Start on all fours with hands underneath your shoulders and knees under your hips. Keeping the knee bent 90 degrees, lift the right leg until it is parallel to the floor.
Keep the right thigh still as you straighten your right knee, kicking your leg out to the side. Don't let the leg lower as you kick it.
Bend the right knee back to 90 degrees, and then lower the leg. This completes one rep.