Stand upright on a stair (or any slightly elevated surface). This is the starting position.
2. Slowly flex your ankles to lower your heels (This is the bottom of the rep).
3. Once your heels touched the ground (Or you felt you can’t flex your ankles anymore), raise your heels as much as you can by squeezing your calves (This is the top of the rep).
4. Constantly move your heels between these two points until fatigue.
Working muscle/muscles:
