1.  Start Position Exhale as you slowly crunch, by raising your legs toward your chest. Keep your legs at a 90-degree angle and the ball stabilized. 
2.  Middle Position Concentrate on using your abdominals, while maintaining the tennis-ball-sized gap between your chin and your chest. Keep your grip secure and your arms stationary. 
3. End Position Continue to lift your legs, bringing them as close to your chest as possible, without letting the small of your back leave the ball. Hold for 1/2 a second, squeezing your abdominals. 
4. Return to Middle Inhale as you slowly return to the starting position 
5. Return to Start The small of your back remains in contact with the ball. Repeat the movement for the recommended number fo repetitions.

Start at this Position: 

•  Note: This is an advanced level exercise requiring exceptional abdominal strength. You should not perform this exercise if you have any lower back, neck, or shoulder problems. If you feel any pain, STOP IMMEDIATELY!
• Locate a stationary piece of equipment in an open area. Place the stability ball near the equipment, a little closer than arm's distance away.
• Sit on the ball. Lie with your back on the ball, positioning your feet flat on the floor. Bring your hands behind your head, and securely grip the equipment, keeping your elbows bent. Lift your head to create a tennis-ball-sized gap between your chin and chest. Cross your ankles.
• Position your body so the small of your back becomes the center of gravity on the ball. If you feel discomfort in your lower back, DO NOT PERFORM THIS EXERCISE.
•  Note: To increase the challenge, move your glute further down the ball.
• Raise your legs to a 90-degree angle. If you fell pain in your back, bring your feet higher, but be sure to ALWAYS keep your feet lower than your upper body. If this does not alleviate the discomfort in your lower back then DO NOT PERFORM THIS EXERCISE.
• Keep the small of your back in contact with the ball and your head aligned with your spine.

1. Throughout the entire range of motion:

   • Keep your head aligned with your spine.
   • Keep your chin aligned with the middle of your chest.
   • Concentrate on using your abdominals, keeping your grip secure and your arms stationary.
   • Keep your legs bent at a 90-degree angle.
   • Keep the ball stabilized. If any movement of the ball occurs, STOP reposition your body; then continue.

2. At start and end positions, be sure to keep the small of your back in contact with the ball to alleviate unnecessary stress on your back.