Swiss-Ball Side Crunch
Sets: 3-4 Reps: 4-6 Rest: 90 Seconds
Lie on your side on a Swiss ball and place your hands behind your head . Contract your abs and bend your torso as high as you can . Reverse the motion to return to the starting position. Be sure not to tuck your chin during the movement. That's one rep. Complete all your reps on that side, then switch sides and repeat. Brace your feet against a wall or bench for support.