Principle of post-isometric relaxation (PIR)
This method is thoroughly described and illustrated by Karel Lewit in his excellent but rare book Manipulative Therapy in Rehabilitation of the Locomotor System. It is used to decontract specific muscles and is very well suited to self-mobilization. Due to the fact that this technique uses the gravity for lengthening muscles, the risk of injury while carrying out the exercises is much more limited than when stretching, particularly against fixed elements (door, wall, etc.).
It is applicable to numerous muscles, provided that the exercises are well thought-through. The page on the logic behind exercises is hence particularly relevant.
The post-isometric relaxation exercises all have the same structure:
- Start in a stable posture, with the muscle to be treated lengthened without stretching, exhaling deeply;
- While inhaling (and sometimes looking up), bring the muscle against gravity to a shortened position, which is held for about 8-10 seconds. Keep your breath if inhalation does not last long enough;
- Slowly "let go" to the lengthened position (sometimes looking down) while exhaling deeply;
- Repeat 3-5 times.
You need to know the function of a muscle before being able to apply the technique to it. Wikipedia offers useful information on this topic, muscle by muscle.
Upper trapezius PIR
The upper trapezius, among other funtions, extends the neck, and raises the scapula (shoulder blades) together with the acromio-clavicular joint (junction between the clavicula and the shoulder blades). Therefore, the exercise starts in sitting, the head falling loose and the shoulders low (see below).
After having deeply exhaled, inhale while looking up, extending the neck and raising the shoulders. This shortens the upper trapezius. Looking up increases the depth of the inhalation.
Hold for 8-10 seconds and come back to the first position while exhaling and looking down. Repeat the cycle a few times.
Lower trapezius PIR / Latissimus dorsi
This exercise is done overhead, so should be done carefully if you suffer from compressions in the neck.
Start lying on the opposite side from the one that you would like to relax. The knees are flexed, the lower arm is relaxed and low, the head is supported on a small pillow while the arm is extended in direction of the head. Exhale deeply while looking downward (see below) and bringing your hand on the side to relax as far as possible.
Inhaling 8-10 seconds while looking up naturally brings the upper arm slightly upward and backward (i.e., slightly adducts the scapula and humerus). A small displacement is enough.
Repeat the cycle 3-5 times and try to feel how moving the arm back influences the stretch.
Pectoralis major PIR, sternal division
This exercise is carried out in lying on a couch, bench or bed, so that one arm can freely fall to the side. The first position is with the arm out of the couch, falling laterally, at 90° with the midline of the body (longitudinal axis). Bringing the other arm away from the body helps stability.
After having deeply exhaled, inhale slowly while raising the arm against gravity (still at 90° from the longitudinal axis), and keep this position 8-10 seconds.
Come back slowly but without tension to the first position while exhaling deeply (8-10 sec.) and repeat the cycle.
Pectoralis major PIR, clavicular division
This exercise is the same as the previous one, with the arm "upward" (shoulder flexed more than 180°, as below). Note that rotating the head to the other side helps to limit compressions in the neck.
Scalene muscles PIR
The scalene muscles are small neck muscles that are involved in thoracic outlet syndrome, in particular when a displacement of the second rib is observed.
The basic position is almost the same as for relaxing the lower trapezius: Lying on the opposite side as the one to be relaxed, both arms low and relaxed. However, the head is not supported by any pillow, but is naturally falling. Exhale deeply while looking downward.
Bring back the head towards a horizontal position while looking upward and inhaling during 8-10 seconds.
