Progressive relaxation is a way of releasing tension in muscles. A common technique is the following:
Lie on your back in a comfortable position. Take a series of deep slow breaths and focus your awareness on different parts of the body in turn, becoming aware of any muscular tension and releasing it. One way to do this is to first tense a muscle deliberately and then relax it. Start with the front of the body, tensing and relaxing the muscles of the upper face, then moving on to the jaw, neck, chest, front of the arms, abdomen, thighs, lower legs, feet and toes. Then, do the same down the back of the body. Finally, lie still with the eyes closed, concentrating on your breath and enjoying the feeling of peace and freedom from tension.