To do Plank Skier Hops, start in the plank position with your hands under your shoulders and your legs together. Your body should be in a nice straight line from your head to your heels.
Then, with your legs together, jump your feet in toward your right elbow, rotating so that your knees come outside your elbow. Jump back into the plank position with your feet back center and your body in a nice straight line.
Then jump your feet back in, but this time toward your opposite elbow. Rotate to bring your knees toward the outside of your elbow. Jump your feet back out center.
Do not let your body shift backward as you perform the hops and jump back out. Try to keep your chest over your hands instead of letting your hands get way up by your head.
Keep alternating hops toward each elbow.