Trampolines

A trampoline is a device consisting of a piece of taut, strong fabric stretched between a steel frame often using many coiled springs. People bounce on trampolines for recreational and competitive purposes, and it can be used for gymnastics. The fabric that users bounce on (commonly known as the "bounce mat" or "trampoline bed") is not elastic itself; the elasticity is provided by the springs that connect it to the frame, which store potential energy.