Jillian Michaels, the trainer from NBC's The Biggest Loser and self-proclaimed "TV's toughest fitness guru," runs through circuit training like a drill sergeant on caffeine. Her theory is to keep moving in between exercises to burn twice as many calories, so she cycles her team through sumo squats, mountain climbers, jump ropes, shoulder raises and bicycle moves without taking a breath. If she doesn't think one of her comrades is picking up his knees high enough, she makes everyone do 30 more, with a sadistic grin. As a result, you can almost literally watch the muscle burn. Michaels' Shape-Up Front DVD works out the chest, shoulders, triceps and quads. It also requires two props: a bench-style exercise step and light dumbbells. The DVD features include printable diet/exercise logs, nutrition tips and recipes. Despite a lower-level option, it isn't for anyone looking for a low-impact aerobic workout.

Shape-Up Backside

Look no further than Michaels's Shape-Up Backside exercise DVD for an intense high-impact workout. Michaels keeps your body moving (though she herself skips out on half the exercises) with hammer curls, oblique raises, step ups, planks, and a move called The Superman destined to tone your back, biceps glutes, hamstrings and abs. There's a lower-level option, but Michaels likes to "kick your butt," as she says, to get you to feel the burn. Shape-Up Backside's DVD features include printable diet/exercise logs, nutrition tips and recipes. It requires two props: a bench-style exercise step and light dumbbells, which may make it difficult for beginners. But if you give it a try, even in the comfort of your living room you'll think you're in a gym -- trainer yelling in your ear and all. -- Ellen A. Kim

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