 The first use of acrobatics as a specific sport was in the Soviet Union in the 1930s, and the first world championships were in 1974.In addition to the current five categories, two additional categories for tumbling (men's and women's) were included until the 1999 World Championships, though some groups still involve tumbling events.In the United States, the first national sports acrobatics organization was called the United States Sports Acrobatics Federation (USSAF).