GOING FOR THE GOLD: Michael Phelps, a swimmer from Baltimore has now won more gold medals than anybody else in Olympic history. How does he do it?
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Now that Michael Phelps has won an unmatched eight gold medals in this year's Olympic Games, lots of journalists are asking what gives Phelps such a leg up on the competition (legally, of course, though allegations of doping have tainted other Beijing Olympians). Beyond Phelps’ drive to succeed, as reported by the Australian Broadcasting Company, and his undoubtedly good training, could it be that a good bit of his (as well as many athletes’) talent just boils down to simple anatomy?

There's his proportionally longer “wingspan,” as described by the Toronto Sun newspaper. Phelps’s arms extend 80 inches (203 centimeters) tip to tip, and his body measures in at 76 inches (193 centimeters) in height. Most of the time, a person’s height normally corresponds closely to the distance between his outstretched hands. (Recall Leonardo da Vinci’s Vitruvian Man, that famous sketch of a naked male showing his arm-leg-torso ratios.) Maybe this extra reach gave Phelps that narrowest of victories against Serbia’s Milo Cavic in the 100-meter butterfly final on Saturday, August 16, when the American won by just one one-hundredth of a second.

Phelps is also said to be double-jointed, according to a Detroit News blog. His size-14 feet reportedly bend 15 degrees farther at the ankle than most other swimmers, turning his feet into virtual flippers. This flexibility also extends to his knees and elbows, possibly allowing him to get more out of each stroke.

Do any of these alleged anatomical advantages matter? To find out, ScientificAmerican.com spoke to H. Richard Weiner, an internist and former team physician who has practiced sports medicine at the University of Wisconsin--Milwaukee —and who also happens to be a former acclaimed All-American swimmer.

An edited transcript of the interview follows.

What do you think about the notions about Phelps’s built-in, anatomical advantages?

When someone does something statistically impressive, like winning eight gold medals like Phelps, we try to come up with some far-fetched reason for it, like he or she has to have some bizarre physiological adaptation or freaky anatomy. But most things that you measure in human beings fall within predictable ranges.

What do you think about the "wingspan" argument—that Phelps’s long arms give him an edge?

All things being equal, a taller person [with longer arms than a shorter person] will swim faster. A lot of the thrust in swimming comes from arm propulsion and not the kick. But then again, the person who won [the men’s 100- and 200-meter] breaststroke is a five-foot, eight- [1.78-meter-] tall Japanese man [named Kosuke Kitajima]. Matt Grevers, a U.S. swimmer from Northwestern University [in Illinois], is six foot, eight [2.03 meters]. I stood next to him and his arms are, heaven knows, more proportional to a guy who is seven feet [2.13 meters] tall. When he does [the] backstroke and you’re standing on deck, it looks like a tree is coming out of the water. And [Grevers] has done well, but not as well as Phelps. So height in and of itself does not intrinsically confer success.