1. Start with your mid-back centered on the ball and your neck and shoulders hanging over the edge of the ball. You will have to squeeze your abs tight to hold this position. Open your feet shoulder-width apart and place your hands behind your head with your elbows open wide.
2. Squeeze your abs tight and push your lower back into the ball as you contract your abs to lift your shoulders up towards the ceiling. Continue to lift your shoulders, rounding your spine into the shape of the letter C. Squeeze your stomach tight and slowly resist back to the start position.