Running is not an extreme....hundreds of thousands of people are avid runners and do half/full marathons every year. Running is an extreme to someone who bbs and can't run the length of a city block without oxygen and difibrilator.
No, of course running is not extreme, it is natural. What IS extreme is running in marathons. That's why the human body looks the way it does. That's why women look the way they do, those who run marathons. There is no reason to run that far, just as there is no reason to look like a bodybuilder. They serve no NATURAL purpose. The man and female bodies start ro resemble each other. The women have low estrogen levels and the men have the lowest test levels of any athlete. That is nothing to brag about.
In the animal world, the fastest land mammal is the cheetah, but it made the trade off for having maximum speed, no endurance and no size, strength or muscle mass. The middle ground in terms of big cats, is the leopard--size, strength, agility and speed.
Now onto humans, humans have adapted to many diff environs, those among the east Africans have light builds and run a lot, good for long distances.
