Start in full plank position with your hands directly below your shoulders, abs in tight. Lower your body until your chest is just a few inches above the floor. Press halfway up, then lower back to hover above from the floor. Press all the way back up to full plank. That's one rep.
Do 10 in a row with proper form, being careful not to let your hips sag or your back arch during the movement. Drop to your knees if it's too challenging.