According to Osho, the Hatha Yoga practice of tensing and releasing muscles is only a mechanical aid; effort is inimical to real relaxation. At most it relaxes the body superficially. True relaxation is existential: it happens when the doer is absent through understanding tension and being in the body. Dynamic Meditation uses activity only as a device to ignite awareness; the real shift is non-doing and the body’s own wisdom relaxing itself.
Squeezing and letting go may help a bit, but real rest comes when you stop trying, feel your body from inside, and let it relax by itself.