Trampoline

A trampoline is a piece of taut fabric held inside a steel frame by coiled springs, with the springs rather than the fabric itself providing the bounce by storing and releasing energy. George Nissen and Larry Griswold, both competitive athletes at the University of Iowa, built the first modern trampoline in 1936 by stretching canvas fitted with grommets across an angle iron frame using coiled springs, originally intended for tumbling training. Nissen named the device after the Spanish word trampolin, meaning diving board, after encountering the term on a demonstration tour of Mexico in the late 1930s, and the two men founded the Griswold-Nissen Trampoline and Tumbling Company in Cedar Rapids, Iowa, in 1942 to manufacture it commercially. The device was originally called a rebound tumbler before trampoline became the generic name, and it is now used for recreation, competitive gymnastics, and training for other acrobatic sports such as diving and freestyle skiing. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/