Greg Louganis Diver's Crunches
1. Lying on your back on a swiss ball, feet shoulder width apart.
2. Overlap your hands and extend your arms straight backwards like a diver.
3. Crunch up using your abs until you are about 4-inches above 90-degrees, arms still extended over your head.
4. Hold 2-seconds - flex abs and lower yourself back down and repeat.