Lie on side with head resting on the forearm. Hips and shoulders should face forward with spine in neutral position. Straighten bottom leg, then bend and cross top leg over it. Slowly lift the bottom leg as high as possible. Pause, return to starting position and repeat.
Tip: Throughout the exercise, keep upper foot flexed and pointing your toes straight out. When ready for more resistance, place a flex band over your bottom left foot while holding the other end with your balance hand. Repeat motion.