HOW: Get set-up in a quadruped position on your hands and knees. Start strong in your shoulder blades by pushing your body away from the floor. From here you will lift one leg off the floor and drive your knee out to the side and back while keeping your knee bent at 90 degrees. This motion is driven by the hip.
FEEL: You should feel this exercise in your hip muscles, particularly your butt (glute) muscles of the leg that is moving.
COMPENSATION: Avoid rotating your entire trunk with this exercise, avoid arching your back, do not bend or straighten your knee, maintain knee position.