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 push-up plank position with your feet shoulder width apart and your back flat. Step 2 Brace yourself in a 3 point plank position and then lift one arm off the floor and touch the opposite shoulder. Step 3 Lower your arm to the floor, switch sides and repeat.