Begin in an elbow plank with your elbows underneath your shoulders and a paper plate underneath each foot. Keep your core engaged and your back flat.
Pull both knees in toward your chest, then straighten your legs, maintaining a flat back and strong core. This counts as one rep.
Perform as many reps as you can with correct form in one minute, making sure to keep your shoulders pulled away from your ears. If this is too hard, pull one knee in toward your chest at a time.