Progressive Muscle Relaxation (PMR) is a technique developed by physician Edmund Jacobson in the 1920s in which you systematically tense and then release muscle groups throughout the body, moving progressively from feet to head. The contrast between tension and release trains the body's awareness of physical stress and the capacity to voluntarily release it. PMR is widely used for insomnia, anxiety, headaches, and chronic pain, and is often taught as a complement to breath-based meditation for people who carry significant physical tension. Research confirms its efficacy for anxiety reduction comparable to other relaxation techniques.

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Wikipedia: Progressive Muscle Relaxation

https://en.wikipedia.org/wiki/Progressive_muscle_relaxation