MUSCLES ENGAGED Shoulders The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well. Abdominals The abdominal muscles (abs) provide movement and support to your core area. The deeper and closer to the spine the particular abdominal muscle is, the more effect over body posture it will have, and this often contributes significantly to a healthy back. Exercise Instructions Step 1 Place your hands on the floor several inches away from the wall and a little wider than your shoulders. Step 2 Kick up and place your heels against the wall. Step 3 Keep your body nice and straight and maintain the hand stand for as long as you can keep good form.