1. Lie back onto floor or bench with knees bent and hands behind head. Keep elbows back and out of sight. Head should be in a neutral position with a space between chin and chest.
2. Start position: Place a medicine ball between your knees.
3. Leading with the chin and chest towards the ceiling, contract the abdominals and raise shoulders off floor or bench. During the crunch, also bring knees towards chest.
4. Return to start position.
5. Remember to keep head and back in a neutral position. Hyperextension or flexion of either may cause injury.
