Postisometric Relaxation (PIR) is a physiotherapeutic technique to relax reflectorically tense muscles. After a trauma, i.e. an injury, but also after an operation, our muscles want to protect the affected area by increasing their tone, i.e. their tension, and by reducing their ability to move in the affected area.
It is often important to ensure early mobilization and to promote mobility in the injured area. To achieve this, Postisometric Relaxation (PIR) can relax the hypertonic muscles and increase the range of motion. The technique is based on the assumption that after a muscle has been isometrically tensed, it loses its tone in a relaxation phase and the range of motion is increased.
Postisometric Relaxation (PIR) can be performed by the patient alone for certain muscle groups. Usually, however, a therapist is required to set appropriate resistances and commands. The technique is particularly suitable for early mobilization when there is still a protective voltage. Due to the isometric tension, even small movement amplitudes can be worked out. It must be ensured that the isometric muscle tension takes place against a resistance and thus the injured structure must be sufficiently stabilized!
Implementation
The implementation of postisometric relaxation is relatively simple. The patient should always be in a comfortable starting position in which he/she feels as little or no pain as possible. A sore muscle will inevitably build up further protective tension and is therefore counterproductive for the success of the exercise.
The exercise is started from a position in which the patient has his current end of movement but does not yet feel any pain. At this point, the therapist sets a resistance at the muscle to be relaxed and asks the patient to tense against the resistance without any movement. The tensing of a muscle at a constant length – without movement – is called isometric.
The tension is held for about 5-10 seconds and then the therapist asks the patient to release the tension and relax the muscle. During the relaxation phase, the therapist can now passively extend the range of movement into the stretching of the muscle to be relaxed. If there is counter-tension or pain, the new range of motion is reached.
A further session can be started. If no further range of motion can be worked out after several sessions, the newly acquired position should be stabilized. If possible, this is done by tensing the opponent of the muscle to be detonated. The tensing can also be isometric/concentric by placing a resistance in the stretching direction, or eccentric. The opponent tenses and should only be pushed out of the new position very slowly – eccentric muscle activity describes the slow, controlled lengthening of a muscle.
