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
Long-distance swimming Some of the better-known long-distance swims are crossings of the English Channel, Catalina Channel, Fehmarn Belt and Cook Strait. Ultra-long distance swimming is sometimes referred to as marathon swimming. The minimum distance that constitutes a marathon swim has dramatically shortened over time. Different organizations adopt various minimum distances. The swimming marathon events at the Olympic games have a distance of 10 km. Long-distance swims tend to fall into one of two categories: (1) swims in which the start date and start time are chosen by the individual swimmer (often called solo-swims), and (2) swims that involve a group-start. Long-distance swimming