Using a ball lie on your stomach with your inner core engaged by pulling the waistline up from the pant line. Keep the core engaged the entire time. Start with bringing the elbow up so the arm is at 90 degrees with the fist clenched. Keeping the upper arm and wrist still bring the forearm up parallel to the floor and back down slightly. Repeat this for 30 seconds 3 sets twice daily. This exercise is great for retraining the motor control of the scapular muscles in conjunction with core stability strengthening. Excellent to do in the strengthening rehabilitation phases of any kind of shoulder injury. Great for swimmers, baseball, tennis, volleyball, basketball or ultimate players.