A development leg exercise for your calf muscles.

Stand with a chair in front of you, its back-rest towards you, with your feet close together. Placing your hands on the back of the chair for balance only - make sure you don't support any of your weight on your hands.  Maintain the Neutral Spine Position and keep your upper body steady and your head up.

Balance your body weight over the ball of one foot and raise the other foot slightly, behind you. Use your core muscles to keep your hips level to the floor, do not raise the hip on the same side as the foot you have lifted.

Keeping your standing leg straight, lift yourself up by raising your heel. Hold for a second or two, and then lower your heel to the ground.