Photo Credits: Top, Getty Images/eclipse_images; Steps 1-3, Steer Digital Media.
1. Lay flat on your back, with your feet just a few inches off the ground and your arms holding the medicine ball at your chest. Keeping your arms straight, raise the medicine ball over your shoulders to touch the ground above your head.
2. Still keeping your arms straight, engage your core and lift your legs to pass the medicine ball in between your feet.
3. Keeping the medicine ball firmly held between your feet, lower your legs to just a few inches above the floor. Don't let the ball touch the floor. Return the medicine ball back to your feet by reversing the motion from step 2.