The trampoline or gym is an entertainment tool used to practice sport and exercise.  The modern trampoline was first established at the University of Iowa in the United States in 1934 by American gymnasts George Nissen and Larry Griswold, as it was initially used to train acrobats who practice flying The showman, and astronauts, in addition to using it as a training tool to enhance acrobatic skills in other sports, such as: diving, gymnastics, and freestyle skating, and it is worth noting that the first appearance of trampoline in the Olympic Games was in 2000 in Sydney, Australia. 
Types of trampolines
There are two types of trampolines, the first is the regular trampolines, and the second is the mini trampolines . The regular trampoline, which rises from the ground from about 90 to 120 cm, is designed for practicing sports, and the mini trampoline is intended for practicing specific exercises without Others, such as rebound exercise, and from 30 to 60 cm off the ground. 
There are many benefits to trampoline, including the following: 
- Reducing joint pain and the common wound injuries that a person may be exposed to while practicing other sports; Jumping on a trampoline leads to an even distribution of pressure on the ankles, back and forehead area when bouncing, but when running, for example; Most of the pressure is on the ankles. This causes repeated injuries, according to the results of NASA studies.
- Cell strengthening and cardiovascular health; Jumping in the air leads to the arrival of a greater amount of oxygen to the cells of the body upon rebound, then leads to strengthening them and enabling them to endure more exercises efficiently.
- Enhancing physical strength and muscle growth ; Cornell Hospital conducted a study of five healthy people. Where they were subjected to measuring the extent of their stress by standing on one leg with the eyes closed, before and after two months of training on the trampoline three times a week and for twenty minutes each time, as the results showed that the time that a person can stand on one leg has increased to several Seconds after training, which is important to reduce sports injuries.
- the Van Thompson (11-9-2017), "The Difference of a Rebounder & the Between Trampoline" , Www.livestrong.com , Retrieved 8-3-2018. Edited.
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