This can be done on flat ground or off a surface. We recommend a surface such as a stair case because you get a better stretch at the bottom position.
If on stairs, position your fee shoulder width apart with heels hanging off stairs. All weight will be on toes and front of foot. Lower your body by bringing your heels towrads the ground. Go as far as you can and then press with the front of your feet to bring your body up. Go up as high as you can on your tip toes and then go back down.