- Lie back on a Swiss ball with knees bent at a 90-degree angle and feet on the floor about shoulder-width apart.
- Interlace your fingers behind your head. The ball should be under your hips and lower back.
- Crunch your torso toward your knees, raising your chest upward.
- Stop when the middle of your back loses contact with the ball.
- Pause, then return to starting position.