Long-distance running only the placing is of importance. Other less popular variants such as fell running, trail running, mountain running and tower running combine the challenge of distance with a significant incline or change of elevation as part of the course. Multisport races frequently include endurance running. Triathlon, as defined by the International Triathlon Union, may feature running sections ranging from five kilometres (3.1 mi) to the marathon distance (42.195 kilometres, or 26 miles and 385 yards), depending on the race type. The related sport of duathlon is a combination of cycling and distance running. Previous versions of the modern pentathlon incorporated
Athletics at the 1908 Summer Olympics – Men's marathon yards on the track") eventually became the origin of the modern Marathon distance of "no less than 42.195 km". According to the book "The Marathon Makers" by John Bryant, the first mile of the 1908 Olympic Marathon course was remeasured by John Disley in the late 1990s and was found to be 174 yards (159 m) short. The official report lists the leaders at each mile from the fourth to the twenty-fourth: Thomas Jack (miles 4–5); Frederick Lord (miles 6–14); Charles Hefferon (miles 15–24). Dorando Pietri of Italy caught Hefferon and sped up between Old Oak Common Lane and Wormwood