<P> The two main types of freestyle events are: </P> <Ul> <Li> Big Air (also known as Best Trick), in which each rider gets two jumps--usually covering more than 75 ft (22.8 m)--from a dirt - covered ramp . A panel of judges evaluates the style, trick difficulty, and originality and produces a score on a 100 - point scale . Each rider's highest single - jump score is compared; top score wins . </Li> <Li> Freestyle motocross, the older of the two events, in which riders perform two routines, each lasting between 90 seconds and 14 minutes, on a course consisting of multiple jumps of varying lengths and angles that generally occupy one to two acres (. 4 to . 8 hectares). Like Big Air, a panel of judges assigns each contestant a score based on a 100 - point scale, looking for difficult tricks and variations over jumps . </Li> </Ul> <Li> Big Air (also known as Best Trick), in which each rider gets two jumps--usually covering more than 75 ft (22.8 m)--from a dirt - covered ramp . A panel of judges evaluates the style, trick difficulty, and originality and produces a score on a 100 - point scale . Each rider's highest single - jump score is compared; top score wins . </Li> <Li> Freestyle motocross, the older of the two events, in which riders perform two routines, each lasting between 90 seconds and 14 minutes, on a course consisting of multiple jumps of varying lengths and angles that generally occupy one to two acres (. 4 to . 8 hectares). Like Big Air, a panel of judges assigns each contestant a score based on a 100 - point scale, looking for difficult tricks and variations over jumps . </Li>

Who did the first backflip on a dirtbike