10 Flat-Belly Tricks
Have a ball
"My No. 1 tip: Do the ball exchange three times a week. Lay flat on your back with your arms above your head and legs straight out. Start with a stability ball above your head in your hands. Bring the ball up above your chest as you bring your legs up to meet the ball and place it between your ankles. Bring the ball back down
to the floor with your legs and straighten your arms back out over your head.
Repeat the ball exchange 10 to 12 times, remembering to keep your lower back pressed into the floor as you do this move."
LaReine Chabut, author of Exercise Balls for Dummies