AB CRUNCH:

1. Sit on the ball with your knees and legs slightly apart.

2. Come into a reclining position by walking your feet forward.

3. Cross your arms in front of your chest or put them behind your head.

4. Exhale and lift your head and chest until your shoulder blades lift off the ball.

(see Figure 2)

5. Hold the position for a few seconds. Inhale and slowly  return to the reclining position.