Applied kinesiology finds its roots in  observations made in 1964 by Dr. George J. Goodheart, Jr, a chiropractic physician, then practicing in Detroit, Michigan.  Goodheart's observations regarding muscle balance, muscle strength and muscle weakness refuted the then held theory that muscle spasm was the primary cause of back pain.  According to Goodheart, the primary cause of back pain is muscle weakness.  Muscle weakness (as observed by manual testing) was soon to be understood as an inhibition of motor neurons located in the spinal cord's anterior horn motor neuron pool.

Weakness (inhibition) of any muscle, Goodheart observes, causes the contralateral, antagonistic or opposing muscles to contract, thereby causing pain.  When a muscle contracts without the normal antagonistic response, it isn't the tight or contracted muscle that needs help, it is the weak (inhibited) muscle that needs to be strengthened (facilitated), thereby restoring muscle balance and relieving secondary muscle spasm.  A real case of primary muscle spasm is, in reality, seldom seen.  It is, rather, a secondary condition.

Applied kinesiology allows the doctor to diagnose, through the use of the manual muscle testing response, the need for the application of a variety of sensory receptor based therapies that, when appropriately applied, result in improved neurological function.  This "new system of diagnosis" confirms that when the need is diagnosed and appropriate therapy is supplied, the results are often remarkable.