Sprinting ahead of his time

Last year, while watching the Beijing Olympics, I was blown away by how much faster Usain Bolt was than everybody else. He became the first man to run the 100-meter dash in under 9.7 seconds. Now, I thought, that's really, really fast. But then, just this month, there was a race between the "World's Fastest Men" in Berlin, and Bolt said he would break his own record. The result? 9.58 seconds. An average speed of 23.4 miles per hour (37.6 kph).

It isn't like humans can't run faster instantaneously, as Donovan Bailey, for an instant, has been clocked at 12.1 meters per second (27.1 mph / 43.6 kph), and it isn't like we can't run faster (like during a relay) if we get a running start. (Carl Lewis' 8.8 second split in the 1992 Olympics is still one of the fastest relay splits ever.) But for the 100-meter dash — where you start from rest — this is unheard of. If we look at the progression of the men's 100-meter world record, we can really get a feel for how special this really is. Let's take a look at how the record has changed over time:

You see, there ought to be some intrinsic limit of how fast humans can possibly run. There ought to be some physical, anatomical limit to how quickly we can — starting from rest — cover 100 meters. Luckily, simply modeling this mathematically — by an exponential — will tell us what the world record progression ought to look like, and should tell us what the theoretical limit of the human body is.

Not only that, but we can predict what the future record ought to be.

What do we find?

Okay, first off, mathematically, it looks like the theoretical limit of how fast humans can run the 100-meter dash is somewhere around 9.2 seconds, but it looks like we won't get there for hundreds of years.

But second off, you can also see that Usain Bolt is running much faster than humans ought to be running right now. This should give you an inkling of just how special these performances we're seeing from him are. We shouldn't be seeing times like this until the 2030s. Which means, honestly, that it ought to take around 30 years for someone else to come along and break his record.

So what do we learn, practically, from doing this math? That watching Usain Bolt run is like watching Bob Beamon's long jump in 1968; it's a record that should stand for at least a generation.

Ethan Siegel is a theoretical astrophysicist who currently teaches at the University of Portland in Portland, Ore. This post originally appeared on his blog, scienceblogs.com/startswith abang, and is reprinted his permission. Siegel points out that he is not a physiologist, and that what he wrote up in his blog is based on a definitively oversimplified model, mostly for fun.