This butt-toning move comes from the Core Fusion: Thighs and Glutes DVD from Elisabeth Halfpapp and Fred DeVito, the duo behind the Exhale Core Fusion craze. The move may look simple, but trust us, you'll quickly feel the burn.

How to do it: Sit on your mat with the right knee bent directly in front of the right hip and left knee bent behind left hip. Place your fingertips on each side of the body, near the right knee, slightly wider than shoulders width apart. Engage the core muscles; raise the left knee and foot off floor. Lower it back down.

Do 20 reps, touching the floor with knee between reps. Then, keeping the knee up, press your knee back for 20 reps.

Switch legs; repeat both moves.

Trainer tip: If you're having too much trouble lifting your knee, just lift your foot off the floor.

Try this move: The Pretzel

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