Usain Bolt, the 21-year-old Jamaican who set a world record in winning the Olympic 100-meter dash this weekend, is the most extraordinary sprinter in track-and-field history. Not because he's so fast, but because he's so big. At six-foot-five, Bolt has been called by Sports Illustrated"the tallest world-class sprinter in history." He's easy to spot on the track, Goliath-ing over his human-scale opponents. The starting blocks cramp his frame. As he kneels for the gun, his rump rises high above his competitors'. Once the race starts, he looks like a high schooler who lied about his age to win a Field Day ribbon. Bolt takes 40 to 41 strides in a 100-meter race. Walter Dix, the 5-foot-9 bronze medalist, takes 47.
If Bolt's long legs give him such an edge, why haven't there been more tall sprinters? Traditionally, height has been seen as a detriment to sprinting. The formula for speed is stride length times stride rate. If the longest legs always won the race, then Yao Ming would have the world record in the 100, and lions wouldn't eat giraffes. Gangly guys, the thinking has always gone, don't win short races because they can't master the smooth form required to generate rapid leg turnover. Sprinters are supposed to be compact and muscular: Think Ben Johnson or Ato Boldon.
Big guys have physics working against them. According to the Journal of Sports Science & Medicine, "[T]he acceleration of the body is proportional to the force produced but inversely proportional to the body mass, according to Newton's second law. … This implies an inverse relationship between height and performance in disciplines such as sprint running." In other words, it's hard to produce enough power to overcome the drag of a big body. Usain Bolt, science tells us, is a top-heavy minivan racing against a field full of Suzuki Hayabusas.
That Journal of Sports Science & Medicine study, which may now need to be rewritten, found that world champion sprinters ranged between 5-foot-9 at the low end to 6-foot-3 at the absolute max. (Unlike distance runners, sprinters do need to be big and strong enough to generate explosive speed. That's why 5-foot-9 has traditionally been the minimum height, whereas the elite distance runner Haile Gebrselassie is a mere 5-foot-3.) That range covers all the recent gold medalists, from Maurice Greene to Linford Christie. But not Usain Bolt.
Yet on Saturday night, the tall guy ran away from his classically designed competitors, winning by such a wide margin that he had time to wing out his arms, pound his heart … and still set a world record. If he stays healthy, Bolt could not only lower the mark to a science-fiction-y 9.6 seconds; he could change the look of future sprinters. He is a hybrid never before seen in track and field: a spidery giant whose legs generate the propulsive power of a cannonball-thighed running back.
When Bolt first took up track, he suffered from tall man's maladies. For one thing, he ran as if he were wearing seven-league boots. His coach, Glen Mills, sped him up by shortening his stride. "Biomechanically, his body placement was not ideal for sprinting," Mills told the Jamaica Gleaner. "His head was back, his shoulders were well behind his center of gravity, this resulted in him spending too much time in the air and over-striding." Now, Mills says, "his length of stride is compatible with his height. One of the reasons he has such a long but efficient stride is because he lifts his knees so well."
Good news for tall sprinters of the future: Bolt and Mills have developed the ideal gait for a 6-foot-5 runner. It allows Bolt to use his size as a motor rather than a brake. Still, he doesn't have a classic sprinter's carriage. In the 100, he sometimes looks rickety, wobbling back and forth on the track; a less-coordinated athlete with the same dimensions might topple over as he bounds down the straightaway. Sometimes, he still lifts himself too high in the air, especially on the turn in the 200 meters. (It's hard to see how that flaw will keep him from winning a second gold medal, though.)
So will the starting blocks at the 2012 Olympics be filled by giants? Probably not. One reason we've never seen such a tall sprinter is that athletes who combine height and coordination usually go out for more glamorous, high-paying sports. Usain Bolt would make a sensational wide receiver or a great rebounding forward. In the United States, at least, a lot of guys started running track because they got cut from teams with cheerleaders. But Jamaicans regard sprinters the way the French regard wine: as a leading export, and a source of national identity. Asafa Powell, who held the world record before Bolt (and who finished fifth in Beijing, continuing a string of big-race washouts), owns six cars and has been awarded the country's Order of Distinction. America's Tyson Gay, by contrast, is less well-known than pretty much every NBA benchwarmer.
While Bolt's amazing feat likely won't inspire the next generation of Kobe Bryants to exchange their hightops for track spikes, he will undoubtedly be an inspiration to his fellow countrymen. Bolt has confessed that his first love was cricket, but his victory in the 100 made him a hero in a way the bat and ball never could have. He could be a one-off athletic freak, defying Newtonian physics, or the prototype for a new breed of bigger, faster sprinters. I'm guessing we'll find out in years to come, as long-legged Jamaicans drop their cricket bats and head for the track.