Lie on side with legs straight, one leg on top of the other. Place forearm under shoulder perpendicular to body.
Keeping side of bottom foot on ground, raise hips up off ground while raising upper leg upward away from lower leg. Return to original position and repeat. Continue with opposite leg.
Exercise can be performed with bent knees. Movement can also be made easier by leaning body up against wall, horizontal bar or platform.
Exercise can be made more challenging with ankle weight attached to upper ankle.