Stand in front of a wall holding a 20-pound medicine ball with both hands at your chest. Set your feet at shoulder width with toes turned slightly out. Squat down until your hips are below your knees, keeping your lower back flat.
Explosively come up and throw the ball upward and against the wall, aiming for a spot about 10 feet up. Catch the ball as it comes down and immediately begin the next squat.