Influence of foot orthotics upon duration of effects of spinal manipulation in chronic back pain patients: a randomized clinical trial.

OBJECTIVE: The purpose of this study was to investigate the effects of 4 weeks of custom foot orthotics on pain, disability, recurrence of spinal fixation, and muscle dysfunction in adult low back pain patients receiving limited chiropractic care. METHODS: Adult volunteers with low back pain of greater than or equal to 1 month's duration were randomized to receive custom orthotics (group A) or a flat insole sham (group B) with limited chiropractic care in 5 visits over 4 weeks. Primary outcome measures are as follows: Quadruple Numerical Pain Rating Scale (for back), the Roland-Morris Disability Questionnaire, the number of muscles grade 4 or lower on manual muscle testing, and the number of spinal fixations detected by motion palpation and vertebral challenge at intake (B1), 2 weeks later before treatment began and orthotic use was initiated (B2) and before each subsequent treatment at approximately days 3, 10, 17, and 24 after B2. Secondary outcome measures are correlations of all primary outcomes. RESULTS: Both groups improved on all Numerical Pain Rating Scale, Roland-Morris Disability Questionnaire, and the number of muscles from intake (B1) to final visit. Only group B yielded significant improvements in the number of spinal fixations. No outcome measures showed statistical difference between groups at any time point; however, those who wore custom orthotics longer each day showed trends toward greater improvements in some outcome measures. CONCLUSIONS: Both groups improved with chiropractic care including spinal manipulation; however, there were no statistical differences shown between sham and custom orthotic groups. Future studies should formally measure the time that orthotics or shams are worn in a weight-bearing capacity each day.

A narrative review of manual muscle testing and implications for muscle testing research.

OBJECTIVE: Manual muscle testing (MMT) is used for a variety of purposes in health care by medical, osteopathic, chiropractic, physical therapy, rehabilitation, and athletic training professionals. The purpose of this study is to provide a narrative review of variations in techniques, durations, and forces used in MMT putting applied kinesiology (AK) muscle testing in context and highlighting aspects of muscle testing important to report in MMT research. METHOD: PubMed, the Collected Papers of the International College of Applied Kinesiology-USA, and related texts were searched on the subjects of MMT, maximum voluntary isometric contraction testing, and make/break testing. Force parameters (magnitude, duration, timing of application), testing variations of MMT, and normative data were collected and evaluated. RESULTS: "Break" tests aim to evaluate the muscle's ability to resist a gradually increasing pressure and may test different aspects of neuromuscular control than tests against fixed resistances. Applied kinesiologists use submaximal manual break tests and a binary grading scale to test short-term changes in muscle function in response to challenges. Many of the studies reviewed were not consistent in reporting parameters for testing. CONCLUSIONS: To increase the chances for replication, studies using MMT should specify parameters of the tests used, such as exact procedures and instrumentation, duration of test, peak force, and timing of application of force.

Intraexaminer comparison of applied kinesiology manual muscle testing of varying durations: a pilot study.

OBJECTIVE: The purpose of this study is to investigate the difference in results (strong/facilitated vs weak/functionally inhibited) between short (1 second) and long (3 seconds) manual muscle tests (MMTs) on the same subject and to pilot the use of thin-film force transducers for characterizing the parameters of MMT and for measuring maximum voluntary isometric contraction (MVIC). METHOD: Forty-four healthy chiropractic students were tested. A thin-film force transducer recorded force over time during MVIC of the middle deltoid and 1- and 3-second MMTs of the same subjects. The MMTs were graded as strong (able to resist the testing pressure) or weak (unable to resist testing pressure, breaking away). RESULTS: Forty-two short tests were strong, and 2 were weak. Thirty-nine long tests were strong, and 5 were weak. κ (0.54) showed fair agreement for results between short and long tests. Peak force in both short and long weak tests was higher than that in strong tests when expressed as a proportion of maximum contraction. All manual tests used less force than MVICs. CONCLUSIONS: This study demonstrated that a study of this nature is feasible. Longer test durations demonstrate some muscle weaknesses that are not evident on 1-second MMTs. Thin-film transducers show promise for recording MMT parameters for research purposes.