An ultramarathon, also called ultra distance or ultra running, is any footrace longer than the traditional marathon length of 42.195 kilometres (26 mi 385 yd). Various distances are raced competitively, from the shortest common ultramarathon of 31 miles (50 km) to over 200 miles (320 km). 50k and 100k are both World Athletics record distances, but some 100 miles (160 km) races are among the oldest and most prestigious events, especially in North America.
Around 100 miles (160 km) is typically the longest course distance raced in under 24 hours, but there are also longer multi-day races of 200 miles (320 km) or more, sometimes raced in stages with breaks for sleep. While some ultras are road races, most take place on trails, leading to a large overlap with the sports of trail running and mountain running.
There are two main types of ultramarathon events: those that cover a specified distance or route, and those that last for a predetermined period (with the winner covering the most distance in that time). The most common distances are 50 kilometres (31.07 mi), 100 kilometres (62.14 mi), 50 miles (80.47 km), and 100 miles (160.93 km), although many races have other distances. The 100-kilometer race is recognized as an official world record event by the International Association of Athletics Federations (IAAF), the world governing body of track and field.[1]
Other ultramarathon races include double marathons, 24-hour races, and multiday races of 1,000 miles (1,600 km) or longer. The format of these events and the courses vary, ranging from single loops (some as short as a 400-metre (1,300 ft) track),[2] to point-to-point road or trail races, to cross-country rogaines.
