Progressive Muscle Relaxation (PMR) – what exactly is it?
Progressive muscle relaxation is a relaxation procedure according to Edmund Jacobson (1888-1983), who published the original method of the procedure in 1938. His basic assumption was that there is a close interaction between physical and mental tension. Jacobson observed that muscle tension immediately increased in states of stress, restlessness, or anxiety. From this he concluded that a state of mental or psychological relaxation can also be achieved in reverse by relaxing the muscles. 
Progressive Muscle Relaxation (PMR) therefore induces a relaxation reaction through the stepwise (progressive) conscious tensing and relaxing of different muscle groups. Since the first version in 1938, the relaxation procedure has been revised several times by various authors. One of the most frequently used versions today is based on the Bernstein and Borkovec revisions. [2,3]
How is PMR carried out?
Progressive muscle relaxation can be performed while lying down or sitting down. At the beginning it is usually easier to start with a lying position because this is the quickest way to achieve a relaxed state. During the course of the exercise, you should also try the exercises in a sitting position in order to be able to integrate them more easily into everyday life later on.
The exercise instructions are usually given by a therapist, but you can also use sound recordings to practice independently at home.
The exercises are often started with a small special introduction, the so-called relaxation induction. The practitioner is asked to turn his attention inwards, close his eyes and calm down with a few deep breaths. Then the gradual tensing and relaxation of the muscle groups begins. 
The course of the exercises is as follows:
Focus attention on a specific muscle group
- Tensing the muscle group according to a sign from the therapist
- Holding the tension for approx. 5 to 10 seconds
- Loosening the tension of the muscle group to another sign
- Focusing on the muscle group for 20-30 seconds to perceive the difference between tension and relaxation
In the long version of Progressive Muscle Relaxation, the following 16 groups of muscles are dealt with one after another:
- Dominant hand and forearm (e.g. for left-handed people the left side)
- Dominant upper arm
- Non-dominant hand and forearm (e.g. for left-handers the right side)
- Non-dominant upper arm
- Upper cheek area and nose
- Lower cheek area and jaws
- Neck and throat
- Chest, shoulders and upper back
- Dominant thigh
- Dominant lower leg
- Dominant Foot
- Non-dominant thigh
- Non-dominant lower leg
- Non-dominant foot
After all muscle groups have been exercised, the individual muscles are consciously perceived one after the other in order to determine whether tension can still be felt. This is usually followed by a 2-3 minute rest period. The PMR often ends with a return phase. It is counted from 4 to 1, first the legs are moved and activated at 4, at 3 the arms, at 2 the trunk and at 1 the eyes are opened again. The entire process takes about 20 minutes. 
The 16 muscle groups from the long version can also be combined, so there are shorter versions with 7 or 4 muscle groups. Here, for example, both hands and forearms are tensed simultaneously. Usually you start with the long version and then the length of the exercises is reduced, but you can also start with the short versions. The short versions have the advantage that they can be integrated more easily into everyday life. Here often 5-10 minutes are sufficient. 
What do I have to consider when practicing?
- Ideally practice about 2 times a day for a few minutes. Set a schedule!
- The first effects are usually only noticeable after 2 weeks of daily practice. Stay with it!
- Start by practicing in a quiet room and try to eliminate all sources of interference as best you can.
- Keep to the order of the muscle groups and the same sequence of exercises if possible, this simplifies the learning process.
- Practice in calm or relaxed situations at the beginning. It will help you to find your way into the relaxation exercises, especially at the beginning.
- No painful sensations should be caused during the tension phase. Existing pain should not be increased by the force of tension. Therefore, be careful not to cramp when tightening, a slight tightening is sufficient!
What is the long-term effect of progressive muscle relaxation?
Regular exercise improves general body perception. The difference between tense and relaxed musculature will become more and more noticeable in the course of training. Tightened or tense muscles can be detected early. Muscle tension can be deliberately reduced. The subjective experience of relaxation is also deepened during the course of the training.
It is easier to relax and you will be able to change from a state of tension or restlessness to a relaxed state more quickly. Over time you will develop a more relaxed attitude towards everyday stress and other burdens. 
Stressful factors such as excessive demands, fears or pain lead to involuntary tension in individual muscle groups. Progressive muscle relaxation is one of the most important relaxation methods to break this cycle. The effectiveness of the procedure has been confirmed in numerous scientific studies. Progressive muscle relaxation is used in many different fields of treatment, including multimodal pain therapy for chronical backpain deseases.