The Tarahumara Indians of southwestern Chihuahua are the ones who can run 100 miles at a clip without it seeming to be a big deal. Then do it again the next day.
Some enterprising person brought them to the Olympics (Amsterdam, 1928) to compete in the Marathon and they didn’t even place.
The problem was no one had explained to them that the race was only 26 miles long. They thought they were just warming up.