PIR is a very effective method that is used to relax muscles and is one of the physiotherapeutic techniques wich is used in manual medicine in order to prepare muscles for mobilisation- manipulation.

It is based on weaker isometric contraction of the aimed muscle by using the weaker resistance of the therapist. That is proceded with elongation of the painfull and stressed muscle. Since we decrease tension of the wanted muscles, we use this technique before treatment of mobilisation-manipulation. Sometimes, PIR is sufficient as treatment. The advantage of this technique is that by using minimal strengh of the patients muscle we do not cause pain.We also use it when treating the ancle because its decreased mobility is partially caused by the muscle spasm.Using facilitation reflexes of breathing and sight, the effects of muscle relaxation can be increased. If the aimed muscle and his fascia are shortened, they act like «bridles» and order the mobility of the ancle. With the musculo-fascial relaxation effect we automatically eliminate one factor which can diminish our manipulative effect and turn our ancle back into the pathologic position, respectivelly. How can we estimate the effecte of our treatment? Not only painfull treager spotts of our muscles disapear but also painfull ones at the connection of tendon to periost.

PIR is technique used not only by therapist but also as a selftreatment.When we compare PIR with the classical Kabatha method which is used in PNF, the resistance of therapist is much weaker, muscle contraction is 30% percent of muscle strengh, but it avoids active, forced stretching. Usually, in an acute phase we just use gravity force as the resistance, and after the pain is diminished the minimum of force.
The explanation of good results of this method are the following:

1. When using the minimal force resistance only the small number of muscle fibres are active; the others are inhibited.

2. During relaxation the stretching effect is avoided.

On the other hand there are cases when patient feels pain during PIR (ligament pain) but inspite of it he relaxes and after the procedure he experiences analgesia. This method clearly demonstrates the connection between pain and tension with relaxation and analgesion.
Shortened muscle can cause pain and ineffectivnes during the treatment because they can unable the poisture of overweight. If we procede manipulation without previously returning the muscle in his ideal poisture, it will during the next loading cause functional blockage of the ancle.