In 1934, an American gymnast named George Nissen, inspired by watching circus acrobats fall onto flexible safety nets and use the rebound to perform acrobatic skills, constructed the first prototype trampoline out of canvas and rubber for inner tubes. Nissen called his device a trampoline after trampolํn, the Spanish word for springboard. Trampolining caught on quickly as a backyard activity and was even used to teach pilots air sense in World War II. As a sport, Trampolining was slower to catch on. The first U.S. National Championships in Trampoline were held in 1948, but a World Championships in Trampoline were not held until 1964. At its first World Championships, held in 1964 at London's Royal Albert Hall, Trampoline was a sport without a governing body. It wasn't until after the competition, won by Americans Dan Millmann and Judy Wills, that the F้d้ration Internationale de Trampoline (FIT) was officially established. By this time, Trampoline was so popular that it had come to the attention of the FIG, which had voted 11-1 to reject Rudolf Spieth's suggestion to include Trampoline as an FIG discipline three years earlier. The FIT flourished over the next 30 years and was recognised as an international federation by the IOC in 1988. The road to becoming an Olympic sport ran for a decade, as Trampoline pursued a strategy of "seduction" that included top trampolinists performing outside the Olympic Museum in Lausanne for an audience that included then-IOC President Juan-Antonio Samaranch and members of the International Olympic Committee. Per joint decision, the FIT was dissolved at the end of 1998 and Trampoline became a FIG discipline on January 1, 1999. It has been part of the Olympic programme since the 2000 Games in Sydney, where George Nissen, the man who started it all, watched proudly from the stands. Rio 2016 marked the fifth Games to feature Trampoline as part of the Olympic programme. Technological advances to the apparatus have made it possible for trampolinists to achieve greater heights than ever before. Time of Flight, the amount of time a gymnast spends in the air, and Horizontal Displacement, the factor that measures the distance "travelled" from the centre of the trampoline, now count as part of a gymnast's score, along with Difficulty and Execution. No country has embraced Trampoline more than China, which produced at least one gold medallist at the World and Olympic level every year from 2007 to 2015. Russia, Canada, and Belarus are also dominated forces in the sport.