Medicine Ball V Sit-Ups

Set an adjustable bench at a 45-degree angle (or lie on the floor). Lie down with your head toward the floor and hook your feet at the top.

Hold a medicine ball at your chest as you lower yourself.
 
As you come up, chest-pass the ball straight up over your head or off a wall. Catch it at the top of the movement, then lower yourself and repeat.
 
If you do not have a medicine ball, use any ball, or just make the motion without a ball, being sure that you concentrate on proper form.