Downhill cycling (DH) is a gravity-assisted time trial mountain biking event. Riders race against the clock, starting alone at set intervals, on courses which typically take two to five minutes to complete. The fastest rider to complete the course places first. As the name of this discipline implies, downhill races are held on steep, downhill terrain with no extended climbing sections, resulting in much higher speeds than in cross-country racing. The terrain is also often somewhat rougher than in cross-country racing. The bike is specialized and has a long travel suspension and powerful disc brakes.
While the riders job is to get top to bottom as fast as possible, the course designers have their work cut out challenging the rider and making the job of going fast more difficult. Downhill courses usually feature big jumps and drops, as well as often being either covered with roots or rocky (occasionally both). A common feature is a “rock garden”, which is a strip of moderately sized rocks.