This toughie exercise from Alison Sweeney, host of The Biggest Loser, works the entire body while promoting agility and coordination.
Here's how to do it: Start in the "up" part of a push-up position, with your shoulders over your wrists, body in a straight line from head to toe and feet hip-width apart. Rotate your torso to right, putting weight on your left hand, and lift your right arm up as you raise your core and pull your left leg through and extend it out to 45 degrees, placing right foot on ground for support. Hold for 2 seconds, then return to start. Repeat on opposite side. Do 8 to 10 reps on each side.
Tip: You should be looking up, along your raised arm.
Try this move: Sit Out