Get A Flat Belly - Stability Ball Pass
Exercise balls aren't just great to sit on – they can serve as an instability tool in other ways as well. Holding the ball between your legs as you lift and lower during your reps is more difficult than it looks,
and it causes you to contract your core involuntarily, leading to bigger gains.
Stability-Ball Pass – What it works: All of your major abs muscles are hit with this move, with particular emphasis on your upper and lower abs.
What to do:
Three sets of 15 reps