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. Obliques Many people put a lot of focus on working their abs but forget their surrounding neighbors; the oblique muscles. Obliques serve as stabilizers, and are used in almost every physical activity. Exercising your obliques should be a very important part of your workout program. Exercise Instructions Step 1 Start in a standing position with both hands at your side. Step 2 Bend forward and place your hands on the ground and walk out into a push-up plank position. Keep your back flat and your core engaged. Step 3 At the bottom of the walk out reach out with each hand making sure to keep a flat back and tight core.