Place the ball of one foot on the edge of a block or stair. Wrap the other foot behind the lower leg that is positioned on the block. All weight should be on the standing foot. Use a support for balance and slowly lower the heel of the working leg as low as possible; then rise up on the toe until the calf is fully flexed. Lower and repeat. This exercise maybe varied by holding a dumbbell in the hand on the same side of the working leg.