Begin in a high plank, your hands under your shoulders and heels over your toes. Pull your core towards your spine.
Keep your core engaged as you lower your right elbow to the mat, then your left, coming into an elbow plank.
Put your right hand on the mat, and straighten your right elbow. Do the same on the left to return to a full plank. Pull your core in throughout the movement and avoid hunching your back.