O-Ring is also known as the Omura bi-digital O-ring test. The main limitations:
Having the practitioner, an assistant, and a patient positioned within the immediate area of each other’s body field leads inevitably to energetic “contamination” between the (three) parties involved. This may result in false-positive or false-negative results.
Application of force
This limitation is clearly spelled out by the authors themselves in their application for the U.S. Patent:
“However, the O-ring test is conducted by using the fingers of the hand which is the voluntary muscle controlled at will by a person, so that there is a possibility that indeterminate factors may appear.
“For example, the cases may occur in which the subject forming the O-ring shape with two fingers and the examiner attempting to pull the O-ring shape apart participate in the O-ring test by using different finger strengths due to the difference in their respective wills.
“In addition, the voluntary muscle tends to be fatigued easily and, in some cases, the muscle strength of the voluntary muscle may be increased or decreased consciously. Therefore, the cases may occur in which the O-ring test cannot be performed accurately and objectively.”
(see U.S. Patent No. 5, 913, 835 and Leisman, Gerald, Zenhausern, Robert, Electromyographic Effects of Fatigue and Task Repetition on the Validity of Estimates of Strong and Weak Muscles in Applied Kinesiological Muscle-Testing Procedures, Perceptual and Motor Skills, 1995, 80, 963-977).
The Diagnostic and Therapeutic commentary is the same as presented on Applied Kinesiology.