Lie face up on floor, knees bent with feet on floor and neck straight. Grasp medicine ball and hold at chest level. In a controlled motion, keeping neck straight, curl upper body up. Contract abdominals fully without compromising form. While maintaining the controlled motion, return to starting position. Do not allow muscle to relax before next repetition. This exercise can also be done with a partner by tossing the ball to your partner on your way up and catching the ball from your partner on your return.
Here are a few suggested alternative exercises:Ab CrunchAb Crunch ObliquesBall Crunch TraditionalDouble CrunchDumbbell Side BendsLateral Bend with Barbell