slow speed. As a basis, a study was undertaken to develop a method for recording and analysis of mandibular and head-neck movements during natural jaw function. A consistent finding was parallel and coordinated head-neck movements during both fast and slow jaw opening-closing movements. The head in general started to move simultaneously with or before the mandible at the initiation of jaw opening. Most often, the head attained maximum velocity after the mandible. A high degree of spatiotemporal consistency of mandibular and head-neck movement trajectories was found in successive recording sessions. The head movement amplitude and the temporal coordination between mandibular and head-neck movements were speed related but not the movement trajectory patterns. Examination of individuals suffering from temporomandibular disorders and whiplash associated disorders (WAD) showed, compared with healthy subjects, smaller amplitudes, a diverse pattern of temporal coordination but a similar high degree of spatiotemporal consistency for mandibular and head-neck movements. In conclusion, the results suggest the following: A functional linkage exists between the human temporomandibular and craniocervical regions. Head movements are an integral part of natural jaw opening-closing. "Functional jaw movements" comprise concomitant mandibular and head-neck movements which involve the temporomandibular, the atlanto-occipital and the cervical spine joints, caused by jointly activated jaw and neck muscles. Jaw and neck muscle actions are elicited and synchronized by neural commands in common for both the jaw and the neck motor systems. These commands are preprogrammed, particularly at fast speed. In the light of previous observations of concurrent jaw and head movements during foetal yawning, it is suggested that these motor programs are innate. Neural processes underlying integrated jaw and neck function are invariant both in short- and long-term perspectives. Integrated jaw and neck function seems to be crucial for maintaining optimal orientation of the gape in natural jaw function. Injury to the head-neck, leading to WAD may derange integrated jaw-neck motor control and compromise natural jaw function.

Comment: In AK examination and treatment, the complexity of the TMJ apparatus is recognized. The TMJ is part of a complex system including the bones of the skull and cervical spine, the mandible and hyoid bone, the related muscle attachments and other soft tissues, and neurologic and vascular components. This complex is often referred to as the stomatognathic system. The use of AK methods, especially challenge and therapy localization, greatly assists the practitioner in finding concealed or hidden TMJ problems.

The craniocervical connection: a retrospective analysis of 300 whiplash patients with cervical and temporomandibular disorders, Friedman MH, Weisberg J.

Cranio. 2000 Jul;18(3):163-7.

Abstract: Because the concept of whiplash as a causative factor for temporomandibular disorders (TMD) is highly controversial, we decided to do a retrospective analysis of patients treated in our office who had sustained whiplash injuries and were treated for cervical and temporomandibular disorders. The records of 300 patients with TMD preceded by a motor vehicle accident were examined retrospectively. The most common presenting symptoms, in order, were: jaw pain, neck pain, post-traumatic headache, jaw fatigue, and severe temporomandibular joint (TMJ) clicking. The most common TMD diagnoses were: masseter trigger points, closing jaw muscle hyperactivity, TMJ synovitis, opening jaw muscle hyperactivity, and advanced TMJ disk derangement. Based primarily on the physical examination, we concluded that the TMJ and surrounding musculature should be examined similarly to other joints, with no preconceived notion that TMD pathology after whiplash is unlikely.

EMG and strength correlates of selected shoulder muscles during rotations of the glenohumeral joint, David G, Magarey ME, Jones MA, Dvir Z, Turker KS, Sharpe M.

Clin Biomech (Bristol, Avon). 2000 Feb;15(2):95-102.

OBJECTIVE: To identify activation patterns of several muscles acting on the shoulder joint during isokinetic internal and external rotation. DESIGN: Combined EMG and isokinetic strength analysis in healthy subjects. BACKGROUND: EMG studies of the shoulder region revealed intricate muscular activation patterns during elevation of the arm but no parallel studies regarding pure rotations of the joint could be located. METHODS: Fifteen (n=30 shoulders) young, asymptomatic male subjects participated in the study. Strength production during isokinetic concentric and eccentric internal and external rotations at 60 and 180 degrees /s was correlated with the EMG activity of the rotator cuff, biceps, deltoid and pectoralis major. Analysis of the smoothed EMG related to the timing of onset of the signal and to the normalized activity at the angle of the peak moment. Determination of the association between the EMG and the moment was based on strength ratios. RESULTS: Findings indicated that for both types of rotations, the rotator cuff and biceps were active 0.092+/-0.038-0.215+/-0.045 s prior to the initiation of the actual movement and 0.112-0.034 s prior to onset of deltoid and pectoralis major activity. These differences were significant in all of the eight conditions (P<0.05). In terms of the strength ratios, strong association was found between electrical activity and moment production in the subscapularis and infraspinatus (r(2)=0.95 and 0. 72, respectively) at the low and high angular velocities. CONCLUSIONS: Prior to actual rotation of the shoulder joint, normal recruitment of the rotator cuff and biceps is characterized by a non-specific presetting phase which is mainly directed at enhancing the joint 'stiffness' and hence its stability. Once movement is in progress, the EMG patterns of these muscles become movement specific and are correlated with the resultant moment. RELEVANCE: Muscular dysfunction relating to delayed onset activity or altered activation patterns, due to pain, perturbed mechanics or disturbed neural activation have been implicated as concomitant factors in other joint associated pathologies. Through highlighting the role of the rotator cuff in shoulder joint rotations, this study lends further support to the argument that a parallel situation may prevail with respect to shoulder joint dysfunction. This could lead to the development of rehabilitation protocols aimed specifically at redressing such dysfunction.

Muscle force measured using "break" testing with a hand-held myometer in normal subjects aged 20 to 69 years, Phillips BA, Lo SK, Mastaglia FL.

-- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Australian Neuromuscular Research Institute, Perth.

Arch Phys Med Rehabil. 2000 Oct;81(10):1442-3.

OBJECTIVE: To measure the strength of 17 muscle groups in the upper and lower extremities in a large group of healthy subjects using "break" testing with a hand-held myometer, and to examine the intrasession and intersession reliability of the testing protocol. SUBJECTS AND INSTRUMENTATION: A convenience sample of 20 men and 20 women in each decade of age from 20 to 69 years (n = 200) was tested using a Penny & Giles hand-held myometer. RESULTS: Reliability coefficients were >.85 for both intrasession and intersession reliability, except for the ankle dorsiflexors. Men exerted a significantly greater force than women for all muscle groups. Age, weight, and side of testing were significant predictors of force in the majority of muscle groups. The fifth percentile values, as the lower limit of normal, are reported separately for gender and side of testing for each decade of age. CONCLUSION: Using the testing protocol specified in this study, data from patients with various neuromuscular diseases may be compared with the appropriate gender- and age-matched normal data to accurately identify the presence of weakness.

Hand-held dynamometry reliability in persons with neuropathic weakness,
Kilmer DD, McCrory MA, Wright NC, Rosko RA, Kim HR, Aitkens SG.

-- Department of Physical Medicine and Rehabilitation, School of Medicine, University of California, Davis, USA.

Arch Phys Med Rehabil. 2000 Nov;81(11):1538-9.

OBJECTIVE: To determine test-retest reliability of hand-held dynamometry (HHD) in measuring strength of persons with neuropathic weakness. DESIGN: Intratester and intertester reliability of HHD-measured strength over a 7- to 10-day period. In addition, HHD knee strength was compared with criterion standard of fixed dynamometry (FD). SETTING: Human performance laboratory of a university. PARTICIPANTS: Convenience sample of ambulatory outpatients with Hereditary Motor and Sensory Neuropathy, Type I (HMSN) (n = 10) and able-bodied controls (CTL) (n = 11). MAIN OUTCOME MEASURE: Maximal isometric torque. RESULTS: Intratester intraclass correlation coefficients (ICCs) were high, generally ranging from .82 to .96 for HHD- and FD-measured strength for both HMSN and CTL groups. There were no significant differences between sessions for HHD-measured strength, while FD-measured strength was only significantly different for knee extension (p < .01). Intertester reliability was generally good for both HHD- and FD-measured strength, with ICCs ranging from .72 to .97 for HMSN and CTL groups. Exceptions were knee extensors and ankle dorsiflexors for the CTL group. Knee extensor strength was significantly lower measured by HHD compared with FD (p < .01), but knee flexor strength was similar for the two methods. CONCLUSION: HHD appears to be a reliable method to measure maximal isometric strength in persons with neurogenic weakness, and may be useful to quickly and objectively evaluate strength in the clinical setting.

The role of the motor system in spinal pain: implications for rehabilitation of the athlete following lower back pain,
Hodges PW.

J Sci Med Sport. 2000 Sep;3(3):243-53.

Abstract: The purpose of this review is to consider the role of the motor system in spinal pain. It is well accepted that spinal stability is dependent on the contribution of the muscular system. However, the ability of this system to satisfy the requirements of stability is dependent on its controller--the central nervous system (CNS). The CNS must predict the outcome of movements to plan appropriate strategies of muscle activity to meet the demands of internal and external forces, and initiate appropriate responses to unexpected disturbances. In addition, this complex control of stability must occur in conjunction with control of the trunk muscles for other functions, such as respiration. For the CNS to cope with athletic performance the coordination of these parameters must be streamlined. Yet evidence suggests that when spinal pain is present the strategies used by the CNS to control trunk muscles may be altered. The mechanism for these changes is poorly understood but may be due to changes at many levels of the CNS. For rehabilitation of the athlete with spinal pain it is critical that the motor control of stability is optimized. Furthermore, this must be coordinated with the multiple other functions of trunk muscles, including respiration.

Comment: This paper reviews precisely many of the central tenets of AK therapy.

Effects of acupuncture, cervical manipulation and NSAID therapy on dizziness and impaired head repositioning of suspected cervical origin: a pilot study, Heikkila H, Johansson M, Wenngren BI.

Man Ther. 2000 Aug;5(3):151-7.

Abstract: In a single-subject experiment undertaken on 14 consecutive patients, the effects of acupuncture, cervical manipulation, no therapy, and NSAID-percutan application on kinesthetic sensibility, dizziness/vertigo and pain were studied in patients with dizziness/vertigo of suspected cervical origin. The ability to perceive position of the head with respect to the trunk was studied. The effects of different forms of therapy-and none-on dizziness and neck pain were compared, using a 100 mm visual analogue scale (VAS). Active head relocation by subjects with dizziness was significantly less precise than in the control group. Manipulation was the only treatment to diminish the duration of dizziness/vertigo complaints during the past 7 days and increased the cervical range of motion. Both acupuncture and manipulation reduced dizziness/vertigo on the VAS scale and had positive effects on active head repositioning. Ketoprofen percutan application and acupuncture both alleviated pain. The results of this study would suggest that spinal manipulation may impact most efficiently on the complex process of proprioception and dizziness of cervical origin.

The pain of being sick: implications of immune-to-brain communication for understanding pain, Watkins LR, Maier SF.

Annu Rev Psychol. 2000;51:29-57.

Abstract: This review focuses on the powerful pain facilitatory effects produced by the immune system. Immune cells, activated in response to infection, inflammation, or trauma, release proteins called proinflammatory cytokines. These proinflammatory cytokines signal the central nervous system, thereby creating exaggerated pain as well as an entire constellation of physiological, behavioral, and hormonal changes. These changes are collectively referred to as the sickness response. Release of proinflammatory cytokines by immune cells in the body leads, in turn, to release of proinflammatory cytokines by glia within the brain and spinal cord. Evidence is reviewed supporting the idea that proinflammatory cytokines exert powerful pain facilitatory effects following their release in the body, in the brain, and in the spinal cord. Such exaggerated pain states naturally occur in situations involving infection, inflammation, or trauma of the skin, of peripheral nerves, and of the central nervous system itself. Implications for human pain conditions are discussed.

Comment: In AK it has been recognized for many years that inflammatory processes contribute to clinical syndromes in patients. The adrenal glands (which control pro- and anti-inflammatory processes in the body) have been an important component of AK diagnosis and treatment, as well as other anti-inflammatory treatment methods also (nutritional, dietary, meridian, structural, and others).

Nociceptive fingertip stimulation inhibits synergistic motoneuron pools in the human upper limb, Leis AA, Stokic DS, Fuhr P, Kofler M, Kronenberg MF, Wissel J, Glocker FX, Seifert C, Stetkarova I.

Neurology. 2000 Nov 14;55(9):1305-9.

BACKGROUND: Activation of distinct muscle groups organized in a stereotyped manner ("muscle synergies") is thought to underlie the production of movement by the vertebrate spinal cord. This results in movement with minimum effort and maximum efficiency. The question of how the vertebrate nervous system inhibits ongoing muscle activity is central to the study of the neural control of movement. OBJECTIVE: To investigate the strategy used by the human spinal cord to rapidly inhibit muscle activation in the upper limb. METHODS: The authors performed a series of experiments in 10 healthy subjects to assess the effect of nociceptive cutaneous stimulation on voluntarily contracting upper limb muscles. They recorded the electromyogram (EMG) with surface electrodes placed over various upper limb muscles. RESULTS: The authors found evidence of a simple inhibitory strategy that 1) was dependent on the intensity of the stimulus, 2) was maximally evoked when stimulation was applied to the fingertips, 3) preceded the earliest onset of voluntary muscle relaxation, and 4) produced inhibition of EMG activity in specific upper limb muscle groups. Nociceptive fingertip stimulation preferentially inhibited contraction of synergistic muscles involved in reaching and grasping (intrinsic hand muscles, forearm flexors, triceps) while having little effect on biceps or deltoid. CONCLUSIONS: Neural circuitry within the human spinal cord is organized to inhibit movement by rapidly deactivating muscles that constitute distinct muscle synergies. This strategy of selective and concurrent deactivation of the same basic elements that produce synergistic movement greatly simplifies motor control.

Comment: This paper describes nociception-induced motor neuron reflex inhibition at the dorsal horn of the spinal cord. The relationship between somatic injury and muscle weakness is demonstrated and explained here.

Short latency inhibition of human hand motor cortex by somatosensory input from the hand, Tokimura H, Di Lazzaro V, Tokimura Y, Oliviero A, Profice P, Insola A, Mazzone P, Tonali P, Rothwell JC.

J Physiol. 2000 Mar 1;523 Pt 2:503-13

Abstract: EMG responses evoked in hand muscles by transcranial stimulation over the motor cortex were conditioned by a single motor threshold electrical stimulus to the median nerve at the wrist in a total of ten healthy subjects and in five patients who had electrodes implanted chronically into the cervical epidural space. 2. The median nerve stimulus suppressed responses evoked by transcranial magnetic stimulation (TMS) in relaxed or active muscle. The minimum interval between the stimuli at which this occurred was 19 ms. A similar effect was seen if electrical stimulation was applied to the digital nerves of the first two fingers. 3. Median or digital nerve stimulation could suppress the responses evoked in active muscle by transcranial electrical stimulation over the motor cortex, but the effect was much less than with magnetic stimulation. 4. During contraction without TMS, both types of conditioning stimuli evoked a cutaneomuscular reflex that began with a short period of inhibition. This started about 5 ms after the inhibition of responses evoked by TMS. 5. Recordings in the patients showed that median nerve stimulation reduced the size and number of descending corticospinal volleys evoked by magnetic stimulation. 6. We conclude that mixed or cutaneous input from the hand can suppress the excitability of the motor cortex at short latency. This suppression may contribute to the initial inhibition of the cutaneomuscular reflex. Reduced spinal excitability in this period could account for the mild inhibition of responses to electrical brain stimulation.

Comment: This study demonstrates also a small part of the potentiality of the AK technique called Therapy Localization or TL. The cutaneomuscular reflexes have been extensively investigated in the scientific literature, and they may be a part of the mechanism for what is found clinically with TL testing.

The role of paraspinal muscle spindles in lumbosacral position sense in individuals with and without low back pain, Brumagne S, Cordo P, Lysens R, Verschueren S, Swinnen S.

Spine. 2000 Apr 15;25(8):989-94.

STUDY DESIGN: A two-group experimental design with repeated measures on one factor was used. OBJECTIVES: To investigate the role of paraspinal muscle spindles in lumbosacral position sense in individuals with and without low back pain. SUMMARY OF BACKGROUND DATA: Proprioceptive deficits have been identified in patients with low back pain. The underlying mechanisms, however, are not well documented. METHODS: Lumbosacral position sense was determined before, during, and after lumbar paraspinal muscle vibration in 23 young patients with low back pain and in 21 control subjects. Position sense was estimated by calculating the mean absolute error, constant error, and variable error between six criterion and reproduction sacral tilt angles. RESULTS: Repositioning accuracy was significantly lower in the patient group than in healthy individuals (absolute error difference between groups = 2.7 degrees, P < 0.0001). Multifidus muscle vibration induced a significant muscle-lengthening illusion that resulted in an undershooting of the target position in healthy individuals (constant error = -3.1 degrees, P < 0.0001). Conversely, the position sense scores of the patient group did not display an increase in negative directional error but a significant improvement in position sense during muscle vibration (P < 0.05). No significant differences in absolute error were found between the first and last trial in the healthy individuals (P >/= 0.05) and in the patient group (P > 0.05). CONCLUSIONS: Patients with low back pain have a less refined position sense than healthy individuals, possibly because of an altered paraspinal muscle spindle afference and central processing of this sensory input. Furthermore, muscle vibration can be an interesting expedient for improving proprioception and enhancing local muscle control.

Comment: The treatment of myofascial gelosis and fascial tension through percussion (as taught by Dr. Robert Fulford and applied in AK by Dr. Goodheart) has relevance to patients with low back pain who suffer from position sense deficits as described in this paper.

Decrease in quadriceps inhibition after sacroiliac joint manipulation in patients with anterior knee pain, Suter, E., McMorland, G., Herzog, W., Bray, R.

J Manipulative Physiol Ther, 1999;22:149-153

(http://www.journals.elsevierhealth.com/periodicals/ymmt/article/PIIS0161475499701284/abstract)

Background: Evidence exists that conservative rehabilitation protocols fail to achieve full recovery of muscle strength and function after joint injuries. The lack of success has been attributed to the high amount of muscle inhibition found in patients with pathologic conditions of the knee joint. Clinical evaluation shows that anterior knee pain is typically associated with sacroiliac joint dysfunction, which may contribute to the muscle inhibition observed in this patient group. Objective: To assess whether sacroiliac joint manipulation alters muscle inhibition and strength of the knee extensor muscles in patients with anterior knee pain. Design and Setting: The effects of sacroiliac joint manipulation were evaluated in patients with anterior knee pain. The manipulation consisted of a high-velocity low-amplitude thrust in the side-lying position aimed at correcting sacroiliac joint dysfunction. Before and after the manipulation, torque, muscle inhibition, and muscle activation for the knee extensor muscles were measured during isometric contractions using a Cybex dynamometer, muscle stimulation, and electromyography, respectively. Participants: Eighteen patients (mean age, 30.5 ± 13.0 years) with either unilateral (n = 14) or bilateral (n = 4) anterior knee pain. Results: Patients showed substantial muscle inhibition in the involved and the contralateral legs as estimated by the interpolated twitch technique. After the manipulation, a decrease in muscle inhibition and increases in knee extensor torques and muscle activation were observed, particularly in the involved leg. In patients with bilateral anterior knee pain, muscle inhibition was decreased in both legs after sacroiliac joint adjustment. Conclusions: Spinal manipulation might offer an interesting alternative treatment for patients with anterior knee pain and muscle inhibition. Because this clinical outcome study was of descriptive nature rather than a controlled design, biases might have occurred. Thus the results have to be verified in a randomized, controlled, double-blinded trial before firm conclusions can be drawn or recommendations can be made.

Cervical root compression monitoring by flexor carpi radialis H-reflex in healthy subjects, Sabbahi M, Abdulwahab S.

Spine, 1999 Jan 15;24(2):137-41.

STUDY DESIGN: One-group, pretest-postest experimental research with repeated measures. OBJECTIVE: To determine the effect of head postural modification on the flexor carpi radialis H-reflex in healthy subjects. SUMMARY OF BACKGROUND DATA: H-reflex testing has been reported to be useful in evaluating and treating patients with lumbosacral and cervical radiculopathy. The idea behind this technique is that postural modification can cause further H-reflex inhibition, indicating more compression of the impinged nerve root, or recovery, indicating decompression of the root. Such assumptions cannot be supported unless the influence of normal head postural modification on the H-reflex in healthy subjects is studied. METHODS: Twenty-two healthy subjects participated in this study (14 men, 8 women; mean age, 39 +/- 9 years). The median nerve of the subjects at the cubital fossa was electrically stimulated (0.5 msec; 0.2 pulses per second [pps] at H-max), whereas the flexor carpi radialis muscle H-reflex was recorded by electromyography. The H-reflexes were recorded after the subject randomly maintained the end range of head-forward flexion, backward extension, rotation to the right and the left, lateral bending to the right and the left, retraction and protraction. These were compared with the H-reflex recorded during comfortable neutral positions. Data were recorded after the subject maintained the position for 30 seconds, to avoid the effect of dynamic postural modification on the H-reflex. Four traces were recorded in each position. During recording, the H-reflex was monitored by the M-response to avoid any changes in the stimulation-recording condition. RESULTS: Repeated multivariate analysis of variance was used to evaluate the significance of the difference among the H-reflex, amplitude, and latency, in various head positions. The H-reflex amplitude showed statistically significant changes (P < 0.001) with head postural modification. All head positions, except flexion, facilitated the H-reflex. Extension, lateral bending, and rotation toward the side of the recording produced higher reflex facilitation than the other positions. These results indicate that H-reflex changes may be caused by spinal root compression-decompression mechanisms. It may also indicate that relative spinal root decompression occurs in most head-neck postures except forward flexion. CONCLUSIONS: Head postural modification significantly influences the H-reflex amplitude but not the latency. This indicates that the H-reflex is a more sensitive predictor of normal physiologic changes than are latencies. The H-reflex modulation in various head positions may be-caused by relative spinal root compression-decompression mechanisms.

Comment: In AK, the cervical compaction test was developed to monitor this kind of phenomenon. With compression upon the top of the skull, MMT will reveal weaknesses when cervical spine subluxations, and especially cervical disc syndromes are present. This study measures this dynamic.

Electromyographic responses of back and limb muscles associated with spinal manipulative therapy, Herzog, W., Scheele, D., Conway, P.J.

Spine, 1999;24:146-152

(http://www.spinejournal.com/pt/re/spine/abstract.00007632-199901150-00012.htm)

Study Design: Ten young, asymptomatic male subjects underwent 11 clinically relevant spinal manipulative treatments along the length of the spine to test the magnitude and extent of reflex responses associated with the treatments. Objectives: To determine the magnitude and extent of reflex responses elicited by spinal manipulative treatments.

Summary of Background Data: Spinal manipulative treatments have been associated with a reflexogenic relief of pain and a loss of hypertonicity in muscles within the treatment area. However, there is no study in which results show the probability of occurrence or the extent of reflex responses during spinal manipulative treatments. Methods: Asymptomatic subjects received spinal manipulative treatments on the cervical, thoracic, and lumbar levels and on the sacroiliac joint. Reflex activities were measured using 16 pairs of bipolar surface electrodes placed on the back and proximal limb musculature. The percentage of occurrence and the extent of reflex responses in the back and proximal limb musculature were determined. Results: Each treatment produced consistent reflex responses in a target-specific area. The reflex responses occurred within 50-200 msec after the onset of the treatment thrust and lasted for approximately 100-400 msec. The responses were probably of multireceptor origin and were elicited asynchronously. Conclusions: This is the first study in which results show a consistent reflex response associated with spinal manipulative treatments. Because reflex pathways are evoked systematically during spinal manipulative treatment, there is a distinct possibility that these responses may cause some of the clinically observed beneficial effects, such as a reduction in pain and a decrease in hypertonicity of muscles.

Further clinical clarification of the muscle dysfunction in cervical headache, Jull G, Barrett C, Magee R, Ho P.

Cephalalgia, 1999 Apr;19(3):179-85.

Abstract: The Headache Classification Committee of the International Headache Society listed impairments in cervical muscle function as criteria for headaches of cervical spine origin. Fifteen subjects with cervical headache and 15 controls were tested for the frequency of abnormal responses to passive stretching and abnormal muscle contraction. A new test of cranio-cervical flexion was used to assess the contraction of the deep neck flexors. Results indicated a trend towards a higher frequency of abnormal response to passive stretching of the muscles examined in the cervical headache group but only the upper trapezius proved significantly different to the control group. Deep neck flexor muscle contraction was significantly inferior in the cervical headache group. From the perspective of physical characterization of cervical headache, it appears that response from passive stretch of muscle may not be a strong criterion for cervical headache but deep neck flexor performance may have potential to identify musculoskeletal involvement in headache. The finding may also provide positive directions for conservative treatment of cervical headache.

Comment: This is a very important paper for AK. In terms of the etiology of headache, The Headache Classification Committee of the International Headache Society suggests in this study that the performance of the deep neck flexors has greater diagnostic value for musculoskeletal involvement in headache than any other finding.

Orthostatic intolerance and chronic fatigue syndrome associated with Ehlers-Danlos syndrome, Rowe PC, Barron DF, Calkins H, Maumenee IH, Tong PY, Geraghty MT

J Pediatr, 1999 Oct;135(4):494-9.

OBJECTIVE: To report chronic fatigue syndrome (CFS) associated with both Ehlers-Danlos syndrome (EDS) and orthostatic intolerance. STUDY DESIGN: Case series of adolescents referred to a tertiary clinic for the evaluation of CFS. All subjects had 2-dimensional echocardiography, tests of orthostatic tolerance, and examinations by both a geneticist and an ophthalmologist. RESULTS: Twelve patients (11 female), median age 15.5 years, met diagnostic criteria for CFS and EDS, and all had either postural tachycardia or neurally mediated hypotension in response to orthostatic stress. Six had classical-type EDS and 6 had hypermobile-type EDS. CONCLUSIONS: Among patients with CFS and orthostatic intolerance, a subset also has EDS. We propose that the occurrence of these syndromes together can be attributed to the abnormal connective tissue in dependent blood vessels of those with EDS, which permits veins to distend excessively in response to ordinary hydrostatic pressures. This in turn leads to increased venous pooling and its hemodynamic and symptomatic consequences. These observations suggest that a careful search for hypermobility and connective tissue abnormalities should be part of the evaluation of patients with CFS and orthostatic intolerance syndromes.

Comment: The biomedical literature on orthostatic hypotension (a positive Ragland’s sign) is very extensive, and has been a part of standard AK evaluation of patients since 1965 when Dr. Goodheart first pointed out the significance of Adrenal Stress Disorder among chiropractic patients. Most chronic health disorders involving any of the three aspects of the triad of health (structural, chemical, mental) will demonstrate some involvement of the adrenal glands, and complete recovery from a chronic health disorder may require treatment of the adrenal stress disorder that may be present.

Manual Muscle Testing combined with Specific Head Positioning, and other Articular Challenges, as an Assessment of Vertebral Subluxation of the Upper Cervical Spine: A Descriptive Paper,
Dobson GJ.

J Vertebral Subluxation Res,1999;3(2):1-7.

Abstract: This article presents the Dobson Muscle Testing (DMT) procedure. Those aspects of the procedure as it relates to other indicators of vertebral subluxation and other methodologies are described.The procedure detects abberant cervical joint dynamics (movement) through muscle challenges used in combination with various head positions, designed to functionally engage specific articular levels, (positioning) and other articular challenges. In the cervical spine joints and soft tissue there are a large number of mechanoreceptors. Thus, it is postulated that in the presence of vertebral subluxation, when abberant joint mechanics affect these mechanoreceptors, the application of the head postioning challenges produces a barrage of noxious or inappropriate impulses through the cerebellovestibular regulatory circuits. This is believed to result in poor quality motor responses, which may be detected with the DMT procedure through manual muscle testing.The DMT procedure is described as a complement to other forms of vertebral subluxation assessment.To date, clinical observations suggest a positive correlation to Blair upper cervical radiographic analysis in addition to other indicators including muscle and motion palpation and leg length analysis. Further study is planned to test the validity of these observations through controlled studies.

Sacroiliac joint involvement in activation of the porcine spinal and gluteal musculature,Indahl, A., Kaigle, A., Reikeras, O., Holm, S.H.

J Spinal Disord, 1999;12:325-30

Abstract: This experiment involved stimulation of the sacroiliac joint that was found to cause neuromuscular responses in the gluteus maximus, quadratus lumborum, and multifidus muscles. This muscular activation was found to assist in the control of locomotion and body posture and to provide stability to the sacroiliac joint and lumbar spine. Thus, sensitization of sacroiliac joint nociceptive afferents were suggested to not only contribute to mechanical low back pain, but plays a role also in sacroiliac joint biomechanics via reflexogenic activation of the trunk and gluteal muscles.

Comment: Given the results of this study, a larger double-blind study evaluating sacroiliac joint biomechanics in relationship applied kinesiology diagnostic procedures for the sacroiliac joint could be done, wherein back muscles strength tests are measured before and after a course of chiropractic care for the sacroiliac joints.

Shoulder muscle co-ordination during chronic and acute experimental neck-shoulder pain. An occupational pain study,
Madeleine P, Lundager B, Voigt M, Arendt-Nielsen L.

Eur J Appl Physiol Occup Physiol. 1999 Jan;79(2):127-40.

Abstract: Little is known about the mechanisms leading to chronic neck-shoulder musculoskeletal disorders (MSD). The aim of the present study was to investigate and compare motor function during controlled, low load, repetitive work together with chronic or acute experimental neck-shoulder pain. The clinical study was performed on workers with (n = 12) and without (n = 6) chronic neck-shoulder pain. In the experimental study, experimental muscle pain was induced in healthy subjects by intra-muscular injection of hypertonic saline into the trapezius muscle (n = 10). The assessed parameters related to motor performance were: work task event duration, cutting forces, surface electromyogram (EMG) activity in four shoulder muscles, displacement of the center of pressure, and arm and trunk 3D movements. For controlled cutting force levels, chronic and acute experimental pain provoked a series of changes: a decreased working rhythm and a protective reorganization of muscle synergy (experimental study), higher EMG frequency contents which may indicate altered motor unit recruitment, and greater postural activity and a tendency towards increased arm and trunk movements. These pain-related changes can play a role in the development of MSD. The present clinical and experimental study demonstrated similar interactions between motor co-ordination and neck-shoulder pain in occupational settings. We therefore suggest that this experimental model can be used to study mechanisms related to MSD. Information on such modulatory processes may help in the design of new strategies aimed at reducing the development of MSD.

Thoracic position effect on shoulder range of motion, strength, and three-dimensional scapular kinematics, Kebaetse M, McClure P, Pratt NA.

Arch Phys Med Rehabil. 1999 Aug;80(8):945-50

OBJECTIVES: To determine the effect of thoracic posture on scapular movement patterns, active range of motion (ROM) in scapular plane abduction, and isometric scapular plane abduction muscle force. STUDY DESIGN AND METHOD: Repeated measures design. There were 34 healthy subjects (mean age, 30.2 yrs). Each subject was positioned and stabilized while sitting in both erect and slouched trunk postures. In each sitting posture a three-dimensional electromechanical digitizer was used to measure thoracic flexion and scapular position and orientation in three planes. Measurements were taken with the arm (1) at the side, (2) abducted to horizontal in the scapular plane, and (3) at maximum scapular plane abduction. In each posture, isometric abduction muscle force was measured with the arm at the side and abducted to horizontal in the scapular plane. RESULTS: In the slouched posture, the scapula was significantly more elevated in the interval between 0 to 90 degrees abduction. In the interval between 90 degrees and maximum abduction, the slouched posture resulted in significantly less scapular posterior tilting. There was significantly less active shoulder abduction ROM in the slouched posture (mean difference = 23.6 degrees +/- 10.7 degrees). Muscle force was not different between slouched and erect postures with the arm at the side, but with the arm horizontal muscle force was decreased 16.2% in the slouched position. CONCLUSION: Thoracic spine position significantly affects scapular kinematics during scapular plane abduction, and the slouched posture is associated with decreased muscle force.

Hand-grip strength predicts incident disability in non-disabled older men, Giampaoli S, Ferrucci L, Cecchi F, Lo Noce C, Poce A, Dima F, Santaquilani A, Vescio MF, Menotti A.

Age Ageing. 1999 May;28(3):283-8.

OBJECTIVES: To verify if hand-grip performance in older men is a predictor of disability. DESIGN: Population-based prospective study. SETTING: A sample from the Italian rural cohorts of the FINE study (Finland, Italy, Netherlands Elderly), representative of the general population of elderly men surveyed in 1991 and 1995. PARTICIPANTS: 140 men aged 71-91 years who reported no disability in performing activities of daily living (ADLs), instrumental activity of daily living (IADLs) and mobility activities at baseline examination and provided information on their functional status at follow-up 4 years later. MEASUREMENTS: Disability was defined as needing help in performing ADLs, IADLs and mobility. Hand-grip strength was evaluated at baseline by a mechanical dynamometer. RESULTS: After adjusting for potential confounding variables, a lower concentration of high-density lipoprotein cholesterol was the only factor predicting disability in men aged 76 years or younger and only reduced hand-grip strength predicted incident disability in men 77 years or older. CONCLUSION: Poor hand strength as measured by hand-grip is a predictor of disability in older people. The hand-grip test is an easy and inexpensive screening tool to identify elderly people at risk of disability.

Comment: This study demonstrates that muscular strength is a predictor of disability in older people.

EMG recordings of abdominal and back muscles in various standing postures: validation of a biomechanical model on sacroiliac joint stability, Snijders, C.J., Ribbers, M.T., de Bakker, H.V., Stoeckart, R., Stam, H.J.

J Electromyogr Kinesiol, 1998;8:205-14

Abstract: In a biomechanical model we described that for stability of the flat sacroiliac joints (SIJ) muscle forces are required which press the sacrum between the two hip bones (self-bracing). Shear loading of these joints is caused by gravity and longitudinally oriented muscles. Protection against shearing can come from transversely oriented muscles like the internal oblique (OI) abdominal muscles. For validation we used standing postures with significantly more or less OI activity compared to activity in a standardized erect standing reference posture. OI activity decreased significantly when (a) resting on one leg (the contralateral), as can be observed at bus stops, (b) tilting the pelvic backward and (c) applying a pelvic belt. We explain this decrease of OI activity by, respectively, decrease of gravity load, decrease of load from the psoas major muscles, and a substitute of self-bracing. The outcome of this study is in line with the biomechanical model on SIJ stability. Clinical relevance of this study regards aspecific low back pain and is found in the effect of the use of a pelvic belt, of a trunk position as adopted when wearing a small rucksack and of the benefit of exercising trunk muscles in extension and torsion.

The intra-examiner reliability of manual muscle testing of the hip and shoulder with a modified sphygmomanometer: a preliminary study of normal, Perossa DR, Dziak M, Vernon HT, Hayashita K.

J Can Chiropr Assoc, Jun 1998;42:2.

The Anatomical Basis for the Effectiveness of Chiropractic Spinal Manipulation in Treating Headache, Hack G

Cervicocephalic kinesthetic sensibility, active range of cervical motion, and oculomotor function in patients with whiplash injury, Heikkila HV,

Wenngren BI.

Arch Phys Med Rehabil. 1998 Sep;79(9):1089-94

OBJECTIVE: To investigate cervicocephalic kinesthetic sensibility, active range of cervical motion, and oculomotor function in patients with whiplash injury. DESIGN: A 2-year review of consecutive patients admitted to the emergency unit after whiplash injury. SETTING: An otorhinolaryngology department. PATIENTS AND SUBJECTS: Twenty-seven consecutive patients with diagnosed whiplash injury (14 men and 13 women, mean age, 33.8yrs [range, 18 to 66yrs]). The controls were healthy subjects without a history of whiplash injury. MAIN OUTCOME MEASURES: Oculomotor function was tested at 2 months and at 2 years after whiplash injury. The ability to appreciate both movement and head position was studied. Active range of cervical motion was measured. Subjective intensity of neck pain and major medical symptoms were recorded. RESULTS: Active head repositioning was significantly less precise in the whiplash subjects than in the control group. Failures in oculomotor functions were observed in 62% of subjects. Significant correlations occurred between smooth pursuit tests and active cervical range of motion. Correlations also were established between the oculomotor test and the kinesthetic sensibility test. CONCLUSION: The results suggest that restricted cervical movements and changes in the quality of proprioceptive information from the cervical spine region affect voluntary eye movements. A flexion/extension injury to the neck may result in dysfunction of the proprioceptive system. Oculomotor dysfunction after neck trauma might be related to cervical afferent input disturbances.

Comment: Several recent reviews and articles on eye muscle proprioception agree that there is abundant evidence that the brain utilizes information from the eye muscle proprioceptors for balance and postural control. In applied kinesiology chiropractic methodology, a means for testing the integration of the muscles in the body with the visual reflexes has been termed ocular lock. It demonstrates the failure of the eyes to work together on a binocular basis through the cardinal fields of gaze.  This is usually not gross pathology of cranial nerves III, IV, and VI; rather it is poor functional organization. Mechanical irritation of cranial nerves III, IV, or VI (usually VI) may be responsible for disturbed binocular function leading to discordant sensory inputs from the visual righting reflex. When the eyes are turned in a specific direction, a previously strong indicator muscle will weaken when the ocular lock test is positive, and there is probably disturbance in the visual righting, vestibulo-ocular, or opto-kinetic reflexes.  The relevance of the eyes to movement disorders, especially after whiplash trauma, is described in this report.

Dialogue between the CNS and the immune system in lymphoid organs, Straub RH, Westermann J, Scholmerich J, Falk W

The effect of upper cervical or sacroiliac manipulation on hip flexion range of motion, Pollard H, Ward G.

J Manipulative Physiol Ther. 1998 Nov-Dec;21(9):611-6.

OBJECTIVES: To compare the effectiveness of an upper cervical manipulation and a manipulation of the sacroiliac joint for increasing hip range of motion. DESIGN: Clinical cohort study. SETTING: Macquarie University Centre for Chiropractic Outpatient Clinic. SAMPLE: Fifty-two randomly chosen university students aged 18 to 34 yr. METHOD: A reliable hand-held dynamometer was used to determine the end point of range of motion before and after the application of a treatment. Three groups of subjects were created: cervical manipulation, sacroiliac manipulation and sham/placebo. Range of motion of the hip in flexion (SLR) was used as the independent variable. RESULTS: The two manipulative treatments resulted in increased flexion range of motion at the hip. Statistical analysis revealed that only the upper cervical manipulation procedure increased hip flexion range of motion significantly. CONCLUSION: The results suggest that manual therapy of the neck may affect hip range of motion in normal adults. Findings such as these may indicate the existence of a link between the cervical spine and the lower extremity.

Comment: In fact, AK research and experience has shown this relationship since its beginning. Upper cervical subluxations and fixations have been specifically correlated with weakness of the iliopsoas and gluteus maximus muscles. And muscle weakness is frequently the cause of a decreased ROM on testing the extremities, low back and neck.

High cervical stress and apnoea, Koch LE, Biedermann H, Saternus KS.

Forensic Sci Int. 1998 Oct 12;97(1):1-9.

Abstract: The aim of this study was to investigate vegetative reactions in infants after mechanical irritation of the suboccipital region. The investigation is based on 199 infants who were observed while being treated with a suboccipital impulse (manual therapy). The results revealed vegetative reactions in more than half of all cases (52.8%, n = 105). The frequency of such vegetative reactions observed was at follows: flush 48.7% (n = 97), apnoea 22.1% (n = 44), hyperextension 13% (n = 26), and sweating 7.5% (n = 15). It is pointed out that approximately 25% of all the infants examined reacted by apnoea due to a mechanical irritation of the suboccipital region. This symptom was part of an extensive vegetative reaction. This method of inducing an apnoea has not yet been described; from this it follows that there are close relations to sudden infant death.

Rearfoot-forefoot orientation and traumatic risk for runners, Busseuil C, Freychat P, Guedj EB, Lacour JR.

Foot Ankle Int. 1998 Jan;19(1):32-7.

Abstract: Factors making runners more susceptible to injuries were identified with a comparative study between a healthy control group (216) and runners (66) suffering from overuse pathology. On static and dynamic footprint, the angles alpha0 (static) and alpha1 (dynamic) between heel and forefoot have been measured. Analysis showed that the injured subjects have a more pronated foot than control group subjects. These results suggest that the pronating foot configuration would be an injury risk factor.

Comment: The importance of proper foot function to the gait cycle has been described previously. Specifically, the researchers looked at runners who needed treatment for iliotibial band syndrome, Achilles tendonitis, stress fracture of the tibia, tibial periostitis and plantar fascitis. The significant correlation between these problems and runners with foot dysfunction shows the importance of thorough investigation of the feet in runners with injuries. The many factors that come into play for normal foot function are purposely incorporated into AK examination of the feet.

The Role of the Chiropractic Adjustment in the Care and Treatment of 332 Children with Otitis Media, Fallon, J.

Journal of Clinical Chiropractic Pediatrics, 1997 Oct; 2(2) :167-83

Objective: To conduct a pilot study of chiropractic adjustive care on children with otitis media using tympanography as an objectifying measure, and to propose possible mechanisms whereby subluxation is implicated in the pathophysiology of otitis media. Design: Case series Setting: Subjects presented in a private clinical practice in New Rochelle, New York. The subjects were referred by various sources including pediatricians, other MDs, chiropractors and parents. Participants: 332 children who presented consecutively with previously diagnosed otitis media, ages 27 days to 5 years. Main Outcome Measures: A survey of the parent/guardian was used to determine historical data with respect to previous otitis media bouts, age of onset of initial otitis media, feeding history, history of antimicrobial therapy, referral patterns, and birth history. Otoscopic and tympanographic data was collected as well as data concerning the number of adjustments administered to produce resolution of the otitis media. Data with respect to recurrence rates over six months was also collected. Results: The average number of adjustments administered by types of otitis media were as follows: acute otitis media (n=127) 4.0±1.03, chronic/serous otitis media (n=104) 5.1±1.53, for the mixed type of bilateral otitis media (n=10) 5.3±1.35 and where no otitis was initially detected on otoscopic and tympanographic exam (but with history of multiple bouts) (n=74) 5.88±1.87. The number of days it took to normalize the otoscopic examination was for acute 6.67±1.9 chronic/serous 8.57±1.96, and 10.18±3.39, and mixed 10.9±2.02. The overall recurrence rate over a six month period from initial presentation in the office was for acute 11.02%, chronic/serous 16.34%, for mixed 30% and for none present 17.56%. Conclusion: To our knowledge this is the first time that tympanography has been used as an objectifying tool with respect to the efficacy of the chiropractic adjustment in the treatment of children with otitis media. As tympanography has been used extensively in the medical assessment of children with otitis media, it also serves as a bridge from which the chiropractic field and the medical field can begin to communicate with respect to otitis media. The results indicate that there is a strong correlation between the chiropractic adjustment and the resolution of otitis media for the children in this study. Normal cranial molding, which is essential for the proper juxtaposition of the cranial bones, often does not occur in the case of a birth malposition, as well as in the case of the child born with the aid of a C- section. This pilot study can now serve as a starting point from which the chiropractic profession can begin to examine its role in the treatment of children with otitis media. Large-scale clinical trials need to be undertaken in the field using tympanography as an objectifying measure. In addition, the role of the occipital adjustment needs to be examined. This study begins the process of examining the role of the vertebral cranial subluxation complex in the pathogenesis of otitis media, and the efficacy of the chiropractic adjustment in its resolution.

Reduced muscle function in patients with osteoarthritis, Fisher NM, Pendergast DR.

-- Department of Rehabilitation Medicine, State University of New York at Buffalo, USA.

Scand J Rehabil Med.1997 Dec;29(4):213-21

Abstract: The purpose of this study was to determine whether subjects with knee osteoarthritis (OA) had reduced muscle strength at various muscle lengths, endurance, contraction velocity and functional capacity, compared with control subjects and whether the decrease was related to functional capacity. Forty-five men and 45 women with knee OA were compared with a control group (41 males, 63 females) of similar age for functional capacity, maximal isometric strength (in vivo length-tension relationship) and endurance (in vivo force-time relationship) of knee flexion and extension and maximal angular velocity (in vivo force-velocity relationship) of knee extension. The OA subjects had increased difficulty (2.03 +/- 0.53) and pain (1.65 +/- 0.29) for activities of daily living (ADLs) and significantly lower strength for extension (72%) and flexion (56%), endurance for the quadriceps (203%) and hamstrings (214%) and velocity (128%). The reductions were greater at longer muscle lengths. These data demonstrate that patients with knee OA have reduced muscle function and functional capacity compared to controls.

Muscle inhibition following knee injury and disease, Herzog W, Suter E.

Sportverletz Sportschaden, 1997 Sep;11(3):74-8.

Abstract: It has been observed that knee extensor muscles cannot be fully activated during voluntary contractions following knee injuries. This muscle inhibition has an unknown origin and appears to hinder full rehabilitation of the affected joint. We have investigated muscle inhibition during and following knee injuries in non-athletic and athletic patients and compared their results to non-athletic, unaffected volunteer subjects. There appears to be a small amount of muscle inhibition in the knee extensors of normal subjects; this inhibition increases dramatically following knee injury, and appears to go back to normal levels following surgical intervention, aggressive physiotherapy, or a sufficient amount of time. Depending on the intervention, strength deficits of the affected compared to the unaffected knee extensor muscles may persist. Aggressive physiotherapy can eliminate strength deficits following knee injury through an increased ability to recruit the knee extensors in patients more completely compared to normal subjects.

Comment: The correlation between joint injury to the knee and muscle inhibition found upon muscle testing is very clearly described here. This is a central tenet of AK, i.e. that joint injuries will produce muscle weakness that can be specifically diagnosed and treated. On a clinical basis, AK physicians find this consistently when testing patients with knee injuries. Manual therapy is shown in this paper to improve the strength of muscles supporting the knee, and led to an improvement in function and a decrease in pain for these patients.

Athletic performance and physiological measures in baseball players following upper cervical chiropractic care: a pilot study, Schwartzbauer J, Kolber J, et al.

J Vertebral Subluxation Res, 1997;1(4):33-39.

Abstract: This study analyzed the athletic performance in baseball players following upper cervical chiropractic care. Twenty-one male university baseball players free from physical injury completed the study, nine in the chiropractic group and twelve in the control group. The control group did not receive chiropractic care. The subluxations were determined from radiographic analysis and the Palmer toggle-recoil adjustment in side posture with a drop head piece was employed. The results showed significant improvement (p < 0.05) at fourteen weeks of care in muscle strength (repetitive shoulder abduction), long jump distance, and capillary counts in the group receiving adjustments.

Stabilizing function of trunk flexor-extensor muscles around a neutral spine posture, Cholewicki J, Panjabi MM, Khachatryan A

Spine, 1997 Oct 1;22(19):2207-12.

STUDY DESIGN: This study examined the coactivation of trunk flexor and extensor muscles in healthy individuals. The experimental electromyographic data and the theoretical calculations were analyzed in the context of mechanical stability of the lumbar spine. OBJECTIVES: To test a set of hypotheses pertaining to healthy individuals: 1) that the trunk flexor-extensor muscle coactivation is present around a neutral spine posture, 2) that the coactivation is increased when the subject carries a load; and 3) that the coactivation provides the needed mechanical stability to the lumbar spine. SUMMARY OF BACKGROUND DATA: Theoretically, antagonistic trunk muscle coactivation is necessary to provide mechanical stability to the human lumbar spine around its neutral posture. No experimental evidence exists, however, to support this hypothesis. METHODS: Ten individuals executed slow trunk flexion-extension tasks, while six muscles on the right side were monitored with surface electromyography: external oblique, internal oblique, rectus abdominus, multifidus, lumbar erector spinae, and thoracic erector spinae. Simple, but realistic, calculations of spine stability also were performed and compared with experimental results. RESULTS: Average antagonistic flexor-extensor muscle coactivation levels around the neutral spine posture as detected with electromyography were 1.7 +/- 0.8% of maximum voluntary contraction for no external load trials and 2.9 +/- 1.4% of maximum voluntary contraction for the trials with added 32-kg mass to the torso. The inverted pendulum model based on static moment equilibrium criteria predicted no antagonistic coactivation. The same model based on the mechanical stability criteria predicted 1.0% of maximum voluntary contraction coactivation of flexors and extensors with zero load and 3.1% of maximum voluntary contraction with a 32-kg mass. The stability model also was run with zero passive spine stiffness to simulate an injury. Under such conditions, the model predicted 3.4% and 5.5% of maximum voluntary contraction of antagonistic muscle coactivation for no extra load and the added 32 kg, respectively. CONCLUSIONS: This study demonstrated that antagonistic trunk flexor-extensor muscle coactivation was present around the neutral spine posture in healthy individuals. This coactivation increased with added mass to the torso. Using a biomechanical model, the coactivation was explained entirely on the basis of the need for the neuromuscular system to provide the mechanical stability to the lumbar spine.

Comment: AK demonstrates that muscle imbalance is most often primary to structural and postural deviations, from vertebral subluxations to obvious postural imbalances. Early in AK it was recognized that the short or hypertonic muscle is frequently secondary to poor function of its antagonist muscle. On MMT the antagonist muscle tests weak, indicating that the coactivation necessary for pain free function and, as in this study, neutral spine posture.

Muscle function and gait in patients with knee osteoarthritis before and after muscle rehabilitation, Fisher NM, White SC, Smolinski RJ, Pendergast DR.

Disabil and Rehabil.1997 Feb;19(2):47-55

Abstract: Patients with knee osteoarthritis (OA) have reduced functional capacity and muscle function that improves significantly after quantitative progressive exercise rehabilitation (QPER). The effects of these changes on the biomechanics of walking have not been quantified. Our goal was to quantify the effects of knee OA on gait before and after QPER. Bilateral kinematic and kinetic analyses were performed using a standard link-segment analysis on seven women (60.9 +/- 9.4 years) with knee OA. All functional capacity, muscle function and gait variables were initially reduced compared to age-matched controls. Muscle strength, endurance and contraction speed were significantly improved (55%, 42% and 34%, respectively) after 2 months of QPER (p < 0.05), as were function (13%), walking time (21%), difficulty (33%) and pain (13%). There were no significant changes in the gait variables after QPER. To use the QPER improvements to the best advantage, gait retraining may be necessary to "re-programme' the locomotor pattern.

Spinal manipulation results in immediate H-reflex changes in patients with unilateral disc herniations, Floman Y, Liram N, Gilai AN.

Eur Spine J. 1997;6(6):398-401.

Abstract: The aim of this clinical investigation was to determine whether the abnormal H-reflex complex present in patients with S1 nerve root compression due to lumbosacral disc herniation is improved by single-session lumbar manipulation. Twenty-four patients with unilateral disc herniation at the L5-S1 level underwent spinal H-reflex electro-physiological evaluation. This was carried out before and after single-session lumbar manipulation in the side-lying position. Eligibility criteria for inclusion in the study were: predominant sciatica, no motor or sphincteric involvement, unilateral disc herniation at the L5-S1 level on CT or MR imaging, age between 20 and 50 years. H-reflex responses were recorded bilaterally from the gastrosoleus muscle following stimulation of tibial sensory fibers in the popliteal fossa. H-reflex amplitude in millivolts (HR-A) and H-reflex latency in milliseconds (HR-L) were measured from the spinal reflex response. Pre- and post-manipulation measurements were compared between the affected side and the healthy side. Statistical evaluation was performed by the Wilcoxon matched-pairs test (SPSS). Thirteen patients displayed abnormal H-reflex parameters prior to lumbar manipulation, indicating an S1 nerve root lesion. The mean amplitude was found to be significantly lower on the side of disc herniation than on the normal, healthy side (P = 0.0037). Following manipulation, the abnormal HR-A increased significantly on the affected side while the normal HR-A on the healthy side remained unchanged (P = 0.0045). There was a significant difference between latencies on the affected side and those on the healthy side (P = 0.003). Following manipulation there was a trend toward decreased HR-L. However, this trend did not reach statistical significance (P = 0.3877). Eight patients displayed no H-reflex abnormalities before or after manipulation. Their respective HR-A and HR-L values did not change significantly following manipulation. Three additional patients were excluded due to technical difficulties in achieving manipulation or measuring spinal reflex. These observations may lend physiological support for the clinical effects of manipulative therapy in patients with degenerative disc disease.

Chronic neck pain, standing balance, and suboccipital muscle atrophy--a pilot study, McPartland JM, Brodeur RR, Hallgren RC.

J Manipulative Physiol Ther. 1997 Jan;20(1):24-9.

OBJECTIVE: To study the relationship between chronic neck pain, standing balance and suboccipital muscle atrophy. We hypothesize that patients with chronic neck pain have more somatic dysfunction in the cervical spine than control subjects without neck pain. We also hypothesize that patients with chronic neck pain and somatic dysfunction exhibit more atrophy of suboccipital muscles. Lastly, because suboccipital muscles have a high density of proprioceptors, we hypothesize that chronic pain patients exhibit a loss in standing balance. DESIGN: Randomized, controlled, partially blind study examining chronic neck pain patients and control subjects for differences in degree of upper cervical somatic dysfunction, standing balance and suboccipital muscle atrophy. SETTING: Subjects were recruited from a clinical practice at Michigan State University; controls were recruited from the faculty, staff and students. PARTICIPANTS: Seven chronic neck pain patients and seven asymptomatic control subjects. MAIN OUTCOME MEASURES: Palpation was used to diagnose somatic dysfunction in the upper cervical spine. Balance parameters were calculated using a force platform; muscle atrophy was judged with magnetic resonance images. RESULTS: Chronic neck pain patients had almost twice as many somatic dysfunctions as controls (p = .028). Force platform results showed a decrease in standing balance in patients compared with control subjects (p = .004). MRI showed that chronic neck pain subjects had marked atrophy of the rectus capitis posterior major and minor muscles, including fatty infiltration. CONCLUSIONS: This study suggests that there is a relationship between chronic pain, somatic dysfunction, muscle atrophy and standing balance. We hypothesize a cycle initiated by chronic somatic dysfunction, which may result in muscle atrophy, which can be further expected to reduce proprioceptive output from atrophied muscles. The lack of proprioceptive inhibition of nociceptors at the dorsal horn of the spinal cord would result in chronic pain and a loss of standing balance.

Upper trapezius muscle activity during the brachial plexus tension test in asymptomatic subjects,
Balster SM, Jull GA.

Man Ther. 1997 Aug;2(3):144-149.

Abstract: The brachial plexus tension test (BPTT) is used clinically to test the dynamics of the neural tissues of the upper quadrant. The upper trapezius muscle and the nerves of the brachial plexus share common anatomical locations and are jointly affected by BPTT movements. This study investigated the relationship between the BPTT, upper trapezius muscle activity and range of neural tissue extensibility in asymptomatic subjects. Normal male subjects with greater and lesser neural tissue extensibility were tested. Results revealed that those with lesser neural extensibility exhibited significantly greater upper trapezius muscle activity during discrete BPTT stages. There was no difference between groups in the levels of pain perceived with the test. These results suggest that asymptomatic neural tissues are protected from stretch by muscle activity not solely mediated by pain but also possibly mediated by stretch receptors in neural structures.

Comment: The diagnosis and treatment of injuries to neuromuscular spindle cells, located throughout the muscle, is a high priority in AK therapy.

Excitability changes in human sensory and motor axons during hyperventilation and ischaemia,
Mogyoros I, Kiernan MC, Burke D, Bostock H.

Brain. 1997 Feb;120 ( Pt 2):317-25.

Abstract: This study was undertaken to compare the excitability changes of sensory and motor axons during hyperventilation and ischaemia, and to determine why ectopic impulse activity develops more readily during hyperventilation, and in sensory fibres. During hyperventilation for 20 min, all six subjects reported paraesthesiae in the hand and face, and four out of the six developed muscle twitching and cramps, associated with significant decreases of 20-30% in the threshold current required to produce sensory and motor potentials of constant size. During ischaemia four out of the six subjects reported paraesthesiae, but none reported muscle twitching. There were significant decreases of 15-20% in threshold for sensory and motor fibres. Ischaemia produced a marked decrease in supernormality, an increase in refractoriness and an increase in latency of the test compound sensory or motor potential, changes that were not seen with hyperventilation. The decrease in threshold during these manoeuvres was associated with a significant increase in strength--duration time constant (tau SD), indicating a relatively greater decrease in rheobase current. Using the technique of latent addition, we found that the changes in tau SD were consistent with a recently proposed model in which non-inactivating, voltage-dependent 'threshold channels' (presumably persistent Na+ channels) are active at resting potential. The failure of hyperventilation to alter conduction velocity, refractoriness or supernormality appreciably indicates that, unlike ischaemic depolarization, hyperventilation does not increase inactivation of conventional Na+ channels or activation of K+ channels, and this implies that the hyperventilation-induced increase in excitability is not the result of conventional depolarization, as seems to occur during ischaemia. These results suggest that hyperventilation has a rather selective action on the threshold channels, and they help to explain its greater effectiveness compared with ischaemia in provoking ectopic discharges. The greater expression of threshold channels in sensory than in motor fibres can explain why hyperventilation induces paraesthesiae before fasciculation and why only paraesthesiae occur during ischaemia.

A tension-based theory of morphogenesis and compact wiring in the central nervous system, Van Essen DC.

Nature. 1997 Jan 23;385(6614):313-8.

Abstract: Many structural features of the mammalian central nervous system can be explained by a morphogenetic mechanism that involves mechanical tension along axons, dendrites and glial processes. In the cerebral cortex, for example, tension along axons in the white matter can explain how and why the cortex folds in a characteristic species-specific pattern. In the cerebellum, tension along parallel fibres can explain why the cortex is highly elongated but folded like an accordion. By keeping the aggregate length of axonal and dendritic wiring low, tension should contribute to the compactness of neural circuitry throughout the adult brain.

Chiropractic Treatment of the Musculoskeletal System During Pregnancy, Bilgrai-Cohen K.

Journal Of The American Chiropractic Association May 1997: 33-34, 90.

Abstract: The childbearing year is a period of dynamic change and adaptation. Alterations occur in every system, including the musculoskeletal system. This article will discuss the major structural changes inherent in pregnancy, the goals of therapy and protocol for the major presenting complaints, including sacroiliac, lumbar and thoracic involvement Pregnancy is a time of profound change and adaptation. As early as 10-12 weeks after fertilization, increased estrogen and relaxin begin to affect the musculoskeletal system by causing the softening of ligaments and increased joint laxity. Compensation for the enlarging uterus, anteriorly, produces the need for the pregnant woman to lean back, thus increasing the lumbar lordosis shifting the center of gravity over the lower extremity. I point out the three joints in the ring (two SI joints and one pubic symphysis) and explain that hormonally, one or both of the SI joints has become softened and is less supportive than normal. The tender muscles and joint pain is the body’s response to this instability in the joints. A portion of my treatment of sacroiliac dysfunction occurs with the patient in the prone position. I accomplish this by using SOT-type blocks and pillows. Sacroiliac Involvement In the non-gravid state, the sacroiliac (SI) joint is very stable relative to the lumbosacral joint. However, during pregnancy, the ligamentous support to the SI joint is significantly relaxed. This is the most common presenting musculoskeletal complaint comprising 75-85 percent of women seen during pregnancy. A portion of my treatment of sacroiliac dysfunction occurs with the patient in the prone position. I accomplish this by using SOT-type blocks and pillows. Lumbopelvic treatment considerations focus on the pelvic block placement with the patient in the prone position, sacral pumping into dural flexion on inhalation, adjust for bilateral AS ilium, and neurolymphatic drainage particularly over the sacrum. Thoracic techniques are also stressed in many ways during pregnancy due to enlargement and increased weight in the breasts, widening of the sub-costal angle and pressure on the lower four to five ribs, viscero-somatic reflex from stressed organs such as the stomach, liver and pancreas and response to increasing lordosis of the lumbar region.

Altered patterns of abdominal muscle activation in patients with chronic low back pain, O'Sullivan P, Twomey L, Allison G, Sinclair J, Miller K.

Aust J Physiother. 1997;43(2):91-98.

Interaction between the porcine lumbar intervertebral disc, zygapophysial joints, and paraspinal muscles, Indahl A, Kaigle AM, Reikeras O, Holm SH.

Spine. 1997 Dec 15;22(24):2834-40.

STUDY DESIGN: A porcine model was used to study whether muscular activation in the paraspinal muscles caused by nerve stimulation in the anulus fibrosus of a lumbar intervertebral disc could be altered by saline injection into the zygapophysial (facet) joint. OBJECTIVES: To elucidate possible mechanisms regarding the nerve pathways and interactions between the intervertebral disc, zygapophysial joints, and the paraspinal musculature. SUMMARY OF BACKGROUND DATA: The physiologic basis for chronic low back pain, including muscular spasm, is uncertain. Although extensive research involving the lumbar motion segments and the surrounding tissues has been performed, the neuromuscular connection has not been sufficiently investigated. MATERIALS AND METHODS: Twenty-three adolescent pigs were used to measure the electromyographic response in the paraspinal musculature to electrical stimulation of the posterolateral L3-L4 anulus fibrosus, before and after introduction of physiologic saline into the zygapophysial joint. Motor unit action potentials were recorded using three sets of needle electrodes placed into the deepest fascicles of the multifidus, bilateral to the L4 and L5 spinous processes, and into the central longissimus musculature, bilateral to the L4 spinous process. RESULTS: Stimulation of the nerves within the posterolateral anulus of the disc elicited reactions in the paraspinal muscles, namely the lumbar multifidus and longissimus. Introduction of physiologic saline into the zygapophysial joint resulted in a reduction in the motor unit action potential amplitude. This reduction was manifested as an immediate and constant reduction, a graded reduction, or a delayed reaction, during which the reduction occurred an average of 5 minutes after the saline injection. CONCLUSIONS: Introduction of physiologic saline into the zygapophysial joint reduced the stimulation pathway from the intervertebral disc to the paraspinal musculature. The zygapophysial joints may therefore have a regulating function, controlling the intricate neuromuscular balance in the lumbar motion segment.

Comment: This study shows that muscle strength changes specifically after stimulation or irritation of the facet joints of the spine.

Mechanisms of referred visceral pain: uterine inflammation in the adult virgin rat results in neurogenic plasma extravasation in the skin, Wesselmann U,

Lai J.

Pain. 1997 Dec;73(3):309-17

Abstract: The purpose of this study was to investigate the mechanisms of referred pain observed in female patients with pain from the reproductive organs. We developed a model of inflammatory uterine pain in the rat. Inflammation of the uterus in rats pretreated with Evans Blue Dye resulted in dye extravasation in the skin over the abdomen, groin, lower back, thighs, perineal area and proximal tail, thus providing for the first time evidence for the trophic changes observed in the area of referred visceral pain in an animal model of uterine pain. The neuronal pathways mediating the observed dye extravasation in the skin after uterine inflammation may include dichotomizing afferent fibers, afferent-afferent interactions via a spinal cord pathway or a sympathetic reflex. This model will allow us to gain further insight into the mechanisms of referred pain and the trophic changes observed in the area of referred pain in visceral disease.

Comment: A crucial development in AK occurred when Goodheart observed that if a patient touched an area of dysfunction, the results of MMT changed. Therapy localization has numerous applications in AK including TL to various reflexes, subluxations, meridian points, nerve receptors and other areas. This paper explains part of this fascinating development in the healing arts that has been proven helpful in the diagnosis of physical dysfunctions in patients.

Postural stability, neck proprioception and tension neck, Koskimies K, Sutinen P, Aalto H, Starck J, Toppila E, Hirvonen T, Kaksonen R, Ishizaki H, Alaranta H, Pyykko I.

Acta Otolaryngol Suppl. 1997;529:95-7.

Abstract: We examined whether tension neck (TN) may due to inadequate proprioceptive and vestibular activation of the cervico-collic reflex (CCR). CCR and vestibulospinal responses (VSRs) were recorded from 106 forest workers by stimulating the neck, lumbar or calf proprioceptors by vibration. The VSRs were recorded with posturography. TN occurred in 27 out of 106 subjects. The subjects with TN (48.5 years) were older than those without TN (43.1). The mean body sway during quiet stance was the same in both groups during the neck stimulation. In subjects with tension neck stimulation of neck or lumbar proprioceptors caused excessive, unpredictable body excursion in the lateral and anteroposterior direction that continued after stimulation. Results from stimulation of lower limb proprioceptors did not significantly differ between the 2 groups. In logistic regression analysis a model to predict TN consisting of perstimulatory postural stability (odds ratio 1.4) and poststimulatory postural stability (odds ratio 1.8) turned out to be statistically significant. The anatomical findings of CCR in the medulla oblongata suggest that neck muscle afferents control the posture and muscle activity of the neck. The erroneus facilitation of proprioception in TN subjects indicate that TN may be raised by inadequate facilitation of CCR.

The manual muscle examination for rotator cuff strength. An electromyographic investigation, Kelly BT, Kadrmas WR, Speer KP.

Am J Sports Med. 1996 Sep-Oct;24(5):581-8.

Abstract: The electromyographic activity of eight muscles of the rotator cuff and shoulder girdle (supraspinatus, infraspinatus, subscapularis, pectoralis, latissimus dorsi, and the anterior, middle, and posterior deltoid) was measured from the nondominant shoulders of 11 subjects during a series of 29 isometric contractions. The contractions simulated different positions used for strength testing of the rotator cuff and involved elevation, external rotation, and internal rotation at three degrees of initial humeral rotation (-45 degrees of internal rotation, 0 degree, +45 degrees of external rotation) and scapular elevation (0 degree, 45 degrees, 90 degrees). Isolation of the supraspinatus muscle was best achieved with the test position of elevation at 90 degrees of scapular elevation and +45 degrees (external rotation) of humeral rotation. Isolation of the infraspinatus muscle was best achieved with external rotation at 0 degree of scapular elevation and -45 degrees (internal rotation) of humeral rotation. Isolation of the subscapularis muscle was best achieved with the Gerber push-off test. This study used four criteria for identifying the optimal manual muscle test for each rotator cuff muscle: 1) maximal activation of the cuff muscle, 2) minimal contribution from involved shoulder synergists, 3) minimal provocation of pain, and 4) good test-retest reliability. Based on the results of this study and known painful arcs of motion, an objective identification of the optimal tests for the manual muscle testing of the cuff was elucidated.

Normative values for isometric muscle force measurements obtained with hand-held dynamometers, Andrews AW, Thomas MW, Bohannon RW.

-- University of North Carolina Hospitals, Chapel Hill, 27514, USA.

Phys Ther. 1996 Mar;76(3):248-59. 

BACKGROUND AND PURPOSE: The extent of a patient's impairment can be established by comparing measurements of that patient's performance with normative values obtained from apparently unimpaired individuals. Only a few studies have described normative values for muscle strength measured by hand-held dynamometry. The purpose of this study of older adults, therefore, was to obtain normative values of maximum voluntary isometric force using hand-held dynamometers. SUBJECTS: One hundred fifty-six asymptomatic adults (77 men, 70 women) participated in this study. The subjects' mean age was 64.4 years (SD=8.3, range=50-79). The male subjects' mean age was 64.5 years (SD=8.4, range=50-79), and the female subjects' mean age was 64.3 years (SD=8.2, range=50-79). METHODS: Gender, age, dominant side, height, weight, and activity level were recorded. Eight upper-extremity movements (shoulder flexion, extension, abduction, and medial and lateral rotation; elbow flexion and extension; and wrist extension) and five lower-extremity movements (hip flexion and abduction, knee flexion and extension, and ankle dorsiflexion) were resisted by one of three experienced testers using a strain-gauge hand-held dynamometer. RESULTS: Gender, age, and weight were identified as independent predictors of force for all muscle actions on both the dominant and nondominant sides. These variables were used, therefore, to create regression equations and normative values for the force of each muscle action. CONCLUSION AND DISCUSSION: The reference values provided may allow clinicians who follow the described testing protocol to estimate the severity of force-generating impairments in patients aged 50 to 79 years.

Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of transversus abdominis, Hodges PW, Richardson CA.

Spine, 1996 Nov 15;21(22):2640-50.

STUDY DESIGN: The contribution of transversus abdominis to spinal stabilization was evaluated indirectly in people with and without low back pain using an experimental model identifying the coordination of trunk muscles in response to a disturbances to the spine produced by arm movement. OBJECTIVES: To evaluate the temporal sequence of trunk muscle activity associated with arm movement, and to determine if dysfunction of this parameter was present in patients with low back pain. SUMMARY OF BACKGROUND DATA: Few studies have evaluated the motor control of trunk muscles or the potential for dysfunction of this system in patients with low back pain. Evaluation of the response of trunk muscles to limb movement provides a suitable model to evaluate this system. Recent evidence indicates that this evaluation should include transversus abdominis. METHODS: While standing, 15 patients with low back pain and 15 matched control subjects performed rapid shoulder flexion, abduction, and extension in response to a visual stimulus. Electromyographic activity of the abdominal muscles, lumbar multifidus, and the surface electrodes. RESULTS: Movement in each direction resulted in contraction of trunk muscles before or shortly after the deltoid in control subjects. The transversus abdominis was invariably the first muscle active and was not influenced by movement direction, supporting the hypothesized role of this muscle in spinal stiffness generation. Contraction of transversus abdominis was significantly delayed in patients with low back pain with all movements. Isolated differences were noted in the other muscles. CONCLUSIONS: The delayed onset of contraction of transversus abdominis indicates a deficit of motor control and is hypothesized to result in inefficient muscular stabilization of the spine.

Comment: This study elegantly demonstrates that sensory and motor function is integrated, and that improper sequencing of muscle groups results in disjointed movement and pain. AK has argued from its founding that postural control is dependent upon the ability of the individual to properly interpret sensory information and execute an appropriate motor response.

Multifidus muscle recovery is not automatic after resolution of acute, first-episode low back pain, Hides JA, Richardson CA, Jull GA.

Spine. 1996 Dec 1;21(23):2763-9.

STUDY DESIGN: A clinical study was conducted on 39 patients with acute, first-episode, unilateral low back pain and unilateral, segmental inhibition of the multifidus muscle. Patients were allocated randomly to a control or treatment group. OBJECTIVES: To document the natural course of lumber multifidus recovery and to evaluate the effectiveness of specific, localized, exercise therapy on muscle recovery. SUMMARY OF BACKGROUND DATA: Acute low back pain usually resolves spontaneously, but the recurrence rate is high. Inhibition of multifidus occurs with acute, first-episode, low back pain, and pathologic changes in this muscle have been linked with poor outcome and recurrence of symptoms. METHODS: Patients in group 1 received medical treatment only. Patients in group 2 received medical treatment and specific, localized, exercise therapy. Outcome measures for both groups included 4 weekly assessments of pain, disability, range of motion, and size of the multifidus cross-sectional area. Independent examiners were blinded to group allocation. Patients were reassessed at a 10-week follow-up examination. RESULTS: Multifidus muscle recovery was not spontaneous on remission of painful symptoms in patients in group 1. Muscle recovery was more rapid and more complete in patients in group 2 who received exercise therapy (P = 0.0001). Other outcome measurements were similar for the two groups at the 4-week examination. Although they resumed normal levels of activity, patients in group 1 still had decreased multifidus muscle size at the 10-week follow-up examination. CONCLUSIONS: Multifidus muscle recovery is not spontaneous on remission of painful symptoms. Lack of localized, muscle support may be one reason for the high recurrence rate of low back pain following the initial episode.

Responses to mechanical stimulation of the upper limb in painful cervical radiculopathy, Hall T, Quintner J.

Aust J Physiother. 1996;42(4):277-285.

Abstract: Clinical and electromyographic (EMG) responses to non-noxious mechanical stimuli were studied in four patients with painful cervical radiculopathy, and in two control subjects. In the symptomatic arm(s), palpation over one or more nerve trunks was painful and accompanied by EMG activity, whereas palpation of adjacent soft tissues was painless and unaccompanied by EMG activity. Electromyographic activity was widespread in three patients when myotatic reflexes were elicited in the symptomatic arm(s). In asymptomatic arms of patients and controls, EMG responses to the myotatic reflexes were more localised. Allodynic nerve trunks in cervical radiculopathy appear to be afferent correlates of central sensitization; the accompanying EMG activity may represent a motor correlate of this same process.

Comment: Muscles throughout the area of the brachial plexus are commonly found inhibited or atrophying after cervical spine injury and inflammation. Patients who have experienced cervical trauma from whiplash and other dynamics often have perplexing symptoms. This leads some doctors who do not evaluate function to conclude that poor response to therapy is psychogenic and often related to the patient's conscious or subconscious effort to gain in the medicolegal process. The standard orthopedic and neurologic examination often does not find a cause for the bizarre symptoms about which some patients complain. Manual muscle testing is a method for evaluating the function of the nervous system; it often reveals the cause, giving an understanding of the patient's many complaints.

Suboccipital dermatomyotomic stimulation and digital blood flow, Purdy WR, Frank JJ, Oliver B.

J Am Osteopath Assoc. 1996 May;96(5):285-9.

Abstract: The effect of gentle, soft tissue manipulation in the suboccipital region on digital blood flow, as a measure of sympathetic nervous system activity, was studied. Digital strain gauge plethysmography was used to measure the changes in pulse contour during (1) a normative test period with the subject in the supine position, (2) after a control interval (placebo) during which the investigator placed his hands under the suboccipital region, and (3) after an interval during which the investigator's fingers applied slow, steady, circular kneading in the suboccipital triangle region. Twenty-five studies were performed in a crossover design with the patient as his or her own control. Total pulse amplitude (Y) and the height from the dicrotic notch to the peak (X) were measured. Examination of the total data of all subjects revealed the occurrence of a significant change in X and Y with simply touching the suboccipital region with the hands. An even more favorable response ensued when suboccipital manipulation was applied. Those subjects reporting comfort or neutral responses had larger significant changes with manipulation when compared with the group reporting the experience as uncomfortable. The response within each group suggests that favorable autonomic changes (sympathetic dampening) occur with specific suboccipital manipulation as well as, indeed, the simple touching of the suboccipital triangle.

Comment: The AK technique called jugular decompression works specifically with the tissues of the suboccipital triangle. Treatment to any of the 5-factors of the IVF that improves the tone of the muscles in this area may produce the positive effects noted in this study.

Postural stability following mild head or whiplash injuries, Rubin AM, Woolley SM, Dailey VM, Goebel JA.

Am J Otol. 1995 Mar;16(2):216-21.

Abstract: Studies of the sequelae of head injury suggest that cochlear and vestibular dysfunctions, comprise some of the most frequently reported delayed complications following head trauma. To date, little attention has been given to the relation between post-traumatic subjective symptoms of dizziness and the objective measures of postural stability or balance. The purpose of this study was to quantify the balance deficits in individuals who had developed symptoms of dizziness following mild head and whiplash injuries. The balance abilities of 29 patients, who developed dizziness following some type of mild head or whiplash injury, were compared to those of 51 healthy symptom-free subjects. Balance was assessed by examining the center-of-pressure movements, in the anterior-posterior and medial-lateral directions, and the total movement displacement. The isolated contributions of visual and somatosensory inputs were estimated by comparing the magnitudes of the center-of-pressure movements for the various sensory conditions. Data were collected from three 30-second trials of each combination of three visual conditions (accurate, absent, and inaccurate) and two somatosensory conditions (accurate and inaccurate), with the patient standing on a fixed-force platform. Univariate analyses of variance indicated that the group with head injury, compared to the control group, exhibited significantly greater anterior-posterior movements in four of the six sensory conditions and greater total movement displacement during the inaccurate vision/inaccurate somatosensation condition. These data suggest that patients who have sustained head or neck trauma exhibit increased reliance on accurate visual input and are unable to utilize vestibular orienting information to resolve conflicting information from the visual and somatosensory systems.

Comment: Goodheart introduced the Freeman-Wyke one-leg standing test into AK in 1989. The patient is asked to stand upon one foot in front of the doctor, to find their balance if they can, and then to close their eyes.  If they lose their balance, the test is positive. Upon asking the patient to therapy localize to the cervical spine, they may immediately improve their balance. The Freeman Wyke one-leg standing test is a functional neurological evaluation that requires the integrated function of various proprioceptors all over the body. These complex types of challenges are an important part of the differential diagnostic information that a physician using AK methods can employ to determine dysfunction in the sensory-motor-postural-proprioceptive systems in patients with post-whiplash syndromes.

Sacroiliac joint manipulation decreases the H-reflex, Murphy, B.A., Dawson, N.J., Slack, J.R.

Electromyogr Clin Neurophysiol, 1995;35:87-94

Abstract: Joint manipulation is widely utilized clinically to decrease pain and increase the range of motion of joints displaying limited mobility. Evidence of efficacy is based on subjective reports of symptom improvement as well as on the results of clinical trials. Experiments were designed to determine whether or not sacroiliac joint manipulation affects the amplitude of the Hoffman (H) reflex. Surface EMG recordings of the reflex response to electrical stimulation of the tibial nerve in the popliteal fossa were made from the soleus muscle. The averaged amplitudes of H-reflexes were compared on both legs before and after either sacroiliac joint manipulation or a sham procedure. H-reflex amplitude was significantly decreased (12.9%) in the ipsilateral leg (p < 0.001) following a sacroiliac joint manipulation while there was no significant alteration following the sham intervention. There was no significant alteration in reflex excitability in the contralateral leg to the sacroiliac joint manipulation. To further investigate the mechanism of these reflex alterations, the local anesthetic cream EMLA (Astra Pharmaceuticals) was applied to the skin overlying the sacroiliac joint and the experiments were repeated on a different group of subjects. This was intended to determine if excitation of cutaneous afferents was responsible for the reflex excitability changes. There was still a significant decrease in reflex excitability (10.6%) following sacroiliac joint manipulation (p < 0.001). These findings indicate that joint manipulation exerts physiological effects on the central nervous system, probably at the segmental level. The fact that the changes persisted in the presence of cutaneous anesthesia suggests that the reflex changes are likely to be mediated by joint and/or muscle afferents.

Comment: This study offers further elucidation of the finding of the physiological response of muscles to sacroiliac manipulation. One basic physiologic response to spinal manipulative therapy is a transient decrease or increase in motoneuron activity as assessed by the Hoffmann reflex (H-reflex) technique, depending upon the patients neuromuscular status at the time of measurement. The H-reflex technique involves peripheral stimulation of the Ia-afferent feedback pathway to assess the excitability of the alpha motoneuron. The MMT in AK evaluates the same neurological mechanism. This study shows that the clinical efficacy of SMT may involve a change in motoneuron activity which, in turn, may lead to a reduction in hypertonic as well as an increase in hypotonic muscles. Thus, a basic neurophysiologic response to SMT is muscular response to treatment.

Flexion-relaxation phenomenon in the back muscles. A comparative study between healthy subjects and patients with chronic low back pain, Shirado O, Ito T, Kaneda K, Strax TE.

Am J Phys Med Rehabil. 1995 Mar-Apr;74(2):139-44.

Abstract: At a certain position of trunk flexion, there is a sudden onset of electrical silence in back muscles. This is called "flexion-relaxation (F-R) phenomenon." The goals of this study were (1) to evaluate the relationship between flexion angle and activity of back muscles during flexion movement and (2) to determine what the difference is between healthy subjects and patients with chronic low back pain (CLBP). Twenty-five healthy subjects (13 males and 12 females; average age, 28.3 yr) and 20 patients with CLBP (12 males and 8 females; average age, 34.1 yr) volunteered for this study. The subjects were asked to flex forward maximally from the erect position and to maintain full flexion, followed by returning to the initial upright position. Flexion angle of trunk and hip was measured during the examination. Electromyographic activity of erector spinae was also monitored simultaneously. F-R phenomenon was observed in all healthy subjects before reaching the maximum flexion. Electrical silence continued even after extending the trunk began. In contrast, no patients with CLBP demonstrated F-R phenomenon. A significant difference in muscular activities of erector spinae between the groups was obtained when returning to the erect position from the maximum flexion. Moreover, time lag between trunk and hip movement was much greater in patients than in healthy subjects. This study demonstrated that neuromuscular coordination between trunk and hip could be abnormal in patients with CLBP.

Comment: The key technical factor in the examination of patients with CLBP would be the MMT that makes the detection of the muscular imbalances and aberrant muscular activation patterns cited in this paper identifiable.

Changes in neck electromyography associated with meningeal noxious stimulation, Hu JW, Vernon H, Tatourian I.

J Manipulative Physiol Ther. 1995 Nov-Dec;18(9):577-81.

OBJECTIVE: To determine if the activity of jaw and neck muscles in a rat model is influenced by the application of small-fiber irritant mustard oil to meningeal/dural vascular tissues. DESIGN: Controlled animal experiment. SETTING: University neurophysiology laboratory. INTERVENTIONS: Applications of mineral oil (vehicle control) and mustard oil to exposed meningeal/dural vascular tissues. MAIN OUTCOME MEASURE: Electromyographic (EMG) recordings from deep suboccipital muscles, bilaterally, and the left trapezius and left masseter muscles. RESULTS: Mineral oil evoked no EMG responses in any muscles. The incidences of mustard oil-evoked EMG increases were 100%, 100%, 89% and 78% for left deep neck, right deep neck, left trapezium and left masseter muscles, respectively. The durations of EMG responses were (mean +/- SD) 19.2 +/- 6.6 min, 17.3 +/- 7.5 min, 14.5 +/- 6.8 min and 12.7 +/- 8.5 min, respectively. CONCLUSIONS: These results document that meningeal/dural vascular irritation leads to sustained and reversible activation of neck and jaw muscles that may be related to the clinical occurrence of muscular tension and pain associated with certain types of headaches, particularly migraine.

The influence of afferent inputs from skin and viscera on the activity of the bladder and the skeletal muscle surrounding the urethra in the rat, Morrison JF, Sato A, Sato Y, Yamanishi T.

Neurosci Res. 1995 Sep;23(2):195-205

(1) Somato-visceral and viscero-visceral reflex interactions have been studied in the bladder branches of the pelvic nerve and in the electromyographic (EMG) activity of the periurethral skeletal muscles of the anesthetized rat, and by observations of changes in bladder motility. (2) Slow distensions of the bladder caused some elevation of intravesical pressure, and culminated in a micturition contraction. Periurethral EMG activity increased gradually during the bladder distension, and showed an oscillatory marked increase during the bladder contraction. There was a small increase in pelvic nerve efferent activity during slow distension, and there was a substantial increase before, or at the start, of a micturition contraction. (3) Oscillatory bursting activity occurred in recordings of the EMG activity from periurethral skeletal muscle during the rising phase of micturition contraction; this was particularly so during the most rapid rise in intravesical pressure, and periods of electrical silence lasting 80-270 ms alternated with bursts of activity in the periurethral EMG. (4) In the present experiments, the switching mechanism activated by pelvic afferent signals related to intravesical pressure reversed the behavior of a number of reflex pathways. When the bladder pressure was low, nociceptive pinching of the perineal skin usually caused bladder contraction and a rise in pelvic nerve efferent activity and in periurethral EMG activity. When the bladder was full, micturition contractions were present and reduced in size and frequency by pinching of the perineal skin. The pelvic nerve efferent activity was correspondingly reduced, while the EMG activity increased during and following the nociceptive stimulus. Cooling the scrotal skin with ice also decreased the frequency of bladder contractions. (5) When the bladder pressure was low, distension of the anus and colon increased periurethral EMG activity, but did not affect bladder tone. However, when the bladder was full, these stimuli reduced the size and frequency of bladder contractions, associated with a reduction in the pelvic nerve efferent activity. There was usually a simultaneous reduction in the EMG activity in periurethral muscles. Similar results were obtained during distension of the seminal vesicles or vagina, or following injection of 20-60 microliters of saline into the lumen of the vas deferens. Reversal of the responses at extremes of intravesical pressure was observed in every case. (6) Following spinal transection at the upper cervical or thoracic level, micturition contractions were absent at high bladder volumes. However the effects described when the neuraxis was intact and the bladder pressure was low were still observed.

Comment: A crucial development in AK occurred when Goodheart observed that if a patient touched an area of dysfunction, the results of MMT changed. Therapy localization has numerous applications in AK including TL to various reflexes, subluxations, meridian points, nerve receptors and other areas. This paper explains part of this fascinating development in the healing arts that has been proven helpful in the diagnosis of physical dysfunctions in patients.

The role of the psoas and iliacus muscles for stability and movement of the lumbar spine, pelvis and hip, Andersson E, Oddsson L, Grundstrom H, Thorstensson A.

Scand J Med Sci Sports. 1995 Feb;5(1):10-6

Abstract: The activation patterns of the psoas and iliacus muscles were investigated in 7 healthy adult subjects (4 men and 3 women) during a variety of motor tasks in standing, sitting and lying. Myoelectric activity was recorded simultaneously from the 2 muscles using thin wire electrodes inserted under guidance of high-resolution ultrasound. In general, both muscles were coactivated, albeit to different relative levels, particularly when hip flexor torque was required. Selective activation of the iliacus could, however, be seen to stabilize the pelvis in contralateral hip extension during standing. Psoas was found to be selectively involved in sitting with a straight back and in contralateral loading situations requiring stabilization of the spine in the frontal plane. During training exercises from a supine position, such as sit-ups, the contribution of the psoas and iliacus muscles could be varied by changing the range of motion as well as the position and support for the legs. Thus, the 2 anatomically different muscles of the iliopsoas complex were shown to have individual and task-specific activation patterns depending on the particular demands for stability and movement at the lumbar spine, pelvis and hip.

Shoulder weakness in professional baseball pitchers,

Magnusson SP, Gleim GW, Nicholas JA.

Med Sci Sports Exerc. 1994 Jan;26(1):5-9.

Abstract: The purposes of this study were to: 1) compare shoulder range of motion and strength in professional baseball pitchers (N = 47) compared with age-matched controls (N = 16), and 2) examine the relationship of injury history to strength and range of motion. Based on injury history pitchers were categorized as: 1) none (N = 26), 2) injury requiring conservative intervention (N = 9), or 3) injury requiring surgical intervention (N = 12). Range of motion was measured for internal rotation (IROM) and external rotation (EROM). Eccentric strength was measured by hand-held dynamometer for internal rotation (IR), external rotation (ER), abduction (ABD), and supraspinatus muscle (SUP) strength. Injury history had no effect on strength and range of motion. Dominant EROM was greater in pitchers, P < 0.0001, and controls, P < 0.05, with pitchers having greater EROM motion bilaterally, P < 0.0001. Pitchers were weaker in SUP on the dominant vs nondominant side, P < 0.0001, and on the dominant side for weight adjusted ER, ABD, P < 0.01, and SUP, P < 0.0001, compared with controls. In conclusion, dominance and pitching resulted in soft tissue adaptation. Pitchers displayed weakness in three of four tests by comparison with controls, suggesting that the demands of pitching are insufficient to produce eccentric strength gains and may in fact lead to weakness. Dominant-side SUP weakness in pitchers may reflect subclinical pathology or chronic fatigue.

Thermal deficit in lumbar radiculopathy. Correlations with pain and neurologic signs and its value for assessing symptomatic severity, Takahashi Y, Takahashi K, Moriya H.

Spine. 1994 Nov 1;19(21):2443-9; discussion 2449-50.

STUDY DESIGN. The relationship between areas of thermal deficit and areas exhibiting other symptoms and neurologic signs, and the significance of the magnitude of thermal deficit in lumbar radiculopathy were analyzed. OBJECTIVES. To determine the clinical significance and value of thermal deficit as a sign of lumbar radiculopathy. SUMMARY OF BACKGROUND DATA. Thermal deficit has been discussed as a factor in the diagnosis of involved nerve roots. However, it has not been previously correlated with any particular symptoms or signs. METHODS. Sixty-eight healthy subjects and one hundred nine patients with lumbar radiculopathy due to intervertebral disc herniation underwent thermography. Sensitivity, specificity, and the agreement rate of thermal deficit to symptoms and neurologic signs were calculated in ten body regions. Total temperature difference of the affected limb was compared with the Japanese Orthopaedic Association scoring system. RESULTS. The agreement rates of thermal deficit with pain, muscle tenderness, motor weakness, and sensory disturbance were 60.9, 69.3, 71.8, and 71.8%, respectively. Sensitivity and specificity of thermal deficit to symptoms and signs were approximately 30% and 80%, respectively. The correlation coefficient of temperature decrease of the affected limb and the Japanese Orthopaedic Association score was 0.57, indicating a moderate correlation. CONCLUSIONS. Thermal deficit should be considered an independent sign of lumbar radiculopathy. The relatively high specificity suggests that a normal temperature may indicate an asymptomatic region. Symptomatic severity of lumbar radiculopathy may be assessed by measuring the magnitude of thermal deficit in the affected limb.

Comment: The correspondence between thermal deficit and motor weakness was the highest correlation cited in this study, indicating that measuring motor weakness in the affected limb may also assess the severity of lumbar radiculopathy. This study showed that disturbances of muscle function change skin temperature readings also.

The role of sensory information in the guidance of voluntary movement, McCloskey, D.I., Prochazka, A.

Somatosensory and Motor Research, 1994;11:69-76

Abstract: For voluntary movements to be well timed and accurate, they require coordinated tactile, visual and proprioceptive information about the movement in progress. Locomotion should be a stable cycle generated by the sensory links between the musculoskeletal system, the neural system and the environment.

Cervical musculoskeletal dysfunction in post-concussional headache, Treleaven J, Jull G, Atkinson L.

Cephalalgia, 1994 Aug;14(4):273-9; discussion 257.

Abstract: Persistent headache is a common symptom following a minor head injury or concussion, possibly related to simultaneous injury of structures of the cervical spine. This study measured aspects of cervical musculoskeletal function in a group of patients (12) with post-concussional headache (PCH) and in a normal control group. The PCH group was distinguished from the control group by the presence of painful upper cervical segmental joint dysfunction, less endurance in the neck flexor muscles and a higher incidence of moderately tight neck musculature. Active range of cervical motion and postural attitude were not significantly different between groups. As upper cervical joint dysfunction is a feature of cervicogenic causes of headache, the results of this study support the inclusion of a precise physical examination of the cervical region in differential diagnosis of patients suffering persistent headache following concussion.

Comment: The need for specific and reliable clinical tests for cervical muscular function is highlighted in this paper. Tests that are cost-effective and reliable provide the practitioner with a powerful tool for initial examination, and for repeated tests to measure the effectiveness of treatment. The complexity of injury in PCH is such that a system of diagnosis and treatment has been developed in AK that encompasses a wide range of modalities.

Isokinetic Muscle Testing: Is It Clinically Useful?, Almekinders LC, Oman J.

J Am Acad Orthop Surg,  1994 Jul;2(4):221-225.

Abstract: The use of computer-driven muscle-testing devices has become increasingly popular during the past two decades. This expensive equipment allows evaluation of muscles and muscle groups in an isokinetic manner. Isokinetic muscle testing is performed with a constant speed of angular motion but variable resistance. Isokinetic dynamometers have been shown to produce relatively reliable data when testing simple, uniaxial joints, such as the knee, as well as when testing the spine in flexion and extension. Isokinetic strength data are generally not helpful in the diagnosis of orthopedic abnormalities. Isokinetic testing can be helpful during the rehabilitation of orthopedic patients, since it allows easy monitoring of progress. It also enables the patient to work on muscle rehabilitation in a controlled manner at higher speeds than are possible with more conventional exercise equipment. An isokinetic rehabilitation program can be easily tailored with concentric and eccentric components that closely resemble muscle actions during occupational and sports activities.

Arthrogenic quadriceps inhibition and rehabilitation of patients with extensive traumatic knee injuries, Hurley M, Jones D, Newham D

Clin Sci (Lond).1994 Mar;86(3):305-10.

Abstract: 1. The relationship between joint damage, quadriceps weakness and arthrogenic muscle inhibition was investigated in eight patients who had sustained extensive traumatic knee injury. Isometric and isokinetic quadriceps and hamstring voluntary strength, and quadriceps arthrogenic muscle inhibition during isometric contractions, were measured before and after 4 weeks (approximately 100 h) of intensive rehabilitation. 2. Compared with the uninjured leg, before rehabilitation the injured leg had larger amounts of quadriceps arthrogenic muscle inhibition (P < 0.025), quadriceps (P < 0.0001) and hamstring (P < 0.0001) weakness and severe functional joint instability. There was a negative correlation between the amount of arthrogenic muscle inhibition and quadriceps voluntary contraction force (P < 0.025). 3. After rehabilitation in the injured leg there were small hamstring strength increases (P < 0.05-0.025), but no overall significant quadriceps strength increase. Arthrogenic muscle inhibition was statistically unchanged. Severe functional joint instability was still reported by all patients. 4. Previous studies have shown that minimal joint damage evokes relatively less arthrogenic muscle inhibition that does not impede rehabilitation. These data indicate that greater joint damage is associated with greater arthrogenic muscle inhibition, quadriceps weakness and joint instability. Furthermore, intensive rehabilitation had little affect on either quadriceps arthrogenic muscle inhibition or atrophy.

Comment: This study indicates that specific injuries to the knee joint produce measurable inhibitions of quadriceps and hamstring muscles. This is a central tenet of AK, i.e. that joint injuries will produce muscle weakness that can be specifically diagnosed and treated. On a clinical basis, AK physicians find this consistently when testing patients with knee injuries. The fact that rehabilitation did not improve the arthrogenic inhibition found in these patients may indicate that the totality of their joint and muscle problems in the knee was not adequately treated.

Atrophy of suboccipital muscles in patients with chronic pain: a pilot study, Hallgren RC, Greenman PE. Rechtien JJ.

J Am Osteopath Assoc. 1994 Dec;94(12):1032-8.

Abstract: Magnetic resonance imaging studies were performed in six patients with chronic head and neck pain and in five control subjects to determine whether irreversible atrophic changes resulting in destruction of muscle fibers have a role in patients with chronic pain specific to the cervical spine. Both groups of subjects had medical history obtained and underwent physical examination and proton density-weighted (PD-weighted) magnetic resonance imaging. Subjects with chronic pain had substantial restriction of motion. Axial proton density-weighted images of the rectus capitis major and minor muscles were examined. In the subjects with chronic pain, the muscles had high signal intensity, indicating replacement of dead suboccipital skeletal muscle with fatty tissue. This infiltration was not observed in the control subjects who were free of significant motion restrictions and had no history of recurring neck and head pain. Analysis of pixel intensity values confirmed this finding. The reduction in proprioceptive afferent activity in affected muscles may cause increased facilitation of neural activity that is perceived as pain. At least mean squares algorithm was used to define a linear estimating equation for each subject. Linear regression analysis, using an alpha level < .005, was used to determine how well each subject's data fit the estimating equation. This preliminary work indicates substantial infiltration of fatty tissue into suboccipital muscles of some subjects being treated for chronic head and neck pain.

Evidence of lumbar multifidus muscle wasting ipsilateral to symptoms in patients with acute/subacute low back pain, Hides JA, Stokes MJ, Saide M, Jull GA, Cooper DH.

Spine. 1994 Jan 15;19(2):165-72.

Abstract: The effect of low back pain on the size of the lumbar multifidus muscle was examined using real-time ultrasound imaging. Bilateral scans were performed in 26 patients with acute unilateral low back pain (LBP) symptoms (aged 17-46 years) and 51 normal subjects (aged 19-32 years). In all patients, multifidus cross-sectional area (CSA) was measured from the 2nd to the 5th lumbar vertebrae (L2-5) and in six patients, that of S1 was also measured. In all normal subjects, CSA was measured at L4 and in 10 subjects measurements were made from L2-5. Marked asymmetry of multifidus CSA was seen in patients with the smaller muscle being on the side ipsilateral to symptoms (between-side difference 31 +/- 8%), but this was confined to one vertebral level. Above and below this level of wasting, mean CSA differences were < 6%. In normal subjects, the mean differences were < 5% at all vertebral levels. The site of wasting in patients corresponded to the clinically determined level of symptoms in 24 of the 26 patients, but there was no correlation between the degree of asymmetry and severity of symptoms. Patients had rounder muscles than normal subjects (measured by a shape ratio index), perhaps indicating muscle spasm. Linear measurements of multifidus cross-section were highly correlated with CSA in normal muscles but less so in wasted muscles, so CSA measurements are more accurate than linear dimensions. The fact that reduced CSA, i.e., wasting, was unilateral and isolated to one level suggests that the mechanism of wasting was not generalized disuse atrophy or spinal reflex inhibition.

Comment: The researchers in this paper have found lumbar multifidus muscle atrophy occurs in patients with low back pain. In this study, no therapy for this finding was offered, and the functional state of these muscles was not evaluated. Were the muscles neurologically inhibited or facilitated; were they capable to functioning better? AK has presented the new principle that the scientific literature had not previously dealt with; the correct form of manual treatment can instantly improve muscle function.

The influence of ankle sprain injury on muscle activation during hip extension, Bullock-Saxton JE, Janda V, Bullock MI.

Int J Sports Med. 1994 Aug;15(6):330-4.

Abstract: The likely influence of a localized injury in a distal joint on the function of proximal muscles is an important consideration in assessment and treatment of musculoskeletal injuries. However, little experimental evidence in humans exists in this area. Accordingly, a controlled study was carried out, in which the function of muscles at the hip was compared between subjects who had suffered previous severe unilateral ankle sprain and matched control subjects. The pattern of activation of the gluteus maximus, the hamstring muscles and the ipsilateral and contralateral erector spinae muscles was monitored through the use of surface electromyography during hip extension from prone lying. Analyses revealed that the pattern of muscle activation in subjects with previous injury differed markedly from normal control subjects, and that changes appeared to occur on both the uninjured and the injured sides of the body. A significant difference between the two groups was the delay in onset of activation of the gluteus maximus in previously injured subjects. The existence of remote changes in muscle function following injury found in this study emphasise the importance of extending assessment beyond the side and site of injury.

Various Forms of Chiropractic Technique, Bergmann, T.

Chiropractic Technique, May 1993; 5(2):53-5.

Neuromuscular effects of temporomandibular joint dysfunction, Esposito, V., Leisman G, Frankenthal Y.

Intern J Neuroscience, 1993;68

Abstract: Neurologically intact male and female TMJ dysfunction patients with or without cervical spine involvement were examined using standard clinical neurologic testing for balance and coordination. Seventy percent of the TMJ patients without cervical involvement exhibited positive signs for balance, coordination, and/or ataxia found in response to having the patient’s mandible stressed by extending it a far as possible laterally, and also opened (as wide as possible) or closed (biting down). The performance of patients with cervical involvement was not significantly different than those without cervical involvement. Further examination of the relation between the TMJ and auditory, visual, cerebellar, and coordination mechanisms is therefore indicated.

Cervical headache: an investigation of natural head posture and upper cervical flexor muscle performance, Watson DH, Trott PH

Cephalalgia, 1993 Aug;13(4):272-84; discussion 232.

Abstract: In this study, 60 female subjects, aged between 25 and 40 years, were divided into two equal groups on the basis of absence or presence of headache. A passive accessory intervertebral mobility (PAIVM) examination was performed to confirm an upper cervical articular cause of the subjects' headache and a questionnaire was used to establish a profile of the headache population. Measurements of cranio-cervical posture and isometric strength and endurance of the upper cervical flexor muscles were compared between the two groups of subjects. The headache group was found to be significantly different from the non-headache group in respect to forward head posture (FHP) (t = -5.98, p < 0.00005), less isometric strength (t = 3.43, p < 0.001) and less endurance (t = 8.71, p < 0.0005) of the upper cervical flexors. A statistically significant relationship was also established between natural head posture and isometric endurance of the upper cervical flexor musculature which demonstrated that FHP corresponded with a low endurance capacity (chi 2 = 13.2; p < 0.01). The outcome of this study highlights the need to screen for cervical etiology in patients who are suspected of suffering from common migraine.

The influence of arthrogenous muscle inhibition on quadriceps rehabilitation of patients with early, unilateral osteoarthritic knees, Hurley MV, Newham DJ.

Br J Rheumatol, 1993 Feb;32(2):127-31.

Abstract: Reflex arthrogenous muscle inhibition (AMI) may cause muscle atrophy or impede effective rehabilitation of affected muscle groups. To investigate this, bilateral quadriceps AMI, isometric and isokinetic muscle strength were measured in 10 patients with unilateral osteoarthritic knees, before and after a course of routine physiotherapy. Before rehabilitation, quadriceps of all the diseased legs were inhibited (P < 0.05) and 40% weaker (P < 0.02) than the non-diseased legs. Following rehabilitation, AMI decreased (P < 0.01) in the diseased leg and strength increased at all test velocities (P < 0.05-0.005); however, strength deficits compared with the non-diseased leg remained. Subjective improvements in functional ability and confidence in the diseased leg were reported. Though AMI may be partially responsible for unilateral muscle weakness, it does not preclude strength gain in affected muscles. Possible physiological mechanisms which evoke AMI may also adversely affect muscle proprioception, implicating AMI as a possible cause of initiation or progression of degenerative joint disease.

Comment: This study demonstrates that being able to reduce arthrogenous muscle inhibition in patients recovering from joint injuries is important to the rehabilitation process. It also shows that a measurable change in muscle strength, from inhibition to strength, occurs after manipulative therapy. AMI is the inability of a muscle to recruit all motor units of a muscle group during a maximal effort voluntary muscle contraction and it is a natural response designed to protect joints from further damage. The AMI phenomenon is frequently found during AK evaluations when there is muscle weakness around joints that have been injured. Mechanoreceptor activity plays a primary role in AMI. Manipulation of a joint has been shown to activate mechanoreceptors from structures in and around the manipulated joint. The altered afferent input arising from the stimulation of these receptors is thought to cause changes in motor neuron excitability, with a subsequent decrease in AMI. This is assumed to influence motor neuron pool recruitment during voluntary muscle contraction.

Reflex activation of gluteal muscles in walking. An approach to restoration of muscle function for patients with low-back pain, Bullock-Saxton JE, Janda V, Bullock MI.

Spine, 1993 May;18(6):704-8.

Abstract: Gluteal activation and pelvic stability often are decreased in chronic low-back pain sufferers, but the importance of motor control and programming in treatment has not been fully evaluated. This study investigated whether gluteal muscles could be activated more effectively by stimulating the proprioceptive mechanism during walking. Labile support, through wearing "balance shoes," offered facilitation of cerebellovestibular circuits. Electromyographic recordings of gluteus maximus and medius in 15 healthy subjects were made during barefoot and balance shoes walking before and after 1 week of facilitation. Significant increases (P < 0.0002) in gluteal activity and significant decreases (P < 0.01) in time to 75% maximum contraction, demonstrated the value of sensorimotor elicitation of subconscious and automatic responses in muscles often weakened in back pain sufferers.

Comment: AK adds a dynamic aspect to orthopedic examination as it relates to the extremities. Knowledge of predictable muscle function resulting from stimulating the foot proprioceptors (the object of this study) helps understand how subluxations and muscle dysfunction of the feet affect remote areas of the body.

Childhood psychological trauma and chronic refractory low-back pain, Schofferman J, Anderson D, Hines R, Smith G, Keane G.

Clin J Pain. 1993 Dec;9(4):260-5.

OBJECTIVE: To examine the correlation between childhood psychological trauma(s) and refractory back pain in patients with and patients without prior spine surgery. DESIGN: Retrospective chart review survey of 101 consecutive patients who had undergone multidisciplinary evaluation for refractory back pain. SETTING: Private practice, tertiary care spine center. MAIN OUTCOME MEASURES: Each psychological risk factor (physical abuse, sexual abuse, emotional neglect or abuse, abandonment, and chemically dependent caregiver) was rated as present or absent. Spinal pathology was graded as significant or not significant. RESULTS: There were 56 patients with failed back surgery syndrome, 28 men and 28 women, with a mean age of 43 and mean pain duration of 45 months. There were 45 patients with no prior surgery, 26 men and 19 women, with a mean age of 43 and mean pain duration of 33 months. In the failed back surgery syndrome group, 27 (48%) had three or more risks and 39 (70%) had two or more. When the 12 patients with significant pathology are not considered, 24 of the remaining 44 (55%) patients had three or more risks. In the group with no prior surgery, 26 (58%) had three or more risks and 38 (84%) had two or more. When the five patients with significant pathology are not considered, 24 (60%) had three or more risks. CONCLUSIONS: Multiple childhood psychological traumas may predispose a person to chronic low back pain. In patients in this setting with refractory low back pain with or without prior lumbar spine surgery, three or more childhood psychological risk factors are prevalent, especially in patients with minimal structural pathology.

Chronic musculoskeletal pain and depressive symptoms in the National Health and Nutrition Examination. I. Epidemiologic follow-up study, Magni G, Marchetti M, Moreschi C, Merskey H, Luchini SR.

Pain. 1993 May;53(2):163-8.

Abstract: We report here follow-up data on subjects who were examined in two surveys conducted by the United States Center for Health Statistics at an interval of 8 years. The first survey was the 1st National Health and Nutrition Examination Survey (NHANES-1), and the second conducted 8 years later was the National Health and Nutrition Epidemiologic Follow-up Study (NHEFS). From an original sample of 3023 subjects, 153 were known to be deceased, leaving a potential sample of 2870 cases, of whom 2341 were ultimately examined in the NHEFS. The definition of pain used in the NHANES-1 survey identified 15% of the subjects as suffering from persistent pain. Using a different pain definition, in the NHEFS, the frequency of subjects with chronic pain was 32.8%. Applying this second definition, the percentage of subjects with chronic pain in the NHANES-1 had risen from 15 to 20.2. Some subjects (32.5%) who originally had chronic pain were free from pain at the time of follow-up; 59% of the subjects with chronic pain on follow-up did not have it initially. As found originally in the NHANES-1, the group with chronic pain at the NHEFS comprised significantly more females, older people, and people with lower income. On logistic regression analysis the strongest relationship found at the NHEFS between the variables examined was between chronic pain and depression.

Comment: In AK examination it is frequently found that many mental and emotional problems are due to physiological dysfunction. This paper highlights the fact that depression and other psychological concomitants to spinal pain may be resolved with successful chiropractic treatment to the patient’s pain syndromes.

Cervical spine subluxation associated with congenital muscular torticollis and craniofacial asymmetry, Slate RK, Posnick JC, Armstrong DC, Buncic JR.

Plast Reconstr Surg. 1993 Jun;91(7):1187-95; discussion 1196-7.

Abstract: The relationship between craniofacial asymmetry, congenital muscular torticollis, and cervical spine subluxation was examined in a study of 30 children who presented to our Craniofacial Program from 1987 through 1990. Twenty-six of the 30 patients had craniofacial asymmetry and muscular torticollis without true suture synostosis documented by head and neck CT scans. These 26 patients had positional skull molding with consistent flattening of the contralateral occipitoparietal region and the ipsilateral fronto-orbital region relative to the side of the torticollis. Thirteen of the 26 patients also were found to have a C1-C2 subluxation. C1 was rotated forward of C2 on the side contralateral to the muscular torticollis in 12 of 13 patients. None of the patients with subluxation had neurologic deficits or required spinal stabilization. Ophthalmologic evaluations demonstrated amblyopia (4 patients) and horizontal strabismus (1 patient), both thought to be coincidental, with no evidence of nystagmus in any case. Seven of the 26 patients required surgical therapy for their neck muscle tightness, while the remainder responded to physiotherapy. Only 2 of the 26 patients underwent cranio-orbital reshaping for correction of their upper face asymmetry. Recognition of cervical subluxation in patients with congenital muscular torticollis may help to explain residual head-neck posturing problems even after successful neck muscle therapy.

The lumbar multifidus muscle five years after surgery for a lumbar intervertebral disc herniation, Rantanen J, Hurme M, Falck B, Alaranta H, Nykvist F, Lehto M, Einola S, Kalimo H.

Spine. 1993 Apr;18(5):568-74.

Abstract: Biopsy specimens of the lumbar multifidus were obtained from 18 patients with lumbar disc herniation at operation and after a postoperative follow-up period of 5 years. The structure and morphometry of the muscle fibers were analyzed and these data were compared with intraoperative biopsy results and the clinical outcome of the operation. The main findings were: 1) on the basis of occupational handicap score 10 patients belonged in the "positive" and 8 in the "negative" outcome group; 2) the intraoperatively recorded selective type 2 muscle fiber atrophy and the extent of pathologic inner structure changes both decreased in the "positive" outcome group, whereas they persisted in the "negative" group; 3) grouping as a definite sign of reinnervation was seen in only two versus four patients of the "positive" versus "negative" outcome group; 4) the relative amount of adipose tissue within the muscle decreased more markedly in the "positive" outcome group. The authors propose that both inactivity and axonal injury (mainly of neurapraxia type) contribute to the selective type 2 atrophy and inner structure changes in disc patients' multifidus muscle. These pathologic structural changes correlated well with the clinical outcome, and most importantly they are reversible and can be diminished by adequate therapy.

The effects of neutral posture deviations on perceived joint discomfort ratings in sitting and standing postures, Genaidy AM, Karwowski W.

Ergonomics. 1993 Jul;36(7):785-92.

Abstract: There is a pressing need to rank body deviations from neutral postures which occur due to variety of body movements around different joints. Such knowledge is needed to better understand potentially adverse effects of poor working postures on the industrial population. The main objective of this study was to examine the effects of postural deviations on perceived joint discomfort ratings assessed under similar working conditions. Twelve males and seven females participated in the laboratory study. The results revealed several distinct classes of joint deviations from neutral postures, which need to be assigned different weights of postural stress. A preliminary ranking system for assessment of stressfulness of human body deviations about different joints was proposed.

Comment: Postural analysis is a major source of information in AK. It is one of several methods for locating probable muscle dysfunction. As one becomes more familiar with AK, nearly all postural imbalances can be readily understood as a result of aberrant muscle function in nearly all cases.

The reflex effects of spinal somatic nerve stimulation on viscera function, Sato, A.

J Manipulative Physiol Ther, 1992;15(1):57-61

Abstract: This paper studies somatovisceral reflex responses in the cardiovascular organ, gastrointestinal tract, urinary bladder and adrenal medulla in anesthetized animals after eliminating emotional factors following somatic sensory stimulations. Various somatic sensory stimulations, including cutaneous, muscle and articular sensory stimulations, can produce differing autonomic reflex responses, depending on which visceral organs and somatic afferents are stimulated. Some responses have dominant sympathetic efferent involvement, whereas others have dominant parasympathetic efferent involvement. Some responses have propriospinal and segmental characteristics, while others have supraspinal and generalized characteristics in their reflex nature. These somatovisceral reflex responses may be functioning during spinal manipulative therapy in conscious humans.

Evaluation of neck muscle strength with a modified sphygmomanometer dynamometer: reliability and validity, Vernon HT, Aker P, Aramenko M, Battershill D, Alepin A, Penner T.

-- Canadian Memorial Chiropractic College, Toronto, Ontario.

J Manipulative Physiol Ther. 1992 Jul-Aug;15(6):343-9. 

OBJECTIVE: Determine test-retest reliability, normative data and clinical validity of isometric muscle strength testing in the neck with a modified sphygmomanometer dynamometer (MSD). DESIGN: Analytic survey. Paired trials of various muscle strength tests were conducted on convenience samples of normal subjects and consecutive samples of symptomatic subjects. SETTING: Outpatient chiropractic research clinic. PATIENTS/SUBJECTS: For study 2, 40 normal male subjects, average age 25 +/- 2 yr, were studied for reliability and normative data. For study 3, 24 symptomatic patients, 12 males and 12 females, average age 39 +/- 7 yr, were studied, 8 with "whiplash"-type injuries (average duration 22.5 wk) and 16 with nontraumatic chronic neck pain (average duration 110 wk). INTERVENTION: No therapeutic intervention is reported. MAIN OUTCOME MEASURE: Pressure levels generated by subjects against a modified sphygmomanometer-type dynamometer as measured in kilopascals. RESULTS: Study 1. Repeated paired trials of a standardized weight column (20 lbs) produced a coefficient of variation of 0.84% and virtually no difference between the means of the first vs. second trials. Study 2. High test-retest correlation coefficients were found for all ranges of motion (.79-.97). Right-to-left asymmetry in rotation and lateral flexion was within 6-8%. The flexion/extension ratio was .57:1, indicating that in normal subjects, flexion was approximately 40% lower than extension. Lower cutoffs were established as the mean--1 SD as follows (in kPa): flexion--3300, extension--5800, rotation--5200 and lateral flexion--6200. Coefficients of variation ranged from 25 to 29%. Study 3. Differences between paired trials were analyzed by intraclass coefficients, which were very high (.95-.99), and by percentages, which ranged from 4 to 10.4%, with an average of 7%, indicating a high degree of test-retest consistency. The mean values for all symptomatic subjects for flexion, extension, right rotation and right lateral bending were all well below the normal cutoff values as found in study 2. The flexion/extension ratio for whiplash subjects was 0.25:1.00, which is half of that of normal subjects. CONCLUSIONS: The MSD has been found to be a reliable instrument for the evaluation of isometric muscle strength in the neck in normal and symptomatic subjects. Normative values for absolute test levels, bilateral symmetry and flexion/extension ratios have been determined. A symptomatic group demonstrated significant deviations from these norms in the form of reduced strength levels and reduced flexion/extension ratios, while still maintaining very high levels of test-retest consistency and bilateral symmetry. The MSD appears very promising in the evaluation of neck-injured patients.

Effect of osteopathic medical management on neurologic development in children,
Frymann VM, Carney RE, Springall P.

J Am Osteopath Assoc. 1992 Jun;92(6):729-44.

Abstract: For 3 years, children between 18 months and 12 years of age with and without recognized neurologic deficits were studied at the Osteopathic Center for Children. Their response to 6 to 12 osteopathic manipulative treatments directed to all areas of impaired inherent physiologic motion was estimated from changes in three sensory and three motor areas of performance. Houle's Profile of Development was used to compare neurologic with chronologic age and rate of development, and scores were age-adjusted. Results in children after treatment were compared with those following a waiting period without treatment. Neurologic performance significantly improved after treatment in children with diagnosed neurologic problems and to a lesser degree in children with medical or structural diagnoses. The advances in neurologic development continued over a several months' interval. The results support the use of osteopathic manipulative treatment as part of pediatric healthcare based on osteopathic medical philosophy and principles.

Postural control in young and elderly adults when stance is perturbed: kinematics, Alexander, N. B, Shepard, N, Gu, MJ, Schultz, A. 

Journal of Gerontology, 1992; 47:M79-M87.

Abstract: Increased postural sway and falling are associated with aging and are likely related to problems with postural control in the elderly. We investigated the motions of individual body segments in 24 healthy young adults and 15 healthy elderly adults (mean ages 26 and 72) in response to four tasks: (a) standing with feet flat on an anteriorly accelerating platform (Flat Translation); standing on a narrow beam support that was (b) stationary (Beam Standing) and (c) accelerating anteriorly (Beam Translation); and (d) standing on a rotatable but otherwise stationary springboard (Springboard Standing). An optoelectronic camera system was used to measure rotations of body segments, particularly regarding their maximum excursions, time to first rotation response, direction of initial rotation, and time to first rotation reversal. In general, larger rotation excursions were noted in the elderly compared to the young group, particularly in the Beam Standing and Beam Translation tasks, but the magnitude of rotation difference was small. All rotation magnitudes were well within the available ranges of motion of the body joints. In both excursion magnitudes and directions of initial rotation, the elderly showed greater variability than the young. In the Beam Translation task, the elderly group, compared to the young, tended to rotate their upper body segments more than in the Flat Translation task. These data suggest that healthy elderly adults with no apparent musculoskeletal or neurological impairments have small but consistent differences in postural control kinematics, particularly when more challenging conditions are presented. Moreover, these data provide the basis for biomechanical analyses of joint torques and other dynamic requirements of these responses.

Comment: Manual muscle testing is the method of testing functional neurology and postural mechanisms in applied kinesiology. Normally there is predictable facilitation and inhibition of muscle function. When there is not, applied kinesiology testing methods are employed to discover and correct the factors responsible for the disturbance in predictable muscle function.  The importance of restoring normal function in elderly patients is demonstrated by the postural kinematic disturbances of the patients in this study.

The stabilizing system of the spine. Part I. Function, dysfunction, adaptation, and enhancement, Panjabi MM.

J Spinal Disord, 1992 Dec;5(4):383-9; discussion 397.

Abstract: Presented here is the conceptual basis for the assertion that the spinal stabilizing system consists of three subsystems. The vertebrae, discs, and ligaments constitute the passive subsystem. All muscles and tendons surrounding the spinal column that can apply forces to the spinal column constitute the active subsystem. The nerves and central nervous system comprise the neural subsystem, which determines the requirements for spinal stability by monitoring the various transducer signals, and directs the active subsystem to provide the needed stability. A dysfunction of a component of any one of the subsystems may lead to one or more of the following three possibilities: (a) an immediate response from other subsystems to successfully compensate, (b) a long-term adaptation response of one or more subsystems, and (c) an injury to one or more components of any subsystem. It is conceptualized that the first response results in normal function, the second results in normal function but with an altered spinal stabilizing system, and the third leads to overall system dysfunction, producing, for example, low back pain. In situations where additional loads or complex postures are anticipated, the neural control unit may alter the muscle recruitment strategy, with the temporary goal of enhancing the spine stability beyond the normal requirements.

Comment: This paper elegantly describes a number of the fundamental tenets of AK. Under normal conditions, structural balance is maintained by the muscles of the body (“the active subsystem”), that is controlled by the nervous system. With MMT, when a muscle tests as inhibited, treatment to the portion of the nervous system causing the inhibition restores the muscle to normal facilitation. Importantly, Dr. Panjabi suggests that changes in neural function produces immediate changes in muscle function. This correlation is at the center of the successes achieved using AK therapeutics.

The stabilizing system of the spine. Part II. Neutral zone and instability hypothesis, Panjabi MM

J Spinal Disord, 1992 Dec;5(4):390-6; discussion 397.

Abstract: The neutral zone is a region of intervertebral motion around the neutral posture where little resistance is offered by the passive spinal column. Several studies--in vitro cadaveric, in vivo animal, and mathematical simulations--have shown that the neutral zone is a parameter that correlates well with other parameters indicative of instability of the spinal system. It has been found to increase with injury, and possibly with degeneration, to decrease with muscle force increase across the spanned level, and also to decrease with instrumented spinal fixation. In most of these studies, the change in the neutral zone was found to be more sensitive than the change in the corresponding range of motion. The neutral zone appears to be a clinically important measure of spinal stability function. It may increase with injury to the spinal column or with weakness of the muscles, which in turn may result in spinal instability or a low-back problem. It may decrease, and may be brought within the physiological limits, by osteophyte formation, surgical fixation/fusion, and muscle strengthening. The spinal stabilizing system adjusts so that the neutral zone remains within certain physiological thresholds to avoid clinical instability.

Comment: Unless there is a bony deformity, muscle imbalance is basic to structural distortion and changes in the motion and positioning of the spinal joints. For distortions in the kinematics of the neutral zone or for spinal subluxations to be maintained, muscle imbalance must be present. Dr. Panjabi’s paper once again elucidates several fundamental tenets of AK.

Intrarater reliability of manual muscle test (Medical Research Council scale) grades in Duchenne's muscular dystrophy, Florence JM, Pandya S, King WM, Robison JD, Baty J, Miller JP, Schierbecker J,  Signore LC.

Phys Ther. 1992 Feb;72(2):115-22; discussion 122-6

Abstract: The purpose of this study was to document the intrarater reliability of manual muscle test (MMT) grades in assessing muscle strength in patients with Duchenne's muscular dystrophy (DMD). Subjects were 102 boys, aged 5 to 15 years, who were participating in a double-blind, multicenter trial to document the effects of prednisone on muscle strength in patients with DMD. Four physical therapists participated in the study. Two identical (duplicate) evaluations were performed within 5 days of each other by the same examiner initially and after 6 and 12 months of treatment. A total of 18 muscle groups were tested on each patient, 16 of them bilaterally, using a modification of the Medical Research Council scale. Reliability of muscle strength grades obtained for individual muscle groups and of individual muscle strength grades was analyzed using Cohen's weighted Kappa. The reliability of grades for individual muscle groups ranged from .65 to .93, with the proximal muscles having the higher reliability values. The reliability of individual muscle strength grades ranged from .80 to .99, with those in the gravity-eliminated range scoring the highest. We conclude the MMT grades are reliable for assessing muscle strength in boys with DMD when consecutive evaluations are performed by the same physical therapist.

Cervicogenic dysfunction in muscle contraction headache and migraine: a descriptive study, Vernon H, Steiman I, Hagino C.

J Manipulative Physiol Ther. 1992 Sep;15(7):418-29.

OBJECTIVE: The prevalence and nature of findings of cervicogenic dysfunction is explored in subjects with muscle contraction/tension-type (MCH) headache and common migraine without aura (CM). DESIGN: Descriptive survey. SETTING: Chiropractic outpatient research clinic. PATIENTS: Forty-seven (47) subjects, aged 18-55 with two categories of benign headache, were studied: MCH (tension-type) n = 19 (6 males, 13 females) and CM (without aura), n = 28 (3 males, 25 females). Subjects were recruited as part of an intervention trial and, thus, form a consecutive sample of patients. The present findings were elicited as part of the initial assessment. INTERVENTION: No therapeutic intervention is reported. MAIN OUTCOME MEASURES: Standardized headache history; plain film and dynamic spinal X rays; motion palpation; and pressure algometry. RESULTS: For CM, the most prevalent headache locations were frontal (81%) and occipital (78%). Neck pain and upper back pain accompanied headache in 90% and 41% of subjects, respectively. For MCH, the most prevalent headache locations were occipital (87%) and frontal (81%). Neck and upper back pain accompanied headache in 100% and 27%, respectively, of all subjects. For the total group, 77% of all subjects and 89% of females exhibited a marked reduction, absence or reversal of the normal cervical lordosis. Ninety-seven percent of all subjects exhibited, on dynamic X-ray studies, at least one significant abnormality of segmental mobility from C1 to C7, while 43% exhibited abnormalities at four or more segments. Segmental motion at C0-C1 was reduced in 90% of subjects in flexion and 70% of subjects in extension. On motion palpation, 84% of CM and MCH subjects were found to have at least two major fixations from C0 to C2. On pressure algometry, 92% of CM and 85% of MCH had at least one verifiable tender point (TP) in the upper cervical region. The most common locations for TPs were mid-cervical (C2-C3), lateral occipital and suboccipital. CONCLUSIONS: Both MCH and CM subjects demonstrate high occurrences of: a) occipital and neck pain during headaches; b) tender points in the upper cervical region; c) greatly reduced or absent cervical curve; and d) X-ray evidence of joint dysfunction in the upper and lower cervical spine. These findings support the premise that the neck plays an important, but largely ignored role in the manifestation of adult benign headaches. A case-control study should be conducted to confirm the greater prevalence of cervicogenic dysfunction in headache as compared to nonheadache subjects.

Quantitative cervical flexor strength in healthy subjects and in subjects with mechanical neck pain, Silverman JL, Rodriquez AA, Agre JC.

Arch Phys Med Rehabil. 1991 Aug;72(9):679-81.

Abstract: Although weakness of anterior cervical muscles is postulated to contribute to persistent neck pain in patients with mechanical neck pain, quantitation of weakness has never been reported. We compared anterior cervical muscle strength in 30 subjects with mechanical neck pain and in 30 asymptomatic control subjects. Testing was performed with the subject supine, chin retracted, and neck flexed. Assessment was made using a hand-held dynamometer with head held at the midline and with rotation left and right within a pain-free range. Analysis with Wilcoxon scores showed that patients with neck pain had significantly less (p less than .05) strength (N.Kg-1) in all three positions than controls (1.16 +/- 0.49 vs. 1.71 +/- 0.42, sagittally; 1.01 +/- 0.52 vs. 1.47 +/- 0.41, rotation left; .99 +/- 0.46 vs. 1.43 +/- 0.43 rotation right; neck pain vs. control, respectively.) This weakness and its role in persistent neck pain should be recognized. The efficiency and effect of cervical muscle strengthening in treatment of chronic neck pain should be further defined.

Comment: This paper gives evidence for one of the fundamental tenets of AK and is very important. AK theorizes that physical imbalances are associated with secondary muscle dysfunction – specifically a muscle inhibition -- usually preceding an overfacilitation of an opposing muscle. Applying the proper therapy results in improvement in the inhibited muscle.

Reliability of testing measures in Duchenne or Becker muscular dystrophy, Barr AE, Diamond BE,

Wade CK, Harashima T, Pecorella WA, Potts CC, Rosenthal H, Fleiss JL, McMahon DJ.

Arch Phys Med Rehabil. 1991 Apr;72(5):315-9.

Abstract: In a multiinstitutional collaborative study, we ascertained the interevaluator and intraevaluator reliability of six physical therapists who performed assessment measures on 36 boys (11.7 +/- 3.9 years) with Duchenne or Becker muscular dystrophy. Upper and lower extremities were evaluated by manual muscle testing for function, range of motion, and strength. The data were analyzed using intraclass correlation coefficients (ICCs). For the interevaluator phase, ICCs were as follows: average muscle strength, .90; range of motion, .76; and upper extremity functional performance, .58. For the intraevaluator phase, corresponding ICCs were .80 to .96; .33 to .97; .34 to 1.00. Our results confirm and extend observations by others that these assessment measures are sufficiently reliable for use in a multiinstitutional collaborative effort. Such results can be used to design clinical trials that have sufficient statistical power to detect changes in the rate of disease progression. Investigators planning clinical trials in a multiinstitutional collaborative setting should first standardize the assessment methods, provide evaluator training, and document reliability.

Effects of restrained cervical mobility on voluntary eye movements and postural control, Karlberg M, Magnusson M, Johansson R.

Acta Otolaryngol, 1991;111(4):664-70.

Abstract: The effects of restrained cervical mobility on pursuit eye movements (PEMS), voluntary saccades and postural control, as measured by posturography, were studied in 11 healthy subjects whose cervical spine movement had been restrained for 5 days by means of a rigid neck-collar. At day 5 mean peak velocity of voluntary saccades at amplitudes of 40 degrees and 60 degrees was significantly reduced, as was mean peak gain of PEMs at a stimulus velocity of 50 degrees/s; the variance of body position in vibration-induced body sway was significantly increased, but there was no difference in variance of galvanically-induced body sway or in velocity of vibration-induced body sway. The results suggest that restriction of cervical movements per se affects voluntary eye movements, a conclusion also consistent with findings in patients with tension headache. Restriction of cervical movement only marginally affects postural control.

Comment: In applied kinesiology chiropractic methodology, a means for testing the integration of the muscles in the body with the visual reflexes has been termed ocular lock.It demonstrates the failure of the eyes to work together on a binocular basis through the cardinal fields of gaze.  When the eyes are turned in a specific direction, a previously strong indicator muscle will weaken when the ocular lock test is positive, and there is probably disturbance in the visual righting, vestibulo-ocular, or opto-kinetic reflexes.  The eyes must work together as a team so that each eye is directed to the same fixation point on a page, somewhat like two spotlights highlighting a dancer at the center of the stage.  This is called convergence. The focus of the eyes must also be quickly adjusted from one distance or angle to another, called accommodation.  The eyes must be able to track or scan along the horizon or a line of print smoothly and evenly so that the brain can receive a flow of sequentially correct visual information.  This is called tracking.  Eye motion and position are integrated with proprioceptors throughout the body, as well as those of the vestibular apparatus and head-on-neck reflexes. This is usually not gross pathology of cranial nerves III, IV, and VI; rather it is poor functional organization. Mechanical irritation of cranial nerves III, IV, or VI (usually VI) may be responsible for disturbed binocular function leading to discordant sensory inputs from the visual righting reflex. This paper shows that erroneous cervical spine sensory information converges in the central nervous system with the visual system, and this could affect the perception of body orientation and lead to a misinterpretation of relation to the surrounding.

Forefoot pain associated with muscle strain in the lower extremity, Hsieh CY.

J Manipulative Physiol Ther. 1991 Nov-Dec;14(9):527-9.

Abstract: A case of forefoot pain at the first metatarsophalangeal joint is discussed. Local treatment with ultrasound failed to bring significant relief. However, dramatic and lasting relief occurred when treatment was applied to the muscle belly of the extensor hallucis longus. The patient also suffered from hallux valgus with mild foot pronation. Two years after therapy, the patient stated she had not experienced any foot pain since the last treatment, and she continued to wear the prescribed flexible foot orthotics on a daily basis.

The pain-adaptation model: a discussion of the relationship between chronic musculoskeletal pain and motor activity, Lund, J.P., et al. 

Canadian Journal of Physiology and Pharmacology, 1991;69:683-694.

Abstract: Articles describing motor function in five chronic musculoskeletal pain conditions (temporomandibular disorders, muscle tension headache, fibromyalgia, chronic lower back pain, and postexercise muscle soreness) were reviewed. It was concluded that the data do not support the commonly held view that the pain of these conditions is maintained by some form of tonic muscular hyperactivity. Instead, it seems clear that in these conditions the activity of agonist muscles is often reduced by pain, even when this does not arise from the muscle itself. On the other hand, pain causes small increases in the level of activity of the antagonist. As a consequence of these changes, force production and the range and velocity of movement of the affected body part are often reduced. To explain how such changes in the behavior come about, we propose a neurophysiological model based on the phasic modulation of excitatory and inhibitory interneurons supplied by high-threshold sensory afferents. We suggest that the "dysfunction" that is characteristic of several types of chronic musculoskeletal pain is a normal protective adaptation and is not a cause of pain.

Comment: This paper articulates with fascinating similarity one of the major hypotheses in AK, namely that physical, chemical, or emotional imbalances produce secondary muscle dysfunction, specifically a muscle inhibition (usually followed by overfacilitation of an opposing muscle). Muscles lose function and become inhibited because of structural problems like trauma or chemical imbalance due to a hormonal influence or mental/emotional stress.

Musculoskeletal ontogeny, phylogeny, and functional adaptation, Carter DR, Wong M, Orr TE.

J Biomech. 1991;24 Suppl 1:3-16.

Abstract: Physical forces applied to connective tissues may cause significant changes in cell metabolism and gene expression. Theoretical investigations indicate that mechanical loading histories beginning very early in skeletal development may guide endochondral ossification patterns and the initial architectural construction of bones. Developmental patterns and structures of bones can be emulated using mathematical algorithms or "rules of construction" which relate developmental processes to tissue stress (or strain) histories. Skeletal forms and tissues are well-designed for their mechanical function primarily because their histomorphological construction has been guided by mechanical loading during growth and development. Construction rules of developmental mechanics can also be used to describe many of the histological and morphological adaptations of mature skeletal tissues to changes in customary physical activity. Over many generations, changes in the heritable genetic information occurs by mutation and genetic variability. The range of skeletal forms that are possible in evolution due to such variations, however, is constrained by the developmental rules of construction that reflect biophysical processes associated with the tissue mechanical loading.

Comment: This study shows how the intraosseous distortions of skeletal bones occur. These are found in AK to affect the spine, the cranium, and the extremities. Specific means of testing for abnormal intraosseous distortions have been developed in AK for treatment.

Effects of Soft Tissue Technique and Chapman's Neurolymphatic Reflex Stimulation on Respiratory Function, Lines, D., McMillan, A., Spehr, G.

J Aust Chiro Assoc 1990 Mar;20(1):17-22.

Limb Segment Information Transmission Capacity Infers Integrity of Spinothalamic Tracts and Cortical Visual-Motor Control, Leisman, G., Vitori, R.

International Journal of Neuroscience. 1990; 50:175-183.

Abstract: Limb segment movement times have been investigated previously in relation to Fitts’ Index of Difficulty (ID = log₂2A/W) over various movement distances. Results supported Fitts’ theory that different limb segments show different maximum information processing rates. The results indicated that visually-mediated discrete correction control processes are used. In the presently reported experiments, normal human subjects performed movements with left or right arms. Visual-motor control was inter- or intrahemispheric. Direction of movement was adductive or abductive. It was hypothesized that abductive movements are controlled by the contralateral hemisphere while adductive movements are controlled by either hemisphere. It was also hypothesized that abductive movements are related to the lateral system which projects to the contralateral side of the spinal cord. The control of adductive movements is related to the medial system which projects bilaterally to the spinal cord.

Spinal learning: central modulation of pain processing and long-term alteration of interneuronal excitability as a result of nociceptive peripheral input, Slosberg M.

J Manipulative Physiol Ther. 1990 Jul-Aug;13(6):326-36

Abstract: The influence of nociceptive peripheral input on the response characteristics of spinal interneurons may result in long-term alterations of interneuronal excitability and modify their responses to subsequent stimuli. Such neuromodulation has been found to result in physiological changes including hyperalgesia, lowering of pain thresholds, expansion of receptive fields and changes in response behaviors of muscles. These types of alterations may contribute to clinically significant findings including muscle spasm, hypomobility, edema, chronic pain, recurrences in areas of previous injury and resistance to treatment. This article reviews studies concerning plasticity of response behaviors of interneurons including habituation, spinal learning, spinal fixation, neuromodulation and the effects of substance P. Potential clinical and chiropractic application are discussed and a brief review of clinically relevant studies of chiropractic adjustments are cited.

Comment: This paper provides biological plausibility to the hypothesis of  the AK “challenge method.” Challenge tests are maneuvers performed by the examiner for stimulating subtle muscular changes in the body via mechanoreceptors in muscles, meninges, diarthrodial joints, ligaments or tendons, associated with the spine, cranial sacral mechanism, or extraspinal articulations.

Interactions between non-symmetric mechanical vector forces in the body and the autonomic nervous system: basic requirements for any mechanical technique to engender long-term improvements in autonomic function as well as in the functional efficiency of the respiratory, cardiovascular, and brain systems, Kullok S, Mayer C, Backon J, Kullok J.

Med Hypotheses. 1990 Jul;32(3):173-80.

Abstract: There are known anatomical asymmetries in the respiratory, cardiovascular, and nervous system. The coupling mechanisms between each of these systems--lungs-heart, heart-brain, and lungs-brain--are also asymmetrical. There is a growing body of literature indicating that mechanical pressure asymmetrically applied to certain areas of the human body produces changes in the balance of autonomic parameters. These findings implicitly indicate that not only magnitude but also the direction and point of application of the force play a role in its influence upon the autonomic nervous system. Therefore, we suggest that asymmetrical vector forces resulting from the mechanical activity of the lungs, heart and blood moving throughout the circulatory system, will also produce a lateralization effect in autonomic balance. We postulate the existence of negative feedback loops between brain autonomic control and mechanical functions in the body as a fundamental part of the body's homeostatic mechanisms. It follows that any mechanical assist to the respiratory or cardiovascular system will be significantly reduced or even eliminated if these homeostatic mechanisms are not taken into account. Our hypothesis predicts that a long-term improvement in autonomic balance as well as in respiratory, cardiovascular, and brain function can be achieved if mechanical forces are applied to the body with the aim of reducing existing imbalances of mechanical force vectors. This technique implies continually controlling for precise timings resulting from physiological periodical forces as well as factors derived from anatomical and coupling asymmetries in the respiratory, cardiovascular, and nervous systems.

Shoulder pain and repetition strain injury to the supraspinatus muscle: etiology and manipulative treatment, Jacobson EC, Lockwood MD, Hoefner VC Jr, Dickey JL, Kuchera WL.

J Am Osteopath Assoc. 1989 Aug;89(8):1037-40, 1043-5.

Abstract: Chronic inflammation and degenerative tendonitis of the supraspinatus muscle is an important cause of intrinsic shoulder pain. Injury to this muscle is usually caused, not by a single event, but by slight to moderate trauma repeatedly to the same anatomic area. The term repetition strain injury is used to describe this form of microtrauma. Repetition strain injury of the supraspinatus muscle is not an isolated event, but rather a form of microtrauma that affects the entire shoulder girdle. This functional unit must be evaluated and considered in the treatment plan. The authors discuss the diagnosis of this pain syndrome, which is based on the patient's work history, motion and strength testing, and palpation for trigger points. They also provide instruction in treatment involving manipulation with functional and counterstrain techniques combined with home exercise and modification of work posture.

Stability of the lumbar spine. A study in mechanical engineering, Bergmark A.

Acta Orthop Scand Suppl. 1989;230:1-54.

Abstract: From the mechanical point of view the spinal system is highly complex, containing a multitude of components, passive and active. In fact, even if the active components (the muscles) were exchanged by passive springs, the total number of elements considerably exceeds the minimum needed to maintain static equilibrium. In other words, the system is statically highly indeterminate. The particular role of the active components at static equilibrium is to enable a virtually arbitrary choice of posture, independent of the distribution and magnitude of the outer load albeit within physiological limits. Simultaneously this implies that ordinary procedures known from the analysis of mechanical systems with passive components cannot be applied. Hence the distribution of the forces over the different elements is not uniquely determined. Consequently nervous control of the force distribution over the muscles is needed, but little is known about how this achieved. This lack of knowledge implies great difficulties at numerical simulation of equilibrium states of the spinal system. These difficulties remain even if considerable reductions are made, such as the assumption that the thoracic cage behaves like a rigid body. A particularly useful point of view about the main principles of the force distributions appears to be the distinction between a local and a global system of muscles engaged in the equilibrium of the lumbar spine. The local system consists of muscles with insertion or origin (or both) at lumbar vertebrae, whereas the global system consists of muscles with origin on the pelvis and insertions on the thoracic cage. Given the posture of the lumbar spine, the force distribution over the local system appears to be essentially independent of the outer load of the body (though the force magnitudes are, of course, dependent on the magnitude of this load). Instead different distributions of the outer load on the body are met by different distributions of the forces in the global system. Thus, roughly speaking, the global system appears to take care of different distributions of outer forces on the body, whereas the local system performs an action, which is essentially locally determined (i.e. by the posture of the lumbar spine). The present work focuses on the upright standing posture with different degree of lumbar lordosis. The outer load is assumed to consist of weights carried on the shoulders. By reduction of the number of unknown forces, which is done by using a few different principles, a unique determination of the total force distributions at static equilibrium is obtained.

Reliability of quantitative muscle testing in healthy children and in children with Duchenne muscular dystrophy using a hand-held dynamometer, Stuberg WA, Metcalf WK.

Phys Ther. 1988 Jun;68(6):977-82.

Abstract: The purpose of this study was to examine intratester and test-retest reliability using a hand-held dynamometer for the measurement of isometric muscle strength in 28 healthy children and children with Duchenne muscular dystrophy. The Dystrophic Group consisted of 14 children diagnosed with Duchenne muscular dystrophy, and the Healthy Group consisted of 14 age-matched children with no history of orthopedic or neuromuscular disorders. One physical therapist tested hip and knee extension, elbow flexion, and shoulder abduction in each child bilaterally. A two-way analysis of variance for repeated measures was used to analyze differences between measurements taken within and across the testing sessions. Pearson product-moment correlation coefficients were determined on mean values across the testing sessions for each variable. No significant differences (p greater than .05) between measurements taken within or across testing sessions were found in either the Dystrophic Group or the Healthy Group. Correlation coefficients for the Dystrophic Group ranged from .83 to .99 for the variables tested. Correlation coefficients for the Healthy Group ranged from .74 to .99. The results suggest that the hand-held dynamometer can be used as a reliable instrument in measuring the isometric strength of selected muscles in children.

Influence of different static head-body positions on spinal lumbar interneurons in man: the role of the vestibular system, Rossi A, Mazzocchio R.

ORL J Otorhinolaryngol Relat Spec, 1988;50(2):119-26.

Abstract: The present experiments were made in man with the aim of studying the possible influences of different head-body tilts on the activity of the interneurons Ia, Ib and the Renshaw cells functionally coupled to the soleus alpha-motoneurons. Subjects were seated on a chair, rotable with respect to the vertical axis, and were studied at 80 degrees and 40 degrees to the horizontal. The excitability of the soleus alpha-motoneurons slightly decreased when the body was placed at 40 degrees of backward inclination whereas the Renshaw cell activity showed a reinforcement of inhibition on the same motoneurons. The reciprocal inhibition from the anterior tibial to the soleus muscle increased at 40 degrees of backward inclination with respect to the control values at 80 degrees. Finally, short-latency homonymous facilitation and inhibition showed no significant change in relation to body position. The results indicate that different head-body positions are able to modify the bias of spinal interneurons in man. We discuss the hypothetical role of the vestibular system in producing the effects seen.

Comment: The labyrinthine and visual righting reflexes may be disturbed by joint or muscle problems in the neck, as well as by cranial faults that may result from either whiplash dynamics or a blow to the head during an automobile accident or other head and neck trauma. It is hypothesized in AK that temporal bone cranial faults can result in imbalance in one or both sternocleidomastoid and upper trapezius muscles due to mechanical irritation of cranial nerve XI as it exits the skull through the jugular foramina, and could thereby disturb the biomechanics of the joints in the neck. This phenomenon is found on a daily basis in the clinical setting, and muscles anywhere in the body may be facilitated by proper cranial therapy. Anatomical distortions of the geometry of the vestibular mechanism within the temporal bones (producing a tilt in the angular geometry of the semicircular canals) may create discordant sensory input into the CNS compared to that coming into it from the spinal joints and muscles, thereby producing poor stability and deficient motor activity.

Effects of altered afferent articular input on sensation, proprioception, muscle tone and sympathetic reflex responses, Slosberg M.

J Manipulative Physiol Ther. 1988 Oct;11(5):400-8.

Abstract: The influence of afferent articular and periarticular input on muscle tone, joint mobility, proprioception and pain is of considerable interest to practitioners using manipulation. It has long been hypothesized that dysfunctional articulations may generate altered patterns of afferent input. This article reviews the relevant studies that have investigated the impact of articular input on efferent activity under normal conditions and under conditions of altered joint function. The findings suggest that sensory input does have a substantial effect on efferent function and sensation. Furthermore, the studies indicate that the pattern of articular input may be significantly modified by joint inflammation, trauma and effusion and result in changes of muscle tone, joint mobility, proprioception and pain.

Comment: This paper provides biological plausibility to the hypothesis of  the AK “challenge method.” Challenge tests are maneuvers performed by the examiner for stimulating subtle muscular changes in the body via mechanoreceptors in muscles, meninges, diarthrodial joints, ligaments or tendons, associated with the spine, cranial sacral mechanism, or extraspinal articulations.

Comparison of lumbar paravertebral EMG patterns in chronic low back pain patients and non-patient controls,
Ahern DK, Follick MJ, Council JR, Laser-Wolston N, Litchman H.

Pain. 1988 Aug;34(2):153-60.

Abstract: According to myogenic models that relate abnormal EMG patterns to the experience of pain, lumbar paravertebral muscle activity has been considered to play an important role in chronic low back pain. In the present study, 40 chronic low back pain patients and 40 matched non-patient controls were compared on lumbar paravertebral EMG during mechanically stabilized static and dynamic postures. Differences between groups in lumbar curvature and spinal range of motion were determined using a dual goniometer technique. Although the two groups did not differ on absolute levels of EMG during quiet standing, significant differences were found for EMG patterns during dynamic postures. In addition, most patients did not show the flexion-relaxation response or the expected pattern of EMG responses during trunk rotation, most likely because of restricted range of motion and/or compensatory posturing. These findings provide support for the biomechanical model of chronic pain and indicate the need for further research pertaining to pain behavior and movement-related lumbar muscle activity.

Intrarater reliability of manual muscle testing and hand-held dynametric muscle testing, Wadsworth CT, Krishnan R, Sear M, Harrold J, Nielsen DH.

Phys Ther. 1987 Sep;67(9):1342-7. 

Physical therapists require an accurate, reliable method for measuring muscle strength. They often use manual muscle testing or hand-held dynametric muscle testing (DMT), but few studies document the reliability of MMT or compare the reliability of the two types of testing. We designed this study to determine the intrarater reliability of MMT and DMT. A physical therapist performed manual and dynametric strength tests of the same five muscle groups on 11 patients and then repeated the tests two days later. The correlation coefficients were high and significantly different from zero for four muscle groups tested dynametrically and for two muscle groups tested manually. The test-retest reliability coefficients for two muscle groups tested manually could not be calculated because the values between subjects were identical. We concluded that both MMT and DMT are reliable testing methods, given the conditions described in this study. Both testing methods have specific applications and limitations, which we discuss.

Changes in Electrical Activity in Muscles Resulting from Chiropractic Adjustment: A Pilot Study, Shambaugh P.

J Manipulative Physiol Ther 1987;10(6):300-304.

This study examines the effects of chiropractic adjustment on the muscles of the back. Vertebrae that are hypomobile may be held in that state by the erector spinae muscle group; adjusting such vertebrae should result in less muscle tension. By measuring the change in electrical activity, such relaxation can be observed. Hypomobile vertebrae were found by motion palpation. The patient was then placed prone and surface electrodes were placed over the upper trapezius, upper erector spinae (T3-T5), and lumbar erector spinae (L1-L3) muscle groups on both sides of the body. The patient was adjusted using full spine toggle recoil thrusts, and postadjustment readings were taken. Results from this study show that significant changes in muscle electrical activity occur as a consequence of adjusting. On average, a 25% reduction in muscle activity was observed across the 20 subjects tested, while no significant reductions were observed with the control group of 14 subjects. Significant reductions in side-to-side imbalances were also observed.

Effects of joint pathology on muscle, Young A, Stokes M, Iles JF.

Clin Orthop Relat Res, 1987 Jun;(219):21-7.

Abstract: The muscle wasting associated with joint damage may be highly selective; knee disorders produce quadriceps wasting but little change in the size of the hamstrings. This causes isolated quadriceps weakness, so predisposing to a position of knee flexion. Nociceptors and other receptors in and around the joint can have flexor excitatory and extensor inhibitory actions. At the knee, these receptors are likely to excite hamstrings and inhibit quadriceps. Although other actions could occur, quadriceps inhibition may be favored by a position of knee extension. Quadriceps inhibition will weaken voluntary contraction, reduce tone, and contribute to wasting of the muscle, further predisposing to a position of knee flexion. The potency of quadriceps inhibition may be considerable, even in the absence of perceived pain. A small, apparently trivial effusion (or even a clinically undetectable effusion) may cause important inhibition. In order to improve the orthopedist's ability to prevent flexion contracture of the injured or operated joint, he must look not only for ways of reducing joint pain, but also for ways of preventing activity in other joint afferents. For example, he must consider the possible effects of joint position, intraarticular pressure, suture-line tension, and afferent blockade.

Comment: This study demonstrates that structural alterations in the knee joints produce immediate and measurable weaknesses in the muscles that support and stabilize the knee. If the muscles at the front of the knee (quadriceps) are weak, this may produce joint instability and perpetuate the knee joint dysfunction until corrected.

Quantifying the Effects of Spinal Manipulations on Gait, Using Patients with Low Back Pain: A Pilot Study, Herzog W, Nigg B, Robinson R, Read L.

J Manipulative Physiol Ther 1987;10(6):295-299

A pilot study was performed to investigate the effects of chiropractic treatment on the gait of one patient with a chronic sacroiliac joint syndrome. Qualitative and quantitative measures were used to describe pain, sacroiliac joint mobility, functional ability and gait patterns of this patient before and after receiving chiropractic treatment, and throughout the rehabilitation period. For this patient, chiropractic treatment reduced the low back pain and was associated with significant changes in selected gait parameters. A study involving 10-20 subjects is under way to possibly generalize the findings of this investigation.

Finger flexion function in rheumatoid arthritis: the reliability of eight simple tests, Armstrong R, Horrocks A, Rickman S, Heinrich I, Kay A, Gibson T.

Br J Rheumatol 1987;26:118-122.

The inter- and intra-observer errors of eight tests of finger flexion function were estimated from the results obtained by three observers assessing 10 patients with rheumatoid hand involvement. Measurements of finger flexion and muscle power involved both conventional and novel techniques using simple and easily constructed apparatus. For each test, measurements were in agreement between observers and were reproducible on three occasions. These tests may now be used with confidence by other investigators.

Functional assessment of the hand: reproducibility, acceptability, and utility of a new system for measuring strength, Helliwell P, Howe A, Wright V.

Ann Rheum Dis 1987;46:203-208

A new system for measuring strength of the hand using a torsion dynamometer linked to a microprocessor is described. The system permits analysis of timed squeezes of both grip and pinch and is adjustable to all sizes of hand and degrees of hand deformity. Results obtained with the system were found to be reproducible, and the rigid device was acceptable to a group of patients with arthritic hands. In rheumatoid arthritis, there is a marked reduction in maximum grip and pinch strength, together with a prolongation of the time taken to reach this maximum, and increased fatigue. The limitations of grip strength as a measure of function of the hand are discussed.

Clinical and electromyographical course of sciatica: prognostic study of 41 cases, Negrin P, Fardin P.

Electromyogr Clin Neurophysiol 1987;27:125-127

Abstract: The study of the clinical and EMGraphical course of patients with sciatica may help us to decide between a simple symptomatic treatment and an admission to hospital for neuroradiological tests and possible surgery. 41 patients with acute lumbosciatalgia and EMGraphically proven monoradicular denervation were studied: the root affected was L5 in 39 cases (78%), L4 in 7 cases and S1 in 2 cases. 19 of these cases were then submitted to surgical treatment of disc protrusion removal, the other 22 were treated medically. 3 to 8 years later, the following parameters were tested: pain, motor impairment, EMG denervation and degree of patient’s subjective judgment. We concluded that urgent hospital admission is indicated only in the case of severe and/or recent (within 1 month) paralysis or in the case of intolerable painful symptomatology. The diagnostic and prognostic role of EMG is hence confirmed: this examination yields information on the identity of the root involved, the severity of the denervation, its course and the degree of final improvement expected.

The use of major and minor therapy forms in
Australian chiropractic practice, Leboeuf, C, Patrick, K.

Journal of the Australian Chiropractic Association, 1987;17:109-11.

A survey of Australian chiropractors showed that most use five major
chiropractic techniques (Diversified, Sacro-Occipital technique, Gonstead,
Nimmo and Applied Kinesiology). High velocity adjustive techniques
(Diversified and Gonstead) were the most commonly reported major core
techniques. Predominantly low velocity manual techniques such as Applied
Kinesiology, Sacro-Occipital technique and Nimmo were most commonly reported as minor core techniques. Most employ adjunctive therapies, mainly nutrition, extremity techniques and exercise.

The relationship of knee and ankle weakness to falls in nursing home residents, Whipple, R, Wolfson, L, Amerman, P.

J Am Geriatr Soc, 1987;35:329-32

A study of nursing home residents with a history of falling found that muscle force and isokinetic power were significantly decreased in knee flexors (quadriceps) and extensors (hamstrings), and ankle dorsiflexors (tibialis anterior) and plantar flexors (gastrocnemius and soleus). Dorsiflexors were particularly weak in fallers, suggesting that they are an important factor contributing to balance. Of particular interest was ankle flexor and extensor strength because these muscles are linked to balance impairment in older adults with a history of falling. Strength training and other treatments that may improve muscle function in these areas may enhance balance in balance-impaired older adults.

Piriformis syndrome: pathogenesis, diagnosis, and treatment, Steiner C, Staubs C, Ganon M, Buhlinger C.

J Am Osteopath Assoc 1987;87:318-323

The failure of conservative treatment for lumbosacral disk disorders often leads to surgery. If the pain is produced by sciatic neuritis rather than sciatic radiculitis, operative treatment may be unavailing. This paper describes the mechanism by which piriformis syndrome causes sciatic neuritis and differentiates neuritis from radiculitis, the treatment of which often results in the “failed disk syndrome.” Sciatic neuritis is now believed to result from irritation of the sciatic nerve sheath, which is caused by biochemical agents released from an inflamed piriformis muscle where the two structures meet at the greater sciatic foramen. The symptoms of piriformis syndrome present almost identically to lumbar disk syndrome, except for the consistent absence of true neurologic findings. Diagnosis is accomplished by palpation of myofascial trigger points within the piriformis muscle. Computed tomography, myelography, roentgenography, and electromyography are of limited diagnostic value. Treatment, which consists of a conservative approach employing local anesthetics and osteopathic manipulation, is without significant risk. Reducing muscle spasm, restoring joint motion, and keeping the patient ambulatory and in motion are keys to successful treatment.

Correlation of objective measure of trunk motion and muscle function with low-back disability ratings, Triano, J, Schultz, A

Spine, 1987;12:561-5.

Abstract: A study was undertaken to examine relations among some objective and subjective measures of low-back-related disability in a group of 41 low-back pain patients and in seven pain-free control subjects. Subjective measures of disability were obtained by Oswestry patient questionnaires. Oswestry disability score related significantly (P less than 0.001) to presence or absence of relaxation in back muscles during flexion. Mean trunk strength ratios were inversely related to disability score (P less than .05), and trunk mobility was meaningfully reduced (P less than .01). Despite loss of motion, a large enough excursion was observed to predict presence of back muscle relaxation. These findings imply that myoelectric signal levels, trunk strength ratios, and ranges of trunk motion may be used as objective indicators of low-back pain disability.

Comment: The findings in this study imply that muscle function, as measured by EMG, MMT, and ranges of trunk motion may be used as objective indicators of low-back pain disability.

Clinical biomechanical correlates for cervical function: Part II. A myoelectric study, Vorro J, Johnston W.

J Am Osteopath Assoc 1987;87:353-367

Part 1 of this study compared cervical motion ranges for two groups of human subjects classified as symmetric or asymmetric on the basis of a single clinical test for cervical sidebending. Data from the asymmetric group revealed limited mobility in all primary rotations and in secondary deviations. Part 2 reports on the concurrent, bilateral measurement of electromyographic activity for 12 selected muscle sites during the movements executed. Data revealed that muscles in the asymmetric group were slower to initiate action and were reduced in time and strength of contraction. Because muscles provide the motive forces for the reduction in range previously reported, these myoelectric data expand understanding of the disturbance in physiologic function that is indicated when a clinical test for response to motion in a spinal region is positive for asymmetry.

The relationship of injuries of the leg, foot, and ankle to proximal thigh strength in athletes, Nicholas JA, Marino M.

Foot Ankle. 1987 Feb;7(4):218-28

Abstract: Rehabilitation programs designed to restore leg, ankle, and foot function following injury frequently ignore the proximal muscles. During athletics, these knee, hip, and trunk muscles derive much of their functional power from the foot and ankle. They also serve to integrate distal segment motions into a total movement pattern such as jumping, running, or kicking. The linkage system, which is a theoretical concept, describes the normal biomechanical and physiological interactions between proximal and distal musculoskeletal structures. Immobilization or injury of distal segments interrupts the normal generation, summation, and transmission of muscular forces across joints. Adequate measures must be taken to properly assess proximal structures for weakness and tightness and to prescribe specific exercises to prevent the migration of the effects of injury away from the involved segment.

Comment: In AK examination and treatment, the “linkage system” is appreciated. The leg, foot, and ankle are part of a complex system that links the foot and leg and their related muscle attachments and other soft tissues, and neurologic and vascular components, to the rest of the neuromusculoskeletal system The use of AK methods, especially challenge and therapy localization, greatly assists the practitioner in finding concealed or hidden linkages between problems in the foot and leg and other muscular problems throughout the body.

The craniocervical junction and disturbance of equilibrium, Lewit K.

Manuelle Medizine. 1986;24:26-9

Abstract: A random group of 106 patients affected by pain due to functional disturbances in the spinal column with no symptoms of vertigo were examined using the two-scales test and Hautant’s test in various head and neck positions. The sample was divided into two groups: one had a difference of more than 4 kg on both scales, and one a difference of up to 4 kg. It was shown that: (1) all patients with a difference of more than 4 kg showed a cervical pattern when examined by the (modified) Hautant’s test and in patients with a difference below 4 kg this was found in only 5 cases; (2) a cervical pattern therefore existed in 55 (52%) of a random group with vertebrogenic disturbances; (3) the greatest difference in both groups was in the incidence of movement restriction in the craniocervical junction. This was absent in the first group in only 5 patients, and in 35 in the second. The cervical pattern was closely correlated with nystagmus in the extreme position when examined using Frenzel’s spectacles. Immediately after treatment, the cervical pattern (Hautant’s test) was usually normalized; frequently (in about half the cases) we obtained normal results on both scales; nystagmus in the extreme position examined with Frenzel’s spectacles usually remained positive. The dominating influence of the craniocervical junction for human equilibrium is stressed; disturbance of the equilibrium is much more frequent without vertigo (dizziness) than with. The term “latent vertigo” is suggested for the former. In this disturbance the motor system plays a decisive role. Equilibrium can therefore be defined as a function of the motor system subserving posture in the field of gravity.

Contractile changes in opposing muscles of the human ankle join with aging, Vandervoort, A, McComas, A.

J Appl Physiol, 1986;61:361-7

This article demonstrates that strength declines approximately 15% per decade between the ages of 50 and 70 years, and approximately 1.5% per year after the age of 70 years, and decreases in strength are associated with falling in elderly people.

Manual muscle test scores and dynamometer test scores of knee extension strength, Bohannon RW.

Arch Phys Med Rehabil. 1986 Jun;67(6):390-2. 

The knee extension force of 50 patients was investigated using traditional manual muscle testing and hand-held dynamometry. The relationship between manual muscle test word scores and dynamometer force scores was determined using Kendall tau, as was the relationship between manual muscle test percentage scores and dynamometer scores expressed as a percentage of "normal." Percentage scores were also compared to determine if a significant difference existed. Manual muscle test scores and dynamometer test scores were significantly correlated (p less than .001). Percentage manual muscle test and dynamometer test scores were significantly different (p less than .001). These results suggest that the two procedures measure the same variable-strength. Manual muscle test percentage scores of knee extension may, however, overestimate the extent to which a patient is "normal."

Predictive value of manual muscle testing and gait analysis in normal ankles by dynamic electromyography, Perry, J.P. et al

Foot Ankle. 1986 Apr;6(5):254-9.

Eight muscles about the ankle of seven normal subjects were assessed by electromyography (EMG) during manual muscle testing (MMT) and walking. Three strength levels (normal, fair, trace) and three gait velocities (free, fast, slow) were tested. The muscles studied included the gastrocnemius, soleus, posterior tibialis, flexor digitorum longus, flexor hallucis longus, anterior tibialis, extensor digitorum longus, and extensor hallucis longus. Relative intensity of muscle action was quantitated visually (using an eight-point scale based on amplitude and density of the signal). The data showed that EMG activity increased directly as more muscle force was required during the different manual muscle test levels and increased walking speeds. No MMT isolated activity to the specific muscle though being tested. Instead, there always was a synergistic response. Both the gastrocnemius and soleus contributed significantly to plantarflexion regardless of knee position. The intensity of muscle action during walking related to the manual muscle test grades. Walking at the normal free velocity (meters/min) required fair (grade 3) muscle action. During slow gait the muscle functioned at a poor (grade 2) level. Fast walking necessitated muscle action midway between fair and normal, which was interpreted as good (grade 4).

Reliability of lumbar paravertebral EMG assessment in chronic low back pain, Ahern DK, Follick MJ, Council JR, Laser-Wolston N.

Arch Phys Med Rehabil. 1986 Oct;67(10):762-5.

Abstract: The reliability of lumbar paravertebral EMG assessment was investigated in a sample of 70 patients with chronic low back pain, (CLBP). Dual-site EMG monitoring was employed during both static postures and movements. Flexion and rotation indices were divided to assess the reliability of patterning of paravertebral EMG during movement. Within-session reliabilities computed for the full sample ranged from 0.66 to 0.97, and between-session reliabilities, computed on a subset of 29 patients retested after varying intervals, ranged from 0.26 to 0.92. Average EMG levels, flexion, and rotation indices showed no statistically significant differences between surgical (n = 40) and nonsurgical patients (n = 30), although EMG variability was consistently greater for surgical patients across the postures and movements. These results indicate that lumbar paravertebral EMG can be reliably measured and therefore has potential utility as an assessment and treatment variable in CLBP.

Muscle dysfunction in male hypogonadism, Chauhan AK, Katiyar BC, Misra S, Thacker AK, Singh NK.

Acta Neurol Scand. 1986 May;73(5):466-71.

Abstract: Twenty-eight consecutive male patients with primary and secondary hypogonadism (14 each) were evaluated clinically and electrophysiologically for muscle dysfunction. Although generalised muscle weakness was initially reported by only 9 patients, on direct questioning, it was recorded in 19. Objective weakness was found in 13 patients and it involved both the proximal and distal limb muscles. Quantitative electromyography showed evidence of myopathy in the proximal muscle in 25 patients, i.e., reduced MUP duration and amplitude with increased polyphasia in the deltoid and the gluteus maximus. There were no denervation potentials. None of the patients showed clinical neuropathy or NCV abnormalities. Thus, the profile of muscle involvement in hypogonadism closely simulates limb-girdle muscular dystrophy and other endocrine myopathies. The incidence of muscle involvement was higher in secondary hypogonadism. Diminished androgens in primary hypogonadism and diminished growth hormone in the secondary hypogonadism are probably responsible for the myopathy.

Comment: This paper demonstrates what has been demonstrated clinically in AK for many years, namely that endocrine disturbances may often be reflected in muscle dysfunction.

Reflex inhibition of the quadriceps after meniscectomy: lack of association with pain,
Shakespeare DT, Stokes M, Sherman KP, Young A.

Clin Physiol. 1985 Apr;5(2):137-44.

Abstract: We have examined the severity and duration of reflex inhibition of quadriceps activation after arthrotomy and meniscectomy, its relationship with pain, and the effect of local anesthesia on this relationship. Fourteen men, on completion of medial meniscectomy by arthrotomy, received either 10 ml (B10 group) or 15 ml (B15 group) of 0.5% bupivacaine hydrochloride ('Marcaine Plain') into the knee, or no injection (control group). Reflex inhibition of quadriceps was measured as the percentage reduction, from the ipsilateral preoperative value, in the integrated surface electromyogram recorded during maximal voluntary isometric contractions with the knee in extension. Pain during each contraction was recorded on a linear analogue scale. Unoperated limbs showed no evidence of quadriceps inhibition. In the operated limbs, at 1-2 h post-operatively, controls had both severe inhibition (median = 62%) and severe pain on attempting a maximal quadriceps contraction. The B10 group had similar inhibition but less pain (P less than or equal to 0.005, Wilcoxon 2-sample, 1-tailed test). In the B15 group both inhibition (P less than or equal to 0.05) and pain (P less than or equal to 0.01) were less than in the controls. These effects of bupivacaine had been lost by 4-5 h post-operatively. At 3-4 days, inhibition was still severe (median = 75%) in all three groups of patients but pain was only mild or absent. At 10-15 days, median inhibition was still 35%, but there was little or no pain. We conclude that postmeniscectomy inhibition is not simply due to perceived pain but is due, at least in part, to stimuli from the knee.

Quantification of lumbar function. Part 2: Sagittal plane trunk strength in chronic low-back pain patients, Mayer TG,

Smith SS, Keeley J, Mooney V.

Spine. 1985 Oct;10(8):765-72.

Abstract: A prototype sagittal plane trunk strength tester was used to measure trunk strength in 286 chronic low-back pain patients. Initial data for this patient group are compared with data acquired previously from a group of controls, adjusted for age, sex, and body weight. Distinct patterns characterize the patient sample as opposed to the controls: Patient values for both flexors and extensors were markedly decreased, with greater variability; Extensor strength was affected more significantly than flexor strength; Discrepancies between patients and controls were greater for females than for males; High-speed dropoff ratios were much lower for patients, both in flexion and extension. These results demonstrate that strength deficits are a major factor in the deconditioning syndrome associated with chronic low-back pain.

Comment: To test the construct validity of the AK hypothesis that muscle weakness instead of muscle spasm was the cause of spinal pain and dysfunction, researchers have attempted to quantify the muscle weakness that occurs with specific clinical conditions such as low back pain. This paper very elegantly demonstrates one of the prime contentions of AK.

Clinical trials in Duchenne dystrophy. Standardization and reliability of evaluation procedures, Florence JM, Pandya S, King WM, Robison JD, Signore LC, Wentzell M, Province MA.

Phys Ther. 1984 Jan;64(1):41-5.

Abstract: A multiclinic, collaborative study has been designed to assess the natural progression and efficacy of treatment of Duchenne muscular dystrophy. This article describes the protocol for the evaluation technique and the method used to establish within (intraobserver) and between (interobserver) reliability of the protocol evaluation procedures. Standardized patient evaluations were used, and consistency of evaluation was monitored by a computer. The reliability of the measures was analyzed 1) within observers by comparing the results of each of the first three tests done by each evaluator for all patients and 2) between observers by comparing, at multicenter group meetings, the results of each of the four evaluators' tests of the same patient. We have demonstrated reliability for an evaluation method that will provide an objective foundation on which to claim a drug or therapeutic procedure does or does not have an effect in treating Duchenne muscular dystrophy.

Comment: This paper showed that there was significant improvement in the degree of consistency of a given examiner’s MMT scores when the examiner had more clinical experience and training in MMT. Many other researchers of MMT have discussed the importance of considering the examiner’s training upon the outcomes of studies that assess strength via MMT.

Physical measurements as risk indicators for low back trouble over a one year period, Biering-Sorensen, F.

Spine, 1984;9:106-19

Abstract: Of all 30-, 40-, 50-, and 60-year-old inhabitants of Glostrup, a suburb of Copenhagen, 82% (449 men and 479 women) participated in a general health survey, which included a thorough physical examination relating to the lower back. The examination was constituted of anthropometric measurements, flexibility/elasticity measurements of the back and hamstrings, as well as tests for trunk muscle strength and endurance. The reproducibility of the tests was found to be satisfactory. Twelve months after the physical examination 99% of the participants completed a questionnaire sent by mail concerning low back trouble (LBT) in the intervening period. The prognostic value of the physical measurements was evaluated for first-time experience and for recurrence or persistence of LBT by analyses of the separate measurements and discriminant analyses. The main findings were that good isometric endurance of the back muscles may prevent first-time occurrence of LBT in men and that men with hypermobile backs are more liable to contract LBT. Recurrence or persistence of LBT was correlated primarily to the interval since last LBT-episode: the more LBT, the shorter the intervals had been. Weak trunk muscles and reduced flexibility/elasticity of the back and hamstrings were found as residual signs, in particular, among those with recurrence or persistence of LBT in the follow-up year.

Knee joint effusion and quadriceps reflex inhibition in man, Spencer JD, Hayes KC, Alexander IJ.

Arch Phys Med Rehabil. 1984 Apr;65(4):171-7.

Abstract: This study was designed to elucidate the role of effusion in producing the reflex inhibition, and subsequent atrophy, of quadriceps musculature following knee trauma. In particular, consideration was given to determining the extent, threshold and linearity of inhibition of the motoneuron pool induced by experimental introduction of small increments of 0.9% physiological saline (up to 60ml) into the joint space of the knee in ten healthy subjects. Inhibition of the quadriceps muscle motoneuron pool was indirectly assessed through recording Hoffmann (H) reflexes evoked from vastus medialis, lateralis and rectus femoris. All ten subjects showed a significant (p less than 0.05) reduction in H-reflex amplitude following the introduction of saline: vastus medialis reduced to 55.7 +/- 4.3% of its control 0ml value, rectus femoris to 69.1 +/- 6.1% and vastus lateralis to 65.3 +/- 4.0%. Post hoc analyses of the H-reflex amplitudes at each increment of simulated effusion revealed the threshold for reflex inhibition of the vastus medialis to be between 20 and 30ml of saline and for rectus femoris and vastus lateralis to be between 50 and 60ml. These procedures were repeated on eight subjects following an injection of the anesthetic lidocaine (1%) to the intra-articular space of their knee joints but there was no significant reduction in H-reflex amplitude. Linear relationships were found to adequately describe the relationships between the volume of effusion and intra-articular pressure; and volume of effusion and reduction in H-reflex amplitude.

Comment: This paper shows that experimentally induced noninflammatory effusions in the knees of 10 human subjects produced a significant reflexly induced inhibition of the alpha-motoneuron pool of the quadriceps muscles in the absence of pain, joint damage, trauma or movement.Furthermore, they state that the reflex inhibition is blocked by intra-articular anesthesia. They conclude that the inhibition is neurologically mediated in response to changes in articular mechanoreceptive input. Altered muscle tone and mobility are consistently found in AK examination in response to changes of articular or periarticular afferent input.

Musculoskeletal performance testing and profiling of elite competitive fencers, Sapega AA, Minkoff J, Valsamis M,

Nicholas JA.

Clin Sports Med. 1984 Jan;3(1):231-44.

Abstract: Twenty-four male members of the 1976 United States Olympic Fencing Squad were profiled. Data were collected on anthropometry; flexibility; and muscular strength, endurance, and power. Five of the physical variables measured in the laboratory were shown to have a significant relationship to competitive success.

Myofascial origins of low back pain. 1. Principles of diagnosis and treatment, Simons DG, Travell JG.

Postgrad Med. 1983 Feb;73(2):66, 68-70, 73 passim.

Abstract: Myofascial trigger points (TPs) are frequently overlooked sources of acute and chronic low back pain. An active myofascial TP is suspected by its focal tenderness to palpation and by restricted stretch range of motion. The restricted lengthening of the muscle is due to the tense band of muscle fibers in which the TP is located. The presence of a TP is confirmed by a local twitch response and by reproduction of its known pattern of referred pain, which matches the distribution of the patient's pain. Only an active TP causes a clinical pain complaint; a latent TP does not. The pain can be relieved by the stretch-and-spray procedure, ischemic compression, or precise injection of the TP with procaine solution. Relief is usually long lasting only if mechanical and systemic perpetuating factors are corrected.

Comment: The work of Dr. Janet Travell has influenced allopathic and complimentary and alternative medicine and is one of the foundations of AK.

Myofascial origins of low back pain. 2. Torso muscles,
Simons DG, Travell JG.

Postgrad Med. 1983 Feb;73(2):81-92.

Abstract: Trigger points (TPs) in muscles of the lower torso associated with the spine are an important cause of low back pain. The quadratus lumborum is the muscle most commonly involved, but TPs located there are often overlooked because of inadequate physical examination techniques. TPs in the lower rectus abdominis refer pain horizontally across the low back, and those in the iliopsoas refer pain in a vertical pattern, parallel to the lumbosacral spine. The pain pattern of TPs in the serratus posterior inferior is noted in the region of the muscle itself.

Myofascial origins of low back pain. 3. Pelvic and lower extremity muscles,
Simons DG, Travell JG.

Postgrad Med. 1983 Feb;73(2):99-105, 108.

Abstract: Gluteal, pelvic, and lower extremity muscles are common sites of origin of myofascial low back pain. Trigger points (TPs) in the gluteus maximus and medius muscles refer pain locally to the gluteal and sacral regions, while those in the gluteus minimus are likely to refer pain down the lower extremity as far as the ankle on the same side. TPs in intrapelvic muscles refer pain chiefly to the pelvic region. Besides producing referred myofascial pain, TPs in the piriformis muscle can cause symptoms of entrapment of the peroneal portion or all of the sciatic nerve. TPs in the soleus muscle may refer pain to the sacroiliac joint.

Effects of manipulation on gait muscle activity: preliminary electromyographic research, Hibbard D.

J Am Chiro Assoc 1983;17:49-51

The efficacy of manual assessment of muscle strength using a new device, Marino M, Nicholas JA, Gleim GW, Rosenthal P, Nicholas SJ.

Am J Sports Med. 1982 Nov-Dec;10(6):360-4

Abstract: The purpose of this study was to compare the manual assessment of muscle strength with a small, handheld (by the examiner) force-measuring device developed by the Institute of Sports Medicine and Athletic Trauma (ISMAT). One hundred twenty-eight patients presented with a known lower extremity orthopaedic pathology. All patients were clinically evaluated for hip abductor and hip flexor weakness in standard positions using the "break test" technique. All 128 patients were then evaluated with the ISMAT Manual Muscle Tester, a small, hand-held device which recorded the peak force (kg) required to break a muscle contraction. Three bilateral measures of hip abduction and hip flexion were recorded, averaged, and compared to the subjective clinical evaluation using a chisquare analysis. Bilateral values which were within 5% of each other were not considered significant and therefore not included in the calculations. The average hip abduction and hip flexion scores measured by the ISMAT tester were consistent with the examiner's perception of muscle weakness (P less than 0.001). The results demonstrate consistent detection of muscle weakness by the ISMAT Manual Muscle tester over a broad range of testing conditions.

Comment: The MMTs employed in this study used the standard positions delineated by Kendall and Kendall and the ones used in AK, specifically for the rectus femoris and gluteus medius muscles.

Electromyographic analysis following chiropractic manipulation of the cervical spine: a model to study manipulation-induced peripheral muscle changes, Rebechini-Zasadny H, Tasharski C, Heinze, W.

J Manipulative Physiol Ther 1981;4:61-63

This study showed the effects of chiropractic manipulation upon the musculature of 12 volunteers, specifically an increase in finger strength after cervical adjusting.

Investigation of over-the-skin electrical stimulation parameters for different normal muscles and subjects, Moreno-Aranda J, Seireg A.

J Biomech. 1981;14(9):587-93

Usefulness of electrophysiological studies in the diagnosis of lumbosacral root disease, Tonzola R, Ackil A, Shahani B, Young R.

Ann Neurol 1981;9:305-308

Abstract: Clinical, electrophysiological, and myelographic findings were correlated in 57 patients with the clinical diagnosis of lumbosacral root disease. Conventional motor and sensory (including sural nerve) conduction studies were normal in all patients. Electromyography, late response studies in different muscles of the lower extremity, the myelogram, or combinations of these tests were abnormal in 44 patients (77%). Of 36 patients (63%) with abnormal myelograms, 14 had normal electrophysiological studies. Twenty-nine (51%) had an abnormal electrophysiological or myelographic finding; although 8 patients in this group had a normal myelogram, 2 had an abnormal discogram and 1 an abnormal epidurogram. Electrophysiological or myelographic findings, in some cases both, correlated well with clinical signs and symptoms in 41 patients (72%). H-reflex and F response studies, when abnormal, helped in localizing a lesion in the appropriate root distribution.

Comment: This study demonstrates that EMG shows better correlation with neurological examinations than CT scans or myelograms for nerve root disturbances in the lumbosacral spine. In other words, muscle dysfunction correlates better with lumbosacral nerve root injuries than CT scans or myelograms.

Trunk strengths in attempted flexion, extension, and lateral bending in healthy subjects and patients with low-back disorders, McNeill T, Warwick D, Andersson G, Schultz A.

Spine. 1980 Nov-Dec;5(6):529-38.

Abstract: Trunk strengths were measured in 27 health males and 30 health females, and in 25 male and 15 female patients with low-back pain and/or sciatica. Maximum voluntary isometric strengths were measured during attempted flexion, extension, and lateral bending from an upright standing position. Both male and female patients had approximately 60% of the absolute trunk strengths of the corresponding healthy subjects. Intra-individual trunk strength ratios were used to interpret the results. Use of these ratios tends to avoid interpretational problems created by the general weakness of the patients and any lack of motivation of either patients or healthy subjects. The ratios showed that the patients had attempted extension strengths that were significantly less than their strengths in the other types of movements tested. The strength ratios for attempted extension were particularly low for patients with sciatica.

Trunk strengths in patients seeking hospitalization for chronic low-back disorders, Addison R, Schultz A.

Spine. 1980 Nov-Dec;5(6):539-44.

Abstract: Trunk strengths of 16 male and 17 female patients with chronic low-back disorders were measured. The patients sought hospitalization for four weeks in a pain clinic. Maximum voluntary trunk strengths in the standing position were measured during attempted flexion, extension, and lateral bending. The trunk strengths of these patients were then compared with those of health subjects and with those of patients with low-back disorders who sought treatment as outpatients of a general orthopaedic office practice. In making the comparisons, intra-individual trunk-strength ratios were used to overcome problems due to the effects of patients' general weakness and any psychologic factors. When compared with healthy subjects, the patients seeking hospitalization had significantly smaller strengths during attempted extension relative to their strengths during attempted flexion or lateral bending. Their trunk-strength ratios did not differ significantly from those of the outpatient group.

Back and leg complaints in relation to muscle strength in young men, Karvonen MJ, Viitasalo JT, Komi PV, Nummi J, Jarvinen T.

Scand J Rehabil Med. 1980;12(2):53-9.

Abstract: Back and leg complaints were studied by using a questionnaire and medical examination in 183 male conscripts and relating the results to background variables, anthropometry, the isometric strength of large muscle groups, and endurance running. A history of sciatica was reported by 8%, lumbago by 13%, back injury by 13% and low back insufficiency by 63%. Weak trunk extensors were associated with a history of sciatica, weak trunk flexors with back injuries and with current backache at work/exercise. Weak leg extensors showed associations with a history of low back insufficiency and of sick leave due to the back and with current hip pain. Men with a history of lumbago and of hip and knee complaints performed poorly during 12 min of running. Back and leg complaints were more frequent in men with high socio-economic status, who engaged in little physical activity, or who were obese. The questionnaire and strength measurements proved suitable for studying low back syndrome in its early stages.

The Application of Neurological Reflexes to the Treatment of Hypertension, Mannino, R.

Journal of the American Osteopathic Association, Dec 1979:225-230

Factors influencing manual muscle tests in physical therapy, Nicholas JA, Sapega A, Kraus H, Webb JN.

J Bone Joint Surg Am. 1978 Mar;60(2):186-90

Abstract: To determine whether it is the amount or the duration of the force applied manually by the tester, or both, that determines the tester's perception of the strength of the hip flexor or abductor muscles, an electromechanical device was designed which was placed between the tester's hand and the subject's limb. With the device we measured the force applied to the limb, the time interval during which it was applied, and the angular position of the limb during the entire test. In 240 such tests, the testers' ratings of the differences in strength between the right and left sides were correlated with seven variables involving force and time. It was found statistically that the impluse--that is, the duration of the tester's effort multiplied by the average applied force during each test--was the factor that most influenced the tester in the ratings.

Comment: The skills of the examiner related to conducting tests and interpreting the derived information will affect the usefulness of muscle performance data.The examiner is obliged to follow a standardized protocol that specifies patient position, verbal instructions or demonstration to the patient, alignment of the muscle and direction of examiner resistance to insure precise, repeatable, and reliable MMT results. When a muscle is tested in voluntary isometric contraction, EMG testing reveals that additional muscle fibers contract at low forces; when the force increases, the rate of firing becomes the predominant mechanism to increase strength. Tension, velocity, and electrical activity are interdependent and indicate the importance of proper neurologic control for the muscle to meet the changing pressure demands of the MMT. This requires effective function of the gamma system adjusting the neuromuscular spindle cell, and proper interpretation of its afferent supply by the central nervous system. Thus it is patient or more precisely the patient’s neuromuscular adaptive capacity that is being examined during a proper MMT.

Muscular Strength Correlated to Jaw Posture and the Temporomandibular Joint – Examination of a Professional Football Population, Smith, S.D.

New York State Dental Journal, 44(7);Aug/Sept 1978

The use of skin stimulation to produce reversal of motor unit recruitment order during voluntary muscle contraction in man [proceedings], Buller NP, Garnett R, Stephens JA.

J Physiol. 1978 Apr;277:1P-2P.

This paper demonstrates the specific effect of skin stimulation upon muscle function, and shows the neurological relationships that may be occurring during the therapy localization procedure in AK diagnosis and treatment.

Reversal of recruitment order of single motor units produced by cutaneous stimulation during voluntary muscle contraction in man, Stephens JA, Garnett R,

Buller NP.

Nature. 1978 Mar 23;272(5651):362-4.

This paper demonstrates the specific effect of skin stimulation upon muscle function, and shows the neurological relationships that may be occurring during the therapy localization procedure in AK diagnosis and treatment.

Discogenic radiculopathy: use of electromyography in multidisciplinary management, Lane M, Tamhankar M, Demopoulos J.

NY State J Med 1978;78:32-36

This study demonstrated an 85% agreement between EMG evaluation and neurological work-up, evidencing nerve root compromise. There is evidence offered that EMG readings may be equivalent to subluxation determination. This study shows that changes in muscle electrical activity measured in distinct myotomes revealed nerve root disturbance. The study concludes that a positive EMG finding, indicating the presence of a lesion at the level of the root or proximal in the spinal cord, should alert the clinician.

A study of thigh muscle weakness in different pathological states of the lower extremity, Nicholas JA, Strizak AM, Veras G.

Am J Sports Med. 1976 Nov-Dec;4(6):241-8.

Grip strength and chiropractic adjustment, Howitt Wilson MB.

Anglo-European College of Chiropractic, 1975.

Abstract: Six student controls and 50 patients had their grip strength measured with a sphygmomanometer after CMT to the T1 vertebra. 21 patients had significant contralateral grip strength increases.

Towards standardization of muscle strength testing, Kroemer KH, Howard JM.

Med Sci Sports. 1970 Winter;2(4):224-30

Abstract: Male subjects (N=24) exerted maximal horizontal forces either trying to maintain a constant level over 5 seconds, or increasing steadily to the subjective maximum, or in vigorous jerks of the body. Statistical analysis (p<0.01) indicated that these different techniques of force generation can result in different peak impulses. For the force maintained over 5 seconds, different scores (peak, and 12 averages during the exertion period) were extracted from the recorded force curves. Many of the resulting scores were significantly different from the others. Thus, a number of distinctly different “strength” scores resulted either from techniques of force generation used by the subjects, or from different statistical treatments of the same raw data by the experimenter. To standardize measures of “strength,” a definition of strength, a checklist to control experimental techniques, and a regimen to calculate the strength index are proposed.

Dysponesis: a neurophysiologic factor in functional disorders,

Whatmore GB, Kohi DR.

Behav Sci. 1968 Mar;13(2):102-24.

Abstract: Dysponesis is described as a reversible patho-physiologic state consisting of unnoticed, misdirected neurophysiologic reactions to various agents (environmental agents, body sensations, emotions and thoughts) and the repercussions of these reactions throughout the organism.

Comment: In AK it is proposed that these errors in energy expenditure, potentially capable of producing functional disorders, consist mainly of covert errors in action potential output from the motor and premotor areas of the cerebral cortex and include the consequences of that output. These neurophysiologic events result in aberrant muscle activity that may be evaluated through manual muscle testing technique.

Cord cells responding to fine myelinated afferents from viscera, muscle and skin,

Pomeranz B, Wall PD, Weber WV.

J Physiol. 1968 December; 199(3): 511–532.

Abstract: 1. Micro-electrode recordings were made in the thoracic cord of acute spinal cats. Cells, which were located in the histologically defined lamina 5, responded both to the fine myelinated afferents from the splanchnic nerve and to afferents from the skin. Splanchnic afferents inhibit the effect of converging cutaneous inputs for periods up to 150 msec. Skin stimuli may also inhibit the effect of afferent nerve impulses from viscera. Some cells respond monosynaptically to the splanchnic afferents, others indirectly.

2. Fine myelinated afferents from gastrocnemius (group 3) stimulate lamina 5 cells which also have cutaneous receptive fields. Cutaneous and group 3 muscle afferents interact by mutual inhibition in their effect on the cells.

3. Fine myelinated afferents from skin excite lamina 5 cells. The cutaneous responses of lamina 5 cells contrast with those of lamina 4 cells in the following respects: (a) the receptive fields are larger, (b) they respond with an increased latency to Aβ afferents, (c) there is a low pressure threshold at the edge, (d) they respond to a wide range of pressure stimuli from light brush to heavy pinch applied to the centre of the receptive fields and (e) they respond to A afferents.

4. Lamina 5 cells receive fine myelinated afferents either from viscera or from muscle or from skin. Lamina 4 receives large myelinated afferents from skin and lamina 6 receives large myelinated afferents from muscle. The results suggest the hypothesis that some fine myelinated afferents form a class of afferents which signal the state of tissue, and end on lamina 5 cells.

Comment: This early paper describes the neurology involved in the AK testing method called Therapy Localization. In AK, TL is a simple, non-invasive technique to find out where a problem in the body exists. TL doesn’t show the physician what the problem is but shows that something under the hand that is contacting the patient’s body is disturbing the nervous system.

An Introduction to Chapman’s Reflexes, Chaitow, L.

British Naturopathic Journal, Spring 1965

Muscle testing. Part 2:Reliability in clinical use, Iddings DM, Smith LK, Spencer WA.

Phys Ther Rev 1961;41:249-256.

Quantitative muscle testing: Principles and applications to research and clinical services, Beasley W

Arch Phys Med Rehabil 1961;42:398-425

Study of the reproducibility of muscle testing and certain other aspects of muscle scoring, Lilienfeld AM, Jacobs M, Willis M.

Phys Ther Rev 1961;41:249-256.

Excitatory and inhibitory skin areas for flexor and extensor motoneurons, Hagbarth KE.

Acta Physiol Scand Suppl. 1952;26(94):1-58.

Comment: This early paper describes some of the neurology involved in the AK testing method called Therapy Localization. In AK, TL is a simple, non-invasive technique to find out where a problem in the body exists. TL doesn’t show the physician what the problem is but shows that something under the hand that is contacting the patient’s body is disturbing the nervous system.

Some interesting observations about the after care of infantile paralysis patients, Kendall HO

J Excep Child 1936;3:107.

A method of recording muscle tests, Lowman CL.

Am J Surg 1927;3:586-591.

Abstract: It has been quite generally accepted that muscle reeducation, as applied particularly to paralysis causes, is of very decided value in treatment. A grading system for muscle measurement is delineated, ranging from 0 (no appreciable motion) to 9 (normal muscle strength and motion). Allowance must be made for the personal equation which usually accounts for at least a variance of one degree between examiners. Preferably the same persons should make all the tests, and the longer they do this the more reliable they become.

Certain aspects of infantile paralysis with a description

of a method of muscle testing, Lovett RW, Martin EG.

JAMA.1916 Mar 4; LXVI(10):729-33.

A method of testing muscular strength in infantile

Paralysis, Martin EG, Lovett RW. 

JAMA. 1915 Oct 30; LXV(18):1512-3.

Treatment of infantile paralysis, Lovett RW.

JAMA 1915;64:2118

Muscle training in the treatment of infantile paralysis, Wright WG.

Boston Med Surg J 1912;167:567-574.