Knees To Chest

Start:  Lie on your back on a flat bench or floor.  Grasp the bench (stable object if you are on the floor) with both hands overhead.  Place a small stability ball underneath your legs.

Movement:  Squeeze the ball with your legs.  Contract your abs and curl your hips and low back off the bench/floor bringing your knees towards your chest.

Finish:  Hips and low back are off the bench/floor.  When you return to the starting position do not let the ball touch the bench/floor.