This move takes the belly-firming benefit of a Pilates V-sit and turns it into a total-core challenge. "Because you're dropping your legs from side to side, you're using all your midsection muscles--including the obliques at the sides of your waist," says Mindy Mylrea, who created this move for her All About Abs DVD (19.95; collagevideo.com). Keep your chest lifted and abs pulled in tight to prevent back strain and ensure that the emphasis stays on your core.
Workout Details: Do 2 sets of 15 to 20 reps as part of your regular routine. Beginners,
keep your feet on the floor.
Make It Harder: Instead of passing the ball, toss it from one hand to the other, or extend your legs.