To torch more calories than running a six-minute mile, you could cross-country ski uphill at a crazy-fast clip. Or you could swing a cast-iron kettlebell for 20 minutes to get the same sizzle, researchers from the University of Wisconsin La Crosse Exercise and Health Program conclude. To turn up the burn even more, we found a firm-up that melds the proven pound eraser with butt-kicking martial arts moves. Each energizing exercise in this mix sheds and sculpts, remaking your shape.
Russian-born Dasha Libin (her grandfather taught kettlebells to the Soviet army!), co-owner of Anderson Martial Arts in New York City, created this clever Kettlebell Kickboxing combo.
A 10- to 15-pound kettlebell ($30 and up; GoFit.net).
Warm up for five minutes (shadowbox, jump rope—you decide). Then do each three-move round, performing every exercise for one minute. Take a one-minute breather between rounds. Try the sizzle session three times a week on nonconsecutive days.
Stand with feet staggered, right leg in front, holding kettlebell horns at chest. Rotate torso to left as you bring left knee toward right elbow. Return to start. Repeat quickly on opposite side. Continue for one minute.
works abs, butt, thighs
Stand with feet hip-width apart, holding horns at chest. Lunge left leg back, raising arms overhead. Stand, kicking left leg forward as you lower arms to chest. Return to lunge. Continue for 30 seconds. Switch sides; repeat.
works shoulders, arms, back, abs, butt, thighs
Round1: Tip-top Toner
Stand on tiptoes, holding kettlebell upside down by horns at chest; squat. Stay on tiptoes and stand, straightening arms overhead, then lower kettlebell behind head until forearms are parallel to floor. Reverse movement to return to start. Continue for one minute
works arms, abs, butt, thighs, calves