A trampoline is a device consisting of a piece of taut, strong fabric stretched between a steel frame using many coiled springs. People bounce on trampolines for recreational and competitive purposes. 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.
There are two generic types of trampoline, competitive and recreational.
The frame of a competitive trampoline is made of steel and can be made to fold up for transportation to competition venues. The trampoline bed is rectangular 4.28 by 2.14 metres (14 ft 1 in × 7 ft 0 in) in size fitted into the 5.05 by 2.91 metres (17 ft × 10 ft) frame  with around 110 steel springs (the actual number may vary by manufacturer). The bed is made of a strong fabric, although this is not itself elastic; the elasticity is provided only by the springs. The fabric can be woven from webbing, which is the most commonly used material
Recreational trampolines for home use are less sturdily constructed than competitive ones and their springs are weaker. They may be of various shapes, though most are circular, octagonal or rectangular. The fabric is usually a waterproof canvas or woven polypropylene material. As with competitive trampolines, recreational trampolines are usually made using coiled steel springs to provide the rebounding force, but spring-free trampolines also exist.