A height-adjustable apparatus using a spring to urge forward and rearward undulating whippy locomotion is disclosed. A hand-crawling embodiment having a hand-glove assembly affixed to a base assembly enables users to engage in all-fours crawling locomotion while the body is conventionally situated in a two-legged orientation. One embodiment includes a forearm support bracket mounted at either a permanent or adjustable wrist angle. An internal stabilizer cylinder retainer is also provided to reduce inward pivoting of the internal stabilizer cylinder retainer in the direction of the opposite hand while permitting outward pivoting toward the outside of the device, and front-to-back pivoting toward the front side or backside of the device. A similar foot-bounding embodiment enables walkers, joggers, runners and jumpers to engage in forward and backward whippy locomotion. A crutch embodiment having a similar base assembly enables crippled or injured users to likewise engage in whippy locomotion.
