Athletes can compete on a straight tumbling surface, a trampoline, and/or a double-mini trampoline (a small trampoline connected to a flat trampoline about two feet high). Each discipline is scored separately (an athlete can compete in one, two, or all three disciplines). Power tumbling is broken down into nine levels which range from the very basic forward rolls to the most advanced tumbling skills, such as double backs and multiple twists. The developmental levels of competition are separated by sex, age, and skill level. Elite competition is separated by sex only. U.S.T.A. competitors range in age from 2 years and up.