FitCeleb Katherine Heigl has a lean, svelte physique. When she heard that trainer Missy Beaver was teaching kettleball classes on the set of Grey's Anatomy, she signed up for one-on-one sessions to tone up all over. After a few weeks, Katherine's arms were more defined, her legs looked leaner, and her abs were firmer.

Find out how: Katherine's Workout: Three times a week, Katherine does a half-hour session with Beaver that targets all her muscles and burns more calories than regular weight lifting. She warms up with 10 minutes of easy cardio, then performs 6 to 8 sets of exercise with kettlebells (heavy,cannonball-like weights).

"I change the moves every time we train," says Beaver.

"It keeps her muscles challenged so she'll continue to see results." Her Anytime Exercise: When katherine can't eke out a full routine, she'll do a set of 10 kettlebell swings-swinging the weight back and forth- to get her heart rate up. Her Most Challenging Sculptor: "

She groans when it's time for the windmill," Beaver says.

"But Katherine loves how defined it makes her look." Try it!:

Stand with feet slightly wider than shoulders and hold the handle of a 5-to-10 pound kettleball in right hand next to right shoulder, so weight is resting on forearm. Squat and rise up quickly, pressing weight overhead. Turn feet 45 degrees to the left. Keeping eyes on kettlebell and right arm straight up, bend from the hips to touch left hand to left heel. Tighten abs to return to starting position, keeping right arm locked. Do 5 touches; switch sides to complete set.

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