This exercise focuses on lateral hip strength and gluteal strength. Initially you'll do this exercise using a wall for support and feedback. Start by lying on your side with your back, buttocks, shoulders, head and soles of feet up against a wall.Lift your top knee off of the bottom knee, while keeping the feet together. Lift only as high as you are able to without letting your pelvis roll back. The eventual goal is to be solid enough with your form to do this exercise without the wall for support but it's important for you to keep your pelvis stable and not roll your torso back as you lift your leg.
When you're ready for a progression you can use a resistance band around your legs just above your knees. Repeat as directed by your coach.