Jumping Stilts are known by many names including: Powerizers, Powerisers, Powerskips, Velocity Stilts, Flyjumpers, 7 League Boots, SkyRunner, Pro-Jumps, and Powerbocks. Poweriser is the latest in extreme sports! It enables the users to run and jump with super human speed and strength! How's that possible? Powerisers possess a unique fiberglass spring which is loaded with your gravitational potential and kinetic energy! Simply push upon the spring using your weight and the spring pushes back! Poweriser running and jumping stilts will enable you to jump to heights of 5-7 feet and run at speeds of 17-21 mph! A perfect leg training activity!