Swiss balls are deceptive. Big, rubbery air-filled balls, they look soft and comfy, and they are—if all you do is sit on them. Employ them as part of your fitness routine, however, and you have a highly effective weapon in your battle against the bulge. The trick is to use their inherent instability to your advantage. As you work to stabilize yourself against the ball’s natural tendency to roll, you activate a host of muscles, both superficial ones and the deeper ones of the midsection, commonly referred to as the “core.”
The video above is an exclusive workout, compliments of Zero Belly Diet, the New York Times bestseller by David Zinczenko, co-author of Eat This, Not That! Its exercises worked for Krisa Kirk, a Zero Belly test panelist. Within two weeks of eating well and gaining core strength with Zero Belly circuits, Krista hips slimmed down and "I'd avoided wearing high heels because the extra weight made my knees hurt so bad," she says. "I can actually wear my heels with confidence and without pain!"
Repeat the circuit three times with two minutes of rest between circuits.