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Dynamic Chiropractic – January 1, 2008, Vol. 26, Issue 01

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In Defense of the Functional Manual Muscle Test

It is with great dismay that I read the diatribe by Dr. Stephen Perle in the Nov. 19 issue of Dynamic Chiropractic.1

The dismay is not that he might offer some valid critique or helpful suggestions for further research, but that without careful reading, an emotional tone is palpable.

When emotions are so obviously discharged, they betray a less than careful thinking process, and that appears to be the case when it comes to Dr. Perle and applied kinesiology (AK). Perle's own chiropractic history is instructive2 (going from passionate AK practitioner to ceaseless AK critic for over a decade), showing how blind faith and skepticism often turn into each other if someone is logical enough, or mad enough, to pursue the argument to that point of abstract consistency where ordinary common sense is left behind in the rush for certitude. Dr. Perle attempts to provoke, instead of assisting the chiropractic clinical and research communities to share and grow together.

The operational definition of the manual muscle test (MMT) used by physical therapists, neurologists and orthopedists is the same as that used by chiropractors who use standardized MMT methods taught in AK. This is why our peer-reviewed presentation of the clinical trials covering the reliability and validity of the MMT included the work of associated disciplines that use the MMT.3 Similarly, in any literature review of clinical trials for high-velocity low-amplitude (HVLA) spinal manipulative therapy (SMT) for low back pain, the outcomes from the medical or osteopathic fields would be part of the evidence base for assessment of the value of this mode of therapy for LBP.

After their original book on the MMT, Kendall and Kendall's second book was called Posture and Pain (1952). It was already realized that the theoretical construct of the MMT should be expanded far beyond the "polio syndromes" that the MMT was originally designed to evaluate.4 Using the detailed records from 12,000 cases, they state, "The importance of muscle testing in cases of postural disorders cannot be over-emphasized."

The AMA, in its Guides to the Evaluation of Permanent Impairment, 5th edition, also has accepted the MMT as a reliable and valid method for evaluating functional, non-pathological, non-radicular and non-organic injuries (despite Perle, et al.)!5 AK is attempting to lay a foundation for the MMT in chiropractic neuromuscular diagnosis, assessment, and treatment, which is an important part of the AK therapeutic intervention. To employ a reliable and valid, safe and cost-effective test such as the MMT, one that could reliably assess a patient's presentation and response to treatment, would seem reasonable.

Research from Goodheart and the ICAK, Lewit and Janda has identified specific joint dysfunctions that are linked to individual dysfunctional muscles that can be assessed with MMT.6-9 Janda has written a book suggesting that the MMT is useful for many more functional conditions than the ones Perle, et al., would delimit it to.9 However, before it can be used this way we needed to demonstrate that the MMT has good reliability and validity as a diagnostic test. Our review in the journal Chiropractic and Osteopathy presented the evidence that the MMT does have good-to-excellent reliability and validity. The accepted use of the MMT in neurologic, medical, physical therapy, and orthopedic domains for decades attests to this.4-9

So, why is there a problem when chiropractors employ the MMT? It appears that Dr. Perle abreacts primarily when the name AK accompanies the term MMT. If a patient's radicular pain peripheralizes, it is accepted in research circles that their condition is worsening.10 If a patient's muscle strength weakens, this likewise indicates that their condition is worsening.

Muscle weakness commonly indicates neurological and/or orthopedic changes in the joint, muscles or nerve supply.4-9 If the patient has increased strength during the course of treatment, immediately or over time, this would be considered a positive result as well.

The International College of Applied Kinesiology (ICAK) is working diligently to bring the AK chiropractic technique into the evidence-based arena.11 Our article discussing the reliability and validity of the MMT as a viable chiropractic assessment tool is an important foundation for AK further research protocols evaluating and treating neuromuscular dysfunction.

For less biased thinkers, there is sufficient research evidence to support the reliability and validity of the MMT. Assessing the function of muscles with the MMT pre- and post-treatment can assess the benefit of a therapeutic intervention: Does the therapy improve or worsen muscle function? This assessment process is the basis of AK.


  1. Perle S. "Intellectual Honesty." Dynamic Chiropractic, 2007;25(24). Available at
  2. Perle S. Applied Kinesiology (AK). Chiro Technique, Aug. 1995;7(3):103-107.
  3. Cuthbert SC, Goodheart GJ Jr. On the reliability and validity of manual muscle testing: a literature review. Chiropr Osteopat, March 6, 2007;15(1):4.
  4. Kendall HO, Kendall FP. Posture and Pain. Williams & Wilkins, Baltimore, MD, 1952.
  5. Guides to the Evaluation of Permanent Impairment, 5th Edition. American Medical Association, 2001:510.
  6. Goodheart GJ. Applied Kinesiology Research Manuals. Published annually, 1964-1998.
  7. Janda V. Muscle Strength in Relation to Muscle Length, Pain and Muscle Imbalance. In: Harms-Ringdahl K (ed.): Muscle Strength. New York: Churchill Livingstone, 1993:83-91.
  8. Lewit K. Manipulative Therapy in Rehabilitation of the Locomotor System, 2nd edition. Butterworth-Heinemann, Oxford, 1991:142-143.
  9. Janda V. Muscle Function Testing. Butterworths, London, 1983.
  10. Aina A, May S, Clare H. The centralization phenomenon of spinal symptoms - a systematic review. Man Ther, 2004;9(3):134-43.
  11. ICAK-International and ICAK-USA Web sites: "Applied Kinesiology Research and Literature Compendium" [] and [ Accessed Nov. 18, 2007.

Scott Cuthbert, DC
ICAK-USA board member

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