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Yes, she's a supermodel, but Heidi Klum still hits the gym to work those stems. Her go-to move: the Sumo Lunge. "It shapes and tones without building bulk," says her trainer, David Kirsch. Do 15 reps per side 4 times a week to get firmer in a month.

Stand with feet shoulder-width apart, slight bend in knees, abs tight (A). Lift and extend right leg (thigh parallel to floor); kick up and over to right in half-moon shape (B).
Land with legs wider than at start; lower into squat (C). Stand; raise right leg, bring knee to chest, and rotate hips and right leg up; kick out to the side, foot flexed (D). Return to start.


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