Physicists estimate how fast Usain Bolt could have run

September 11, 2008 By Lisa Zyga feature
This photo montage shows Usain Bolt’s position relative to the other runners, both in the real race (left Bolt) and Bolt’s projected position (right Bolt, crossing the finish line). Credit: H. K. Eriksen, et al.

(PhysOrg.com) -- By the record books, Jamaican runner Usain Bolt is the fastest human being on earth, and yet no one knows for sure exactly how fast he really is. At the Beijing 2008 Olympics, on Saturday, August 16th, Bolt broke his own world record (9.72 seconds) with a time of 9.69 seconds in the 100-meter dash. But with 20 meters remaining, the 21-year-old looked around, and, when realizing he had a strong lead, he started celebrating before he crossed the finish line.

After watching this jaw-dropping behavior, many people have wondered what Bolt’s time would have been – i.e., what the fastest time ever run by a human could have been – if he had raced the entire way.

Among the curious fans is a team of physicists from the University of Oslo led by Hans Kristian Eriksen, who has recently predicted Bolt’s hypothetical world record based on factors such as his acceleration and velocity. By extrapolating from Bolt’s speed before celebrating, the physicists estimated that the new world record would have been about 9.55 ± 0.04 seconds.

Their estimate would support the claim of Bolt’s coach, Glen Mills, who suggested at a recent press conference that the time could have been 9.52 seconds or better.

“It all started with an interview with Usain Bolt's coach published in the general media before a Golden League competition in Zurich,” Eriksen told PhysOrg.com, adding that he and his co-authors all share a general interest in sports. “He claimed that Bolt was on track for a 9.52-second record, had he not slowed down. Then it struck us that, given reasonable video footage of the race and some assumptions about his acceleration, it should be possible to ‘calculate’ what that time would have been.”

To arrive at their estimate, the Norwegian scientists analyzed different videos of the race from NBC, the BBC, and the Norwegian Broadcasting Company (NRK). A moving camera positioned on a rail along the race track served as a standard ruler, since the scientists could count the evenly spaced bolts on the rail to track the distance and align these ticks with the runners’ positions.

The scientists made two estimates based on different assumptions. The first and more conservative estimate assumed that Bolt could have maintained runner-up Richard Thompson’s acceleration during the end of the race. The second estimate assumed that Bolt could have maintained an acceleration 0.5 m/s2 faster than Thompson.

Based on their recording of Bolt’s and Thompson’s positions at the times they passed the ticks on the rail, the researchers determined an approximation of the runners’ positions as a function of time, as well as their speeds and accelerations.

By extrapolating these trajectories to 100 meters, the scientists got their results. If Bolt had maintained Thompson’s acceleration, his time would have been 9.61 ± 0.04 seconds. If Bolt had maintained an acceleration 0.5 m/s2 faster than Thompson, his time would have been 9.55 ± 0.04 seconds.

“For fun, we thought we might as well post the study on astro-ph, an archive for astrophysicists, more or less as an internal joke in the community,” Eriksen said. “However, when we started writing, we suddenly realized that this might actually be interesting and useful to more people than the originally intended audience, and we shifted to a semi-serious approach, and wrote up a ‘real’ paper. In particular, we figured this could be an interesting example of simple physics for educational and outreach purposes, and we therefore submitted the paper to the American Journal of Physics.”

As Eriksen emphasized, this study is a piece of “fun physics,” and its conclusions should not be regarded too seriously. The physicists explained that their estimates of Bolt’s potential time have a 95% error (± 0.04 seconds), but the uncertainties due to the assumptions on Bolt’s acceleration are at least as large as the statistical uncertainties. For instance, the physicists had to calibrate measurements regarding missing ticks on the rail, the precision of the screen clock, and the difference between the screen and stadium clocks.

Another potential uncertainty is the possibility that Bolt may have been tired at the end. (However, as the scientists note from an admittedly subjective perspective, “judging from his facial expressions as he crossed the finishing line, this doesn’t immediately strike us as a very plausible hypothesis.”)

Wind speed is another factor, although the measured wind speed on the track during the Beijing race was negligible. But the physicists noted that favorable wind conditions, such as a 2 m/s wind speed, could decrease the time by as much as 0.1 seconds. With these results in mind, they suggest that Bolt is capable of setting a new world record of less than 9.5 seconds in the near future – but they still reserve some scientific caution.

“I should also say that this study is really pretty much useless for actually predicting the new world record,” said Eriksen. “Taking into account both uncertainties due to assumptions and measuring errors, a proper 95% confidence interval is something like 9.51 to 9.65 seconds – and that's something most people could have guessed very easily. However, the main point is that this is a fun example of simple physics that is interesting to many people. So its main purpose is really for popularizing physics – not to define a new world record. That being said, we do believe that the methods we use are appropriate, and with better data we could have done a lot better.”

More information: Eriksen, H. K.; Kristiansen, J. R.; Langangen, O.; and Wehus, I. K. “Velocity dispersions in a cluster of stars: How fast could Usain Bolt have run?” arxiv:0809.0209v2. Submitted for publication in the American Journal of Physics.

Copyright 2008 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com

Explore further: Dating apps are changing US courtship rituals

Related Stories

Dating apps are changing US courtship rituals

July 29, 2015

From adulterous middle-aged marrieds to millennials who say only freaks chat up people in bars, millions of Americans are finding love online as technology corners the market in romance.

What causes lightning?

July 10, 2015

Thunder and lightning. When it comes to the forces of nature, few other things have inspired as much fear, reverence, or fascination – not to mention legends, mythos, and religious representations. As with all things in ...

Shark's unique trek could help save the species

July 5, 2015

Her name is Jiffy Lube2, a relatively small shortfin mako shark that, like others of her kind, swims long distances every day in search of prey and comfortable water temperatures.

Working out in artificial gravity

July 2, 2015

Astronauts on the International Space Station (ISS) have a number of exercise options, including a mechanical bicycle bolted to the floor, a weightlifting machine strapped to the wall, and a strap-down treadmill. They spend ...

Recommended for you

Innovations from the wild world of optics and photonics

August 2, 2015

Traditional computers manipulate electrons to turn our keystrokes and Google searches into meaningful actions. But as components of the computer processor shrink to only a few atoms across, those same electrons become unpredictable ...

Rogue wave theory to save ships

July 29, 2015

Physicists have found an explanation for rogue waves in the ocean and hope their theory will lead to devices to warn ships and save lives.

Researchers build bacteria's photosynthetic engine

July 29, 2015

Nearly all life on Earth depends on photosynthesis, the conversion of light energy into chemical energy. Oxygen-producing plants and cyanobacteria perfected this process 2.7 billion years ago. But the first photosynthetic ...

Quantum matter stuck in unrest

July 31, 2015

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

Robotic insect mimics nature's extreme moves

July 30, 2015

The concept of walking on water might sound supernatural, but in fact it is a quite natural phenomenon. Many small living creatures leverage water's surface tension to maneuver themselves around. One of the most complex maneuvers, ...

10 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Duude
3.7 / 5 (6) Sep 11, 2008
Additionally, he ran his 200 meter world record which was seen by most as the least likely record to be broken, into a 1.4m headwind.
Noumenon
4.8 / 5 (49) Sep 11, 2008
What are you talking about defunct?

Doesn't seem like he cares as much as you,...

http://www.youtub...pPaCIG0g
DoctorKnowledge
3.4 / 5 (7) Sep 12, 2008
Great article. Grieves me in a new and different way. Had me thinking. Can't beat that.

People aren't machines. If the guy's goal was winning, then he accomplished his goal. His goal wasn't your goal? So what. Did anyone ask him his goal? Maybe he was enjoying the moment of being so far ahead, he could afford a gesture.

Scientists? Or sports announcers? Speculating on what if he'd had more breakfast? Whether he should have stepped slightly to the side at time 4:31?

It would be helpful if the emotional idiots in science would hand in their badges, and take up their true destiny as lead writers for "The National Enquirer".
Mayday
3.2 / 5 (5) Sep 12, 2008
I like that he goes out there and has some fun with it. I personally find his "performance" to be a very good role model. It inspires me. We should all try and enjoy life, especially while doing the very things we are good at. I'm quite tired of the down in the mouth , all serious and poutty mouthed affectations that many modern atheletes bring to the field. They should give me a break.

I laugh out loud almost every morning at the gym to watch my fellow physical aspirants dourly frowning through their workouts. I find it fun. And the endorphins make me smile. If you don't enjoy it, then find a workout or physical activity that you can enjoy.

To the real competetive atheletes: You could all learn something about life from the guy who runs, wins and loves life along the way!

To the scientists who are hoping to turn him into a machine: please strap on those golden shoes yourself and give it a try, smartguy! There are plenty of empty running tracks out their so I'm sure you can find a lane with your name on it.

Good luck with that!
Modernmystic
3.1 / 5 (8) Sep 12, 2008
Actually I think the fastest man on Earth has gone roughly mach 25.

We're creatures of the mind, not muscle. While I'm sure this is somehow interesting to some folks I honestly could care less either way.
nano999
3 / 5 (4) Sep 12, 2008
@Modernmystic - I second that.
Mayday
2 / 5 (6) Sep 12, 2008
Whoa. Pushing our physical prowess, strength and endurance will always be part of human striving. And though we may use "rocket science" to leave the planet, our body's physical abilities and limitations will not be left behind.

You might want to speak to an astronaut about it a little.
zevkirsh
2 / 5 (2) Sep 13, 2008
THEY HAVE IT ALL WRONG...he would have been at least 6 centimeters ahead of that position they calculated. my own simulations confirm this.
Sonhouse
1 / 5 (1) Sep 13, 2008
Actually I think the fastest man on Earth has gone roughly mach 25.

We're creatures of the mind, not muscle. While I'm sure this is somehow interesting to some folks I honestly could care less either way.
Actually I think the fastest man on Earth has gone roughly mach 25.

We're creatures of the mind, not muscle. While I'm sure this is somehow interesting to some folks I honestly could care less either way.
Sonhouse
1 / 5 (2) Sep 13, 2008
That would be pretty fast for him to have run at mach 25 on earth. I would have thought he would burn up a lot sooner than that. When the shuttle returns it is only doing about mach 18 or so and you saw one burn up so I am sure he didn't run mach 25 on earth. Besides how would you even measure it? His time in the 100 meter event would have been about 12 milliseconds so I am sure they couldn't measure it very well....

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.