Jamaicans Spell Speed 'D-N-A'

Jamaicans sprinters are cleaning up in Beijing, thanks to both biology and their backgrounds. Runners of West African descent—including Jamaicans—have more "fast-twitch" muscle fibers, the kind that generate quick bursts of energy, Slate explains. But nature alone didn't propel 100-meter champ Usain Bolt to his record-breaking, chest-thumping gold.

There are cultural factors at play, too. The national high school track and field championships, "the importance of which to Jamaicans rivals that of the Super Bowl to Americans," Nina Shen Rastogi writes, "plus the 45 Olympic medals Jamaicans have now won in track—helps inculcate a deep sense of national pride in the sport."