APPPLIED KINESIOLOGY AND CHIROPRACTIC

APPLIED KINESIOLOGY: MANUAL MUSCLE TESTING AND THE MOTOR NEURON

RICHARD BELLI, D.C.

Research Advisory Chairman. International College of Applied Kinesiology ‑ U.S.A.

Manual muscle testing ties been a tool for medical and chiropractic evaluation for decades. The use of manual muscle testing as a tool in the medical community is mainly limited to evaluation of pathology whereas, in the chiropractic community it has been used for evaluation of functional disorders‑ It took the genius of George Goodheart, D.C. to see the value of manual muscle testing as an evaluative tool for functional disorders of the human system. His discovery earmarked the beginning of Applied Kinesiology (AK), Years later, Walter Schmitt Jr., D.C. coined the term,, "muscle testing as functional neurology", that started the era of describing the functional neurological aspects of manual muscle testing, and realization of the breadth of possibilities that manual muscle testing affords.

Over the decades that muscle testing has been used as an analytical tool, there have been a multitude of meanings attached to a weak muscle. These include dysfunction of the electromagnetic system, the lymphatic system, the cranial respiratory system, and many more‑ But whatever you mute the zebra, a zebra is a zebra, and the bottom line in AK is that a "weak response" to a muscle test means that the muscle's motor neuron is not functioning normally, limiting the ability of the subject to contract the muscle. In other words, if the motor neuron is shifted too far towards hyperpolarization then the subject cannot depolarize the motor neuron enough to provoke a muscle contraction and the muscle tests weak. This leaves us with the question, "What does a weak muscle mean"?

The term "weak muscle", in respect to AK, is actually a misnomer. The muscle itself is not actually weak. Assuming there is no end organ pathology, the "weakness" is the result of inhibition of the motor neuron.. A muscle is simply contractile tissue that is depolarized by an efferent signal from the motor neuron. A weak muscle simply means that the muscle being tested is not appropriately depolarized by the motor neuron` Therefore, a more appropriate term would be a "neurologically inhibited muscle". Hence one who uses manual muscle testing as an analysis tool needs to realize that muscle testing is simply a test of the function of the motor neuron.

The anterior horn of the spinal cord is the location of the cell body of the motor neuron. The functional state of the anterior horn is maintained by convergence of multiple ascending and descending pathways. The descending pathways originate at suprasegmental levels both pyramidally and extra pyramidally. The ascending pathways are sensory pathways that are either of somatic or visceral origin. The descending pathways can be of conscious origin in which the subject voluntarily motivates the muscle, or it can be of reflexogenic origin that is involuntary. Ascending pathways may be sensory from a variety of origins ranging from mechanoreceptors its skin and joints to nociceptive fibers from soma and viscera, In an occurrence of a weak muscle, the total effect of the converging pathways may shift the anterior horn so far towards hyperpoluization that the neuron cannot be brought to it's firing threshold, thus when the examiner tests the muscle the subject cannot resist the force of the examiner.

There are a variety of reflexes indigenous to the human system that are necessary to maintain life and limb. If there is either somatic or visceral tissue dysfunction there will be an associated reflex affecting motoneurons and muscle function. A classic example is an inflamed appendix in which the patient cannot extend the right hip. This flexion contraction is a withdrawal reflex that is a consequence of tissue irritation and a nociceptive drivers withdrawal reflex. For every hypertonic muscle due loss of appropriate inhibition of its' motor neuron, there will be a reflexogenic inhibition or "weakness" of its' opposing muscle. As a result, nearly every visceral or somatic dysfunction will result in a neurologically inhibited muscle‑ Lesser degrees of this exampe come in the form of the weak muscles that are examined with manual muscle testing.

The nervous system monitors and drives virtually all the systems in the human body. When there is dysfunction of any part of the human system the central nervous system knows about it, and attempts to respond accordingly. The soma and viscera communicate with the central nervous system both chemically And neurologically. Therefore it is reasonable to say that both chemical and neurological dysfunction can be analyzed with manual muscle testing.

Regardless of the name of the technique used, whether it is acupuncture meridian stimulation, neurolymphatic technique, spinal adjusting or other osseous manipulation, if it strengthens a muscle it is bringing the anterior horn and associated motor neuron to a more normal state of function.

Hardly a single human function takes place without involvement of muscles. With that in mind, and proficient knowledge of the human nervous system, the use of manual muscle testing in the form of Applied Kinesiology can provide an almost limitless tool for functional analysis of the nervous system and all that effects it.