Humans evolved to be long-distance endurance runners. An interesting New York Times article mentions the ability for humans to run long distances is an evolved trait. Apparently, having good stamina that allowed early human hunters to track their prey for long periods, spanning time and distance, was of great survival advantage.
Tracking prey for long periods over vast distances is necessary to tire out prey animals. This trait can be observed in wolves, animals also known for their ability to track their prey for long periods. Wolves are capable of covering several miles trotting at about a pace of 10 kmph (6.21 mph) and can reach speeds approaching 65 km/h (40.39 mph) during a chase.
Therefore from an evolutionary perspective it makes sense that humans generally are good distance runners. Humans have evolved to run over long distances, with world-class distance runners being at the extreme end of the scale. As mentioned previously, I admire world-class distance runners, who can run on average at sustained speeds* of:
22.82 kmph (14.18 mph) for a distance of 10,000 metres run in 26:17.53 (current record holder is Kenenisa Bekele of Ethiopia); and
20.42 kmph (12.69 mph) for a marathon (42.195 km) run in 2h03:59 (current record holder is Haile Gebrselassie of Ethiopia).
However, I don’t especially admire their physique (particularly female marathon runners):
In comparison, the world’s fastest man in terms of sprinting short distances is Jamaica’s Usain Bolt who sprints at 37.58 kmph (23.35 mph) over a distance of 100 metres. So a world-class marathon runner is able to run at a little over half of Bolt’s top speed over 100 metres … but can do so 422 times consecutively. This is simply astonishing.
* These times are based on men’s events
“Lightning” Bolt vs Duracell “Battery” Bekele