on the competitor's choice of routes, the fluidity of riding and tricks performed (style), and sometimes also the time in which the course is completed. Dual Slalom/Dual – Dual Slalom (DS) is a ski-inspired event which pits two riders against each other on two identical man-made tracks side by side with the same jumps and berms, with a rider on each track, and the first across the line wins. The contest has a knock-out format. Dual (DL) events are similar, only two riders share the same course/track. So dual is a contact sport. Four cross – (4X, also known as 'mountain cross' or 'bikercross') inspired by the dual format and by BMX racing, this event pits four riders on the same course from starting gates to finish. There can only be one winner per event, so the races can quickly eliminate riders making the progression faster for a day's events. This is the reason it was chosen as the race-format to replace Dual-Slalom by the UCI at World Cup events. 4X also replaced Dual in the UCI World Cup series in 2002. There is a difference between 4X and mountain cross. In 4X, riders are each given a run down the course which is timed and the top 50% of the field then progress to the elimination rounds. In mountain cross, riders are given three heats against three other riders, and points are allocated for your position in each heat. Again, the top 50% progress to the elimination rounds. 4X is the format raced in world cup however mountain cross is the preferred format for amateur races. Eliminator – Cross-country eliminator (XCE) Marathon – Marathon (XCM) is perhaps the toughest form of mountain biking because riders often have to cover more than 80 km in one race on mountainous terrain. The distances usually vary from 60 km to 100 km. Races often exceed 100 km, but are then termed Ultra-Marathons. Recently UCI has inaugurated the Marathon World Cup. Basically it equals point-to-point (PP) discipline and that means that riders have a mass start from point "A" and they finish at point "B". Enduro – Enduro in its most basic definition is a type of mountain bike racing where the downhills are timed, and the uphills are not. Riders are timed in stages that are primarily downhill, with neutral "transfer" stages in between. The transfer stages usually must be completed within