The Achilles Fitness Donkey Calf Raise attachement is the world' 1st Calf Raise attachment for the Smith Machine, This Patented commercial fitness apparatus is Ergonomically designed to allow the user to mainly activate the gastrocnemius calf muscle when the knee is straight. This training method applies stress and elongation of the muscles of the hip, knee and ankle joint thus generating greater power. The Donkey Calf Raise is the most effective exercise for strengthening and building the calf muscle. It is a great isolation movement for overall calf development and calf mass and is simply one of the best exercises for developing the calves.