HOW: Place a folded towel on the ground in front of you. Position both of your big toes on the towel with the balls of your feet still on the ground. Use a wall for balance support as you keep your knees straight and raise your heels off of the ground with your toes pushing into the towel.
FEEL: You should feel a stretch in the bottom of your big toe and underneath your foot.
COMPENSATION: Keep your big toe on the towel, not all of your foot. Keep your knee straight when raising your heel.