Those wacky engineers at Carnegie Mellon have created a new, improved pogo stick, the BowGo:
The BOWGO (patented) is a new kind of pogo stick that bounces higher, farther and more efficiently than conventional devices. The BOWGO is a product of the Toy Robots Initiative and is a scaled-up, human-sized version of the Bow Leg. The Bow Leg is a highly resilient leg being developed for running robots at Carnegie Mellon University’s Robotics Institute. The key technology is the fiber-reinforced composite (FRC) spring that bends like a bow to store elastic energy. Compared to the steel coil spring used in a conventional pogo stick, the bow spring stores 2-5 times as much energy per unit mass, and precludes the sliding friction that results when long coil springs buckle sideways. The BOWGO also uses rollers to guide the plunger, in place of the usual plastic guide bushings, providing smooth, almost frictionless motion. The force/deflection characteristic of the bow spring is tailored to provide high-energy storage with minimal shock at ground contact. A large, rubber-padded foot allows the BOWGO to be used on relatively soft surfaces such as grass, sand and gravel.