MUSCLES ENGAGED Triceps Triceps are an often forgotten muscle group. Triceps are located on the opposite side of the biceps at the back of the upper arm. Well strengthened and defined triceps make the arm look bigger and sleeker (reducing the "flabby arm" look). 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. Equipment Used Cable Machine The cable machine is a piece of equipment used in weight training or functional training. A wide variety of exercises can be performed using the apparatus. Exercise Instructions Step 1 Start by holding the handle in one hand with with your arm placed by your side, your shoulders pulled back and a slight bend in your knees. Step 2 Extend your arm and fully contract you tricep at the end of the motion. Step 3 Return your arm back to the starting position and repeat.