Purpose: The hands over head curl-up is an underwater specific core exercise. This exercises forces core stability, which is essential during underwater kicking.

Directions: Lie on a Bosu ball or on the ground with your arms in streamline. Next, tighten your abdominals from your ribs to your pelvis, while relaxing your neck and shoulders, and then lift your chest towards the ceiling, not arching your low back or bending from the low back. KEEP YOUR LOW BACK STABLE WITH THE CORE ACTIVE. Lower yourself to the ground, keeping your core tight and returning controlled.

Perform for multiple 10 - 20 repetitions to improve core endurance.