When using a stability ball you must make sure the ball is the correct size for you. To determine this sit on the ball with your feet shoulder width apart. If your knees are at a 90 degree angle the ball is the right size for you and you are ready to start. To perform an abdominal crunch effectively on the ball, start by moving your hips forward and lying back onto the ball. Place your hands across your chest. Once in this position concentrate on raising your chest and shoulders up to a 45 degree angle. Now squeeze your abdominals and return to the starting position. Perform three sets of 15 to 20 repetitions. To increase the difficulty put your feet closer together. If you do not have access to a stability ball perform your crunches on an exercise mat.

Shaun Karp is a certified personal trainer in Vancouver. For further information call his office at 604-420-7800.