UltraRunning Sources, References & Definitions :
1. Wikipedia : Ultra Running / Ultramarathon / Ultramarathons categories. "An ultramarathon (also called ultra distance) is any sporting event involving running longer than the traditional marathon length of 42.195 kilometres (26.2188 mi)." Well known, popular & famous ultramarathons : Well-known ultramarathons sub-category. A growing trend is barefoot ultra running : "running ultramarathons while barefoot - without wearing any shoes on the feet."
2. Wikipedia : Multiday race category. "Multiday races are ultramarathon running events which are typically either segmented into daily events of a specified distance or time, or staged so that runners can run as far as they want, at their own discretion, over a set course or over a set number of days. Multiday races can range from continuous 48 hour track events to staged transcontinental treks."
"Very long endurance running events can be divided into three broad categories: the traditional 26.2-mile (42.2 km) marathon, the ultramarathon, defined as any event longer than the marathon, and true multiday events, which begin with the 48 hour event and can stretch out almost indefinitely, often ranging from six days to 3,000 miles (4,800 km) or longer." Well known, popular & famous multi-day (multistage) races : Well-known multiday races sub-category.
3. Facebook : Ultrarunning. Wiki "Facebook Community Page about Ultrarunning, a collection of shared knowledge..."
4. dmoz Open Directory Project (ODP) : Ultramarathon category; Ultramarathon Events category. "An ultramarathon is a footrace longer than a marathon (26.2 miles)."
5. Alexa - Top Sites by Category : Ultramarathon
6. iaaf.org : Ultrarunning. "Ultrarunning is a unique sport that gives the athlete the loneliness of a runner but also provides the camaraderie and companionship that is not seen in many disciplines of other sports. On paper, an ultra race would be as small as a meter more than a marathon distance. However, stemming away from the truly literary definition, 50 km and 100 km races are the most common around the world."
7. IAU : International Association of Ultra Runners. "The governing body for the sport of ultra running around the world" according to the iaaf ( International Association of Athletics Federations ). Accoding to the IAU, "Today there are more than a thousand ultra races around the world with more than a hundred thousand ultra runners. It is no more an unrealistic event. The IAAF granted its patronage to the IAU in 1988 and the 100km race became a standard distance recognized by the Federation." Today the IAU organise four world and European ultramarathon championship events. Ultramarathon records : IAU World Best Performances.
8. Yiannis Kouros : What is Ultra Running. "Ultra-running, in its precise description, is a competitive, but continuous (when the race clock does not stop during the same and entire race) running sport, organized officially under internationally set regulations where judges control the entire event and its scoring development, and takes place on the track (indoors or outdoors) or on the road -touching the ground and not an apparatus, like a treadmill, moving mechanically or electronically or by any other artificial means- for a period of time beyond 24 hours..."
9. Association of Road Racing Statisticians ( ARRS ) : Longest Running Ultramarathons. "... an attempt to list all ultramarathons world-wide that have been held 20 or more times ( runnings )." "Complete winners / dates / times list for 61 ultramarathons. Complete winners list for 100 ultramarathons."
10. World Megamarathon Ranking 300+. "World Megamarathon Ranking list for marathon and ultra runners with 300 or more marathon and ultra finishes."
THE UltraRunning Resources of the World :
DUV Ultra Marathon Statistics
Results & Rankings Database : statistik.d-u-v.org.
Ultramarathon results database containing at the moment 1151618+ performances of 337066+ runners achieved in 13820+ ultramarathon events. Ultra runner rankings are generated of this database if the event was record eligible. Also available is an ultra runner results search function, providing a list of ultra runs with times/results, dates, overall position, personal bests and a comparison table. National and international ultramarathon records/best performances included.
Bryon Powell's iRunFar : iRunFar.com.
"A trail running and ultramarathon resource ( blog ) featuring trail running and ultrarunning news, gear reviews, training and racing advice." Particular focus on the performances of elite/best ultra runners at major US ultramarathon events, including interviews with Anton Krupicka, Geoff Roes, Hal Koerner, Krissy Moehl, Liza Howard, Scott Jurek as well as Ian Sharman, Jez Bragg and other top ultramarathon runners. List of ultramarathon coaches for the US.
Abichal Watkins' Multidays : Multidays.com.
"News and results of multiday races, ultramarathons and ultrarunning events and calendars around the world." Specialist multiday running site with multiday race results, news, race reports, links, interviews, long distance running world record attempts/performances, charity runs & solo attempts, extreme ultra running articles & extensive calendars by category, including 24 hours, 48 hours, 6 day, 10 day and Sri Chinmoy ultras.
Stan Jensen's Ultramarathon Guide : Run100s ( "Run Hundreds" ).
"The definitive starting place for ultras (ultramarathons), with information and statistics for the top races in the USA." Extensive details of all North American 100 milers with dates, entry fee, runner limit, location, cutoff, course record, aid stations, elevations, results, history, photos, reports and other statistics. Including Angeles Crest 100, Hardrock 100, Leadville 100, Wasatch 100, Old Dominion and Western States 100 mile ultramarathons. Also includes ultramarathon coaching, blog and club links as well as ultra slams and series including 'The Grand Slam of Ultrarunning'.
UltraRunning Magazine Online : UltraRunning Magazine.
"UltraRunning is published 10 times a year, monthly except for combined January/February and May/June issues." Particular focus on ultra trail races. Features include North American race results, race reports and news, ultra calendar, pace calculator, featured races and interviews with ultrarunners. With an extensive database of "Training and Racing / Medical and Nutrition" articles, including research and medical issues, all written by experienced ultramarathoners.
URC | Facebook
Ultra Running Community Facebook Group : Ultra Running Community
"a large ultra running Facebook group that means responses are fast and numerous. A place to visit for ultra running questions, advice and plenty of banter. Many members are from the UK but there is an international flavour. Everyone is welcome.
Kevin Sayers' Ultra Running Resource Site : UltRunR.
"A site dedicated to numerous informative topics on the subject of Ultra Running also referred to as the Ultra Marathon." Extensive collection of ultrarunner's experiences on a wide range of ultra trail running topics, including cross training, recovery, sodium/salt/electrolytes, stomach problems, heat acclimation, altitude, supplements, injury prevention and care, blisters and foot care, chafing, medical studies, hill training, race strategy and aid station strategies, crews, ultramarathoning gear/clothing and coaching.