The Pulsed Push-Up
What it does: Strengthens the chest, shoulders, backs of arms, and abs; improves posture.
How to do it: Place your hands on a step stool, shoulder-width apart. Straighten your legs behind you, shoulders over your hands. Bend your elbows to lower your chest as far as you can. Hold the low position; pulse slightly higher and lower three times. Return to the high position.