The modern track omnium is held on an oval-shaped indoor cycling track, or velodrome. This track is steeply banked.
The omnium, as regulated by the Union Cycliste Internationale (UCI), consists of five events: a 200m flying start time trial; a 5 km scratch race; a 3 km individual pursuit; a 15 km points race; and a 1 km time trial.
Track omniums are held as one-day events with riders allowed up to 30 minutes to rest between individual events.
Although track bikes look similar to road bikes, the major difference is that track bikes have no brakes. They utilize a single fixed rear gear, unlike the multiple gears in a road bike. This set-up allows for maximum speed, eliminates sudden braking while in close proximity to other riders and reduces the bicycle's weight.
Cyclists riding in a track omnium must have a mix of endurance, power and speed to successfully compete in an omnium's wide range of distances.
Road omniums typically consist of three races, held over 2 to 3 days, with riders competing for cumulative points. Each of the three races typically include a 10 to 20-mile time trial; a criterium (riding a specified number of laps, or time, on a looping course); and a 25 to 60-mile road race.
Due to the nature of the road omnium and the courses, cyclists use road racing bikes outfitted with brakes and multiple gears to better handle the varied terrain that will be encountered in the outdoors.
Due to the distances involved in a road omnium, and the nature of the events, cyclists considering competing in a road omnium should be in excellent shape to race in three different, but grueling events over the course of 2 to 3 days.