This is an upper-body explosive, ballistic exercise.
1. Hold a medicine ball in front of your chest with your arms extended and stand with your side about three feet from a wall. Your feet should be a little wider than shoulder width apart.
2. Bring the ball across your body, quickly rotate your torso to throw the ball against the wall. Catch the ball on the rebound and return to the starting position.
3. Alternately, you can use a partner. Be sure to stay firmly planted so that your torso does the work.