MUSCLES ENGAGED Back (middle) Middle back muscles are very important as they help to support and strengthen the core muscles at the front of your body. 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 Dumbbells The dumbbell, a type of free weight, is a piece of equipment used in weight training. It can be used individually or in pairs (one for each hand). Dumbbells vary in weight from 3lbs. up to 150lbs. Exercise Instructions Step 1 Start in a push-up position with your feet shoulder width apart. Hold a dumbbell in each hand and and line your shoulders up right over top. Step 2 Pull the dumbbell up to your rib cage and then rotate over and press the dumbbell up towards the ceiling. Step 3 Lower the dumbbell back down to the starting position and repeat.