Note: Single-source report; awaiting corroboration.
Ultramarathon races are typically categorized into two main types: those decided by specific distances, such as 50km and 100km races, and those determined by a fixed time period, including 6-hour, 24-hour, and multi-day events. These competitions can be held on trails, tracks, roads, or a combination, each presenting unique challenges for athletes.
The International Association of Ultrarunners (IAU), established in 1984, serves as the global governing body for ultramarathon running. Affiliated with World Athletics, the IAU promotes, develops, and regulates ultrarunning internationally. It organizes major competitions such as the 50km, 100km, and 24-hour World Championships, as well as continental championships for the Americas, Asia and Oceania, Europe, and Africa, typically held on a biennial basis.
In addition to overseeing competitions, the IAU honors significant contributions to ultrarunning, including career awards and the Athlete of the Year distinction. The association also maintains official records for various ultramarathon distances. Malcolm Campbell of Great Britain, the first IAU President, is an honorary member recognized for advancing the sport globally.