Muscle testing, formally known as Applied Kinesiology (AK), is a diagnostic technique originating in alternative medicine. It operates on the premise that manual muscle strength testing can reveal information about the body’s overall function, extending far beyond the physical capacity of the muscle itself. Practitioners, including some chiropractors and naturopaths, use this method to identify perceived imbalances ranging from nutritional deficiencies to organ stress. The validity of AK as a diagnostic tool is widely debated, necessitating an examination of the scientific evidence.
Defining Applied Kinesiology
Applied Kinesiology was developed in 1964 by American chiropractor George Goodheart, Jr. The core procedure involves the patient holding a limb in a specific position while the practitioner applies a quick, steady force against the muscle, which the patient is instructed to resist. The practitioner evaluates the muscle’s response, judging it as either “strong” or “weak” based on its ability to maintain position against the force. This technique differs significantly from conventional manual muscle testing, which assesses purely neurological and orthopedic function.
AK is often performed while the patient is exposed to a stimulus, such as holding a supplement or touching a specific area. If a previously “strong” muscle suddenly exhibits a “weak” response, practitioners interpret this as a sign of an imbalance or stressor. This process is viewed as a form of biofeedback, where the muscle’s response indicates the nervous system’s function rather than the muscle’s absolute strength.
The Rationale Behind Muscle Testing
The theoretical claims underpinning Applied Kinesiology are rooted in a holistic view of health, proposing that the body’s structural, chemical, and emotional components are interconnected. Practitioners claim that a weakness in a specific muscle correlates directly with a problem in a corresponding organ or gland, known as the viscerosomatic relationship. This link suggests that internal organ dysfunction manifests as specific muscle weakness, which the test is intended to reveal.
AK also posits that muscle strength changes instantaneously in response to exposure to substances like allergens or nutritionally deficient foods. For example, holding an unhealthy substance will cause a previously strong muscle to weaken, indicating the body is negatively affected. Furthermore, the system incorporates concepts from Traditional Chinese Medicine, suggesting that imbalances in the body’s energy pathways, or meridians, can be detected through changes in muscle tone.
Scientific Evidence and Standardization
Controlled scientific studies have consistently failed to validate the diagnostic claims of Applied Kinesiology. A fundamental issue is the lack of standardization and reliability; different practitioners often arrive at different diagnoses for the same patient, and results can be inconsistent even with the same practitioner. When researchers have attempted to replicate AK’s findings under controlled, double-blind conditions, the technique has generally performed no better than random chance.
Double-blind studies are used to eliminate the influence of suggestion or expectation from both the patient and the practitioner. In studies testing AK’s ability to diagnose nutritional deficiencies or food allergies, practitioners were unable to correctly identify the test substance when blinded to its identity. For instance, a 2014 study found that the accuracy of identifying a toxic substance was around 53%, which is statistically indistinguishable from a random guess. Major medical organizations, including the American College of Allergy, Asthma and Immunology, conclude there is no evidence to support the diagnostic validity of Applied Kinesiology for conditions like allergies.
Psychological Factors in Perceived Success
The perceived success of muscle testing often involves several psychological mechanisms unrelated to physiological diagnosis. One factor is the placebo effect, where a patient’s belief in the treatment and the practitioner’s confident approach can lead to a perceived or actual improvement in symptoms. Receiving focused attention and a tailored diagnosis can be highly therapeutic, regardless of the test’s scientific merit.
Another strong influence is the ideomotor effect, which involves involuntary, subconscious muscle movements. Practitioners may unknowingly vary the force applied to the patient’s limb, subtly communicating the expected outcome. The patient’s muscle response then involuntarily complies. This subconscious feedback loop leads both the patient and the practitioner to genuinely believe the test is working, a phenomenon reinforced by confirmation bias. Patients tend to remember times the results align with expectations while overlooking instances where the results were ambiguous or contradictory.