A very effective exercise to strengthen abdominal muscles.
- Lay stretched out on your back on a gym mat or on the floor with the ball under your calves. Loop the exercise band around a table or chair leg (or something else sturdy that won't move) and hold the ends of the band with arms almost straight over your head.
- Bring your elbows in to your sides, then lift your shoulders and head slightly off the mat. Hold for a few seconds, then lower. Make sure you don't hold your breath.
Do 10 - 12 repetitions of the exercise. Rest briefly. Repeat for 1 or 2 more sets.