Crunch on Bosu Ball

Instructions

1. Place a BOSU ball flat-side down and sit on the dome, then lean back so your lower back is supported by the curve.
2. Cross your arms over your chest or place your hands behind your head.
3. Contract your abs to curl your upper torso forward and upward.
4. Lower back down slowly, allowing your spine to extend over the dome, and repeat for the desired reps.