Get into a high plank position. Bring your right knee towards your left elbow, then your left knee towards your right elbow, alternating quickly. Lie on your back with hands behind your head.

From a high plank position, lower your body one inch ... Immediately do 6 mountain climbers, alternating sides, with left knee meeting left elbow followed by right knee to right elbow.

Start in a high plank position with your shoulders over your wrists and your body straight. Bring one knee toward the opposite elbow, then return to the plank position. Alternate sides ...