What is "jumpsoles"

Jumpsoles are weighted platforms that attach to your shoes. Although invented primarily for basketball players, the platforms are now used by athletes in other sports. Users stand with their heel off the ground and practice jumping for a short time, often no more than 20 minutes. The exercises, according to Black Belt Magazine, are supposed to "build fast-twitch muscle fibers, which are integral to developing explosive power and quickness". They can improve the user's vertical leap by to and build calf and thigh muscles.