Grab a chair (preferably a tall chair) and face it away from you. Stand an arms-length behind the chair with your feet together and grab the back of the seat with both hands for balance. Lean forward slightly and lift your right leg directly behind you, keeping your knee straight but not locked. Squeeze your glutes and make sure to square your hips with the chair; don't open your hip out to the side when you kick behind. Raise your leg as high as you can and then lower your leg with control and return to the starting position. Repeat this move 10 times and switch legs. Do two sets of these.