Post Isometric Relaxation or also known as PIR begins by having the muscle in a stretched position. Then, this is followed by the application of an isometric contraction against minimal resistance.
PIR is performed as follows:
- The hypertonic muscle is extended to the point where resistance to movement is first noted.
- A submaximal (10-20%) contraction of the hypertonic muscle is performed away from the barrier for between 5 and 10 seconds while the therapist applies resistance in the opposite direction.
- After the isometric contraction the patient relaxes and exhales while a gentle stretch is applied.
- The procedure is then repeated two or three times.
