Postisometric relaxation (PIR) combines manual medicine and self-rehabilitation. It is a technique that treats muscle spasms and overloaded muscle fibers, especially trigger points. It can improve pain and prepare the muscles for subsequent physical activity. PIR achieves muscle tension, which is suitable for coordination-intensive movement patterns. By adjusting the tension of one muscle, we also affect the tension of all the muscles that make up the functional chain. Therefore, it is possible to treat chained muscle spasms and trigger points provoking the transferred pain with this method. The advantage of PIR is that patients can perform it themselves at home and so it helps to promote self-efficacy.
First, we will examine the ranges of active movement in the segments on which we will focus the therapy. We can palpate muscle tone and trigger points.
At the beginning of the therapy, we aim to achieve the greatest possible stretch of the muscle fibres on which we act – the so-called prestressing. At the same time, we do not stretch the muscle and do not push through the pain.
In this prestressed position, the patient applies resistance to stretching the muscle with minimal force (isometrically) for about 10 s, while holding their inhaled breath. The patient is then asked to "relax", which is associated with exhalation of the patient and relaxation of the pre-activated muscle. With relaxation the muscle is stretched by de-contraction (not passive stretching). The therapist waits for the patient to truly relax as long as he feels that the muscle is relaxing, and then another prestress is applied.
The relaxation period can last up to three times longer than the contraction time. If relaxation is insufficient and difficult for the patient, the isometric phase is prolonged and vice versa. The process is repeated as necessary. The prestress should not be in a position of shorter muscle length than achieved during the previous relaxation.
For each muscle, there is a given position method in which to apply PIR. For some muscles it is possible for the patient to treat themselves.
PIR can be improved through various physiological functions. These include, for example, inhalation and exhalation, which inhibit and facilitate the trunk muscles depending on breathing. Another such element is facilitation by sight. Some muscles are facilitated by looking up (e.g. head and neck extenders), others by looking down (e.g. head and neck flexors). Gravity can also be used as part of antigravity relaxation for example in self treatment.
Examples of use in general rehabilitation
Using PIR, suitable terrain is made to allow for further therapy. So PIR is performed before mobilization, reciprocal inhibition, etc to facilitate and improve the quality of movement.
The most common mistakes of the therapist
Correction of the patient's breathing stereotype is inappropriate, the patient should breathe in his own rhythm, and the therapist adapts to it.
Too much resistance, where the therapist tries to facilitate the muscle. We only want to activate the most overloaded muscle fibres through minimal force; with too much resistance from the therapist, more fibres are activated and the PIR is not as effective.
Poor relaxation of the patient is also an obstacle to therapy, as it makes de-contraction more difficult. The therapist must pay attention to the patient's ability to relax and adjust the isometric phase accordingly, or use another technique to influence muscle tension. With decontraction, the therapist does not stretch the muscle fibre, only followed by relaxation and relaxation of the patient.