In order to solve the problem of stiff and thick deltoid muscle, yoga deltoid muscle makes up for its brawniness. People can often do these six effective exercises, stretching deltoid muscle before and after practice, avoiding stiff and thick deltoid muscle, and at the same time dredging shoulder neck and opening shoulders. 1. Stand in the mountain, hands in front of you, palms facing each other. 2. Kneel on the mat, with your legs as wide as your hips. 3. Lie on the mat and raise your arms horizontally. 4. Stand on the mountain with your feet hip width apart. 5. Open your arms to both sides and bend your arms against the wall. 6. Kneel or sit on a yoga brick.