The Speed Limit of The Fastest Man Alive

By Norman Chan

Mathematicians say that Usain Bolt is poised to break his 100-meter world record this year. But how fast can he go?

The Summer Olympics are coming up, and many eyes in London will be locked on Usain Bolt, the current world record holder for the 100-meter sprint. Bolt, who astounded the world in 2008 with a Gold Medal performance that looked effortless (and some would argue, unsportsmanlike), is poised to break his own amazing records. In fact, he had already broken the 9.69 second record he set in 2008 with a 9.58 second run at the World Championships in Berlin. But just how much more time can the hero of Jamaica shave off his run time? Mathematicians around the world who have studied Bolt's physique and technique have differing opinions. Stanford University's Mark Denny, using examples and historical data from other athletic competitions, estimated that Bolt would plateau at 9.48 seconds. John Barrow, a mathematician at Cambridge, has a more aggressive estimate of 9.45 seconds.

Borrow notes that Bolt can make significant improvements to his time off the blocks--the reaction time after hearing the starter pistol go off. In Berlin, Bolt was actually the slowest of the competitors to react, but still handily won the race. The other variable that could help Bolt, according to Barrow, would be faster tailwind. If Bolt was assisted by the maximum tailwind allowed of 2 meters per second, he would be running against less wind resistance and could achieve a faster top speed. Start reaction time is something Bolt can refine with practice, while tailwind would be out of his control. But the combination of those ideal conditions is how Barrow sees Bolt beating his current record by .13 seconds--an incredible difference for someone who's already the fastest man on the planet.

Photo Credit: Flickr user oneris via Creative Commons

While Bolt setting history once again isn't certain, scientists agree that Bolt is nothing short of a phenomenon in human running ability. A great Esquire profile on Bolt in 2010 basically called Bolt a mutant--a man far ahead of his time in terms of what should be possible. From the profile:

Ethan Siegel, a theoretical astrophysicist at Lewis & Clark College, recently charted a graph to demonstrate that, judging by the incremental progression of the 100-meter world record over the past hundred years, Bolt appears to be operating at a level approximately thirty years beyond that of the expected capabilities of modern man. Mathematically, Bolt belonged not in the 2008 Olympics but the 2040 Olympics. Michael Johnson, the hero of the 1996 Olympic summer games, has made the same point in a different way: A runner capable of beating Bolt, he says, "hasn't been born yet."

But even if he performs at his most optimal, most researchers believe that Bolts records will eventually be broken. It's only a matter of time. The theoretical speed limit of a human being, according to a 2010 study conducted at Southern Methodist University, may be up to 40 mph, based on what scientists think is the maximum amount of force a runner's legs can apply to the ground. Bolt currently averages 28 miles per hour.