The Plank Pose
Come to the top of a push-up, palms spread wide, directly beneath the shoulders. Heels pressing back. Sit bones aim towards your heels. Belly lifted upward towards the spine. Press down through the palms, in order to keep the arms straight. Be careful not to sway the lower back. If this begins to happen, drop the knees to the floor.
Rev It Up: Add Push-Ups
Hugging the elbows in to the sides, slowly lower yourself down so that your chest is a couple of inches from the floor, and your triceps are parallel to the floor. Press back to Plank, again keeping your elbows close to the body.