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
2012 Olympic Marathon Course along the Victoria Embankment with the regular London Marathon course, the Olympic event also started in The Mall whilst the London Marathon starts in Greenwich, and the event followed an otherwise different course. The logistical problems behind the design of the London Marathon course (35,000 runners of mixed ability) are very different from those behind the design of the London Olympic Marathon course (100 top-class runners) hence the difference in the routes. The course for the Paralympic Marathon also had four laps which were nearly identical to the 2012 Olympic Marathon course, but avoided certain cobbled areas notably Paternoster Square,