A single gene may help explain why some runners are great sprinters while others excel at long distances, according to new research.
Angiotensin converting enzyme (ACE), which regulates blood pressure and metabolic functions, is encoded by a gene with two forms: D and I. To examine the variants' effects on athletic performance, geneticist Hugh Montgomery and colleagues at University College London studied a group of 78 British Army recruits who had gone through the same basic training program. Recruits with two I alleles showed an 11-fold greater improvement with training on a barbell-curling task than those with two D versions of the gene, the researchers reported on 30 November at the London "Genes in Sport" conference.
A gene may favor short-term bursts of muscle power.
Indeed, when the team surveyed elite British athletes, they found that the D allele is more common among top swimmers and 200-meter runners than in the general population. They speculate that it encourages growth of "fast twitch" anaerobic muscle fibers, which generate brief bursts of high- octane power. The I allele, in contrast, was more common in 5000-meter runners and previously has been shown to be more widespread in high- altitude mountaineers. It may encourage "slow twitch" fibers ideal for long stretches of efficient motion, they theorize.
How the ACE gene might influence muscle fiber growth remains unclear, however. And Alex MacGregor, an epidemiologist at St. Thomas' Hospital in London, cautions that muscle performance is just one of many keys to athletic success. "It's difficult moving from a muscle type to getting a person up a mountain," he says.
