Posted: June 19, 2005

Science of Sport: All but six of the 500 fastest times for the 100-metre dash have come from sprinters of West African descent

Last summer, Prof. Caulfield was surprised to read an article in the prestigious journal Science titled, “Peering Under the Hood of Africa's Runners.” It noted that all but six of the 500 fastest times for the 100-metre dash have come from sprinters of West African descent, which includes most U.S. blacks. Kenyans, meanwhile, dominate world records in long-distance races.

According to the report, Swedish physiologists trying to penetrate the “Kenyan mystique” compared runners from Africa and Scandinavia on treadmill times, lung capacity, heart rates and body weights. Limb measurements indicated that the Kenyans carried 400 grams less flesh on each calf. The report referred to their “birdlike legs,” explaining how Kenyan runners squeeze more power from their oxygen intake, since “they need less energy to swing their limbs.”

Research on West Africa's sprinters, meanwhile, revealed a body type of heavier “fast-twitch” muscles, versus the lighter “slow-twitch” muscles of endurance runners, as well as denser bones, narrower hips, thicker thighs, longer legs and lighter calves. Efforts are now under way to decode the genetics behind all these traits.

Like Prof. Harpending's paper on Ashkenazi Jews, the report on African runners presented a positive picture of its subjects, albeit a stereotypical one. Yet it seemed eerily reminiscent of ugly 19th-century efforts to gauge racial differences with calipers and cranial measurements.

Prof. Caulfield, who holds the Canada Research Chair in Health Law and Policy, was mostly concerned about where such research would lead. Already, he said, an Australian company is cashing in on the notion that some people are born to run, offering to test a child's genes for fast- or slow-twitch muscles — “so you know which sport to put your kid in.”

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