Progressive Deep Muscle Relaxation
In this technique we also take advantage of the mind-body connection. We will teach you to contract and relax various muscles progressively allowing you to enjoy the difference between the tense sensations in the muscle and the relaxed sensations that come after you have let the tension go
Since its description by Jacobson in 1938 this technique has a record of proven efficacy. There is a 2007 review of the literature that summarises all the available evidence up to that date which you can find here.