Jump 99 Strength Plyometric Shoes (11.5);

In regular shoes, 70% of the body's weight rest on the heel. Therefore, the calf muscles, exert little effort in supporting the body. In the new Jump 99 shies, the heel factor is eliminated, causing the calves to support 100% of the body's weight. This overload works the calves and Achilles with a force equal to 6 times the body's weight upon impact