Exercise Advice: Start off with a very light medicine ball to get the form of the movement down. While Laying down on an exercise mat, securely hold a medicine ball over your head and stretch out your arms and legs. Crunch upwards keeping your arms straight and raise your feet to your hands. Slowly place the medicine ball in between your feet and lower your body into the starting position while keeping your feet just off the ground and the medicine ball between your feet. Crunch back up, raise your legs and grab the medicine ball from your feet. Finally, lower your legs and upper body to the starting position. This is a very tough ab exercise, so make sure to start off very light and focus on perfect form.