Elbow Plank An elbow plank should only be performed if you can successfully engage your abs in a side plank. Start face down on the floor, resting on your forearms and knees. Push off the floor, raising up off your knees onto your toes and resting mainly on your elbows. Contract your abdominals to keep yourself up and prevent your booty from sticking up. Keep your back flat — don't let it droop or you'll be defeating the purpose. Picture your body as a long straight board or plank. Hold for 10 seconds. This completes one rep. Do one set of three reps. As you get stronger, begin to build up to 30 seconds. Image Source: POPSUGAR Photography