In honor of week two of the olympics

I found this article really insightful...

Jamaicans dominated the Olympic 100-meter sprint this weekend, with Usain Bolt setting a world record and his teammates taking all three medals in the women's event. Jamaica is a poor, tiny nation about half the size of New Jersey. What makes its people such champion sprinters?

A combination of nature and nurture. Runners of West African descent—which includes Jamaicans as well as most African-Americans—seem to be built for speed: In 2004, they held all but five of the 500 best times in the 100-meter dash. (East Africans, such as Kenyans and Ethiopians, rule the long-distance field.) Several biological factors may be coming into play here. One study conducted in Quebec in the 1980s found that black West African students had significantly higher amounts of "fast-twitch" muscle fibers—the kind that are responsible for short, explosive bursts of action—than white French Canadians did. (So far, there is no evidence that even extensive training can turn slow-twitch muscles into fast-twitch ones, though moving in the other direction is possible.)

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