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. 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). Equipment Used Barbell A barbell is a piece of exercise equipment used in weight training, weightlifting and powerlifting. Barbells range in length from 4 feet (1.2 m) to 8 feet (2.4 m) and vary in diameter. Exercise Instructions Step 1 Start in a standing position while holding the barbell just above your collar bone. Step 2 Engage your glutes and press the bar over your head. Keep the bar as close to you as you can and press it directly over your head. Step 3 Lower the bar back down to the starting position just above your collar bone and repeat.