Credit: Jonathan Pozniak

What it does: Works the backs of upper arms and the shoulders, abs, and fronts of thighs; improves balance.

How to do it: Sit on a step stool with your hands grasping the front edge. Place both heels on the floor, hip-distance apart, knees almost straight. Slowly lower your buttocks toward the floor by bending your elbows and lift your right leg. Press up with your arms as you lower your foot. Repeat, switching legs.