HOW: Start on your hands and your feet, have your hands positioned under your shoulders. Place one hand on a yoga block or something similar. To begin the exercise, assume a high plank position, while keeping your body straight lower your chest down towards the ground as far as you can, push up to the starting position and repeat.
FEEL: This should feel like an upper body workout, your shoulders, chest, and triceps. You should also feel your core and your glutes/quads working to maintain a straight body from your heels to the back of your head. It will feel harder on the side of the block.
COMPENSATION: Keep your body in a straight line, don't hike your hips high in the air or let your butt sag to the ground. Stay evenly balanced through both arms as you lower down and push up.