Muscle testing, often referred to as Applied Kinesiology (AK), is a diagnostic technique used in complementary and alternative medicine (CAM) that claims to assess a person’s health. The practice involves a practitioner evaluating the perceived strength or weakness of a patient’s muscle in response to different stimuli, which is then interpreted to find imbalances. This method is distinct from the standard manual muscle testing used in conventional medicine to grade physical strength after injury or disease. The use of AK as a diagnostic tool is a subject of significant controversy regarding its scientific foundation and effectiveness.
Defining the Practice of Muscle Testing
The core procedure involves the patient holding a limb, typically an arm, in a specific position while resisting a light, steady force applied by the practitioner. The practitioner subjectively evaluates the muscle’s ability to “lock” and maintain resistance. A resistant response is interpreted as “strong,” while a response that gives way is deemed “weak.”
This test is performed first to establish a baseline and then repeated after introducing a challenge or stimulus. Challenges might involve the patient holding a food substance, a supplement vial, or touching a specific body part. If the muscle becomes weak after the stimulus, the practitioner interprets this change as an indicator of dysfunction, imbalance, or a negative reaction. The difference observed is a subjective evaluation of the muscle’s neurological response, not a raw measure of physical strength.
The Theoretical Basis of Applied Kinesiology
Applied Kinesiology was developed in 1964 by chiropractor George Goodheart Jr., adapting conventional manual muscle testing with concepts from Eastern medicine. The central premise of AK is that a specific muscle weakness correlates with dysfunction in a corresponding internal organ or gland, known as the viscerosomatic relationship. The nervous system is believed to communicate the state of internal health through the strength of certain muscles.
Proponents of AK incorporate concepts like traditional Chinese meridians and energy flow to explain this muscle-organ connection. They claim that a disruption in energy along a meridian, or a problem with a specific organ, manifests as a weak muscle associated with that system. This diagnostic approach aims to evaluate the body’s structural, chemical, and emotional aspects, often focusing on identifying nutritional deficiencies or sensitivities.
Evaluating Scientific Validity and Reproducibility
The consensus among major medical and scientific organizations is that Applied Kinesiology lacks diagnostic validity. Controlled studies attempting to validate the AK method have consistently failed to demonstrate that muscle testing can reliably diagnose physical or mental conditions. The primary issue is the lack of reproducibility, as different examiners often get different results on the same patient, and even the same examiner struggles to get consistent results.
Double-blind, randomized trials, considered the gold standard for scientific testing, show that AK results are often no better than random guessing. Studies testing AK’s ability to identify toxic substances or allergens found that kinesiologists identify the substance at a rate statistically similar to chance. Furthermore, there is no known plausible biological or physiological mechanism linking the brief, light pressure applied during AK testing to the function of distant internal organs or substance sensitivity.
The standard orthopedic manual muscle test is a legitimate tool for measuring physical strength, but the AK adaptation claiming to diagnose internal disease is not supported by evidence. A review of AK-specific procedures concluded that studies meeting accepted scientific standards either refute the validity of AK or cannot support its use as a reliable diagnostic tool. Organizations like the American College of Allergy, Asthma and Immunology have explicitly stated there is no evidence to support the diagnostic use of applied kinesiology.
Psychological Factors Driving Perceived Effectiveness
The lack of scientific support for muscle testing does not negate that many patients and practitioners genuinely believe it works. This perceived effectiveness is often explained by well-documented psychological phenomena. One significant factor is the Ideomotor Effect, which describes unconscious muscle movements triggered by thought or expectation. The practitioner, anticipating an outcome, may involuntarily vary the pressure applied, causing the patient’s muscle to “give” without conscious intent.
The power of suggestion also plays a role, as the practitioner’s leading questions or body language can influence the patient’s physical response and the interpretation of the result. Confirmation bias is another factor, where both the practitioner and the patient focus on results that confirm their existing beliefs about a health problem or treatment. Finally, the Placebo Effect contributes by allowing the expectation of benefit to drive perceived results, increasing patient confidence in the resulting treatment plan.