Muscle testing is a biofeedback mechanism that gives the practitioner information about what is a problem for the patient or may be helpful for the patient.
Muscle Testing and the Nervous System
The part of the nervous system that muscle testing is connected to is the autonomic nervous system. This is a division of the peripheral nervous system, and largely regulates the involuntary or unconscious actions of the body.
Some of the unconscious actions that the autonomic nervous system controls are heart rate, digestion, respiratory rate, and pupillary response. Muscle control is involuntary and voluntary. The muscle response in applied kinesiological muscle testing is actually an involuntary response. In other words the patient does not have control of the response.
An example of an involuntary response by the body would be if a person goes into a dark room and the pupils dilate, this is a response to a stimulus outside of the body that a person does not have control of.
In muscle testing, a substance may be placed by a specific acupuncture point, and the muscle responds involuntarily. This is based on the premise that it is either stressing the nervous system or it is helpful to the body.