Leg Press Machine
Position yourself on a leg-press machine as you would to perform a normal leg press. Move your feet so that the balls of your feet are on the edge of the foot platform and your heels are unsupported. Remove the safety catches and keep your legs straight, knees almost locked. Keeping your heels fixed, let the weight push your toes back toward you and fully stretch the calves. At this point, press the weight back up with your toes as far as possible until your calf muscles are fully contracted. Hold this position for a moment and then slowly lower the weight back to the starting position. For variety, alternate pointing your toes inward, outward and straight forward.