In Berlin on Sunday, Usain Bolt set a new world record time for the 100m sprint, the Jamaican completing the run in an astonishing 9.58 seconds - a full 0.11 seconds faster than the previous record. But how did Bolt achieve this run, and how much faster can a person go? To ease myself back into blogging after a conference break, here's a look at the science of Usain Bolt.
You might think that the 100m sprint is just a question of running very fast in a straight line; but there's a lot more to it than that, with five distinct stages to a race: reaction; clearance; acceleration; maintenance; and deceleration.
The first task is to react to the starting pistol. For the average human, reaction times are around 0.200s - 0.250s, to which you would have to add the time taken for the sound waves to reach the athlete - perhaps a further 0.050 seconds. Anything faster than 0.100s is regarded as biologically implausible, and for that reason any reaction quicker than this is considered to be a false start. Athletes can improve their speeds by training themselves to react to the particular stimulus, and so most top sprinters react in about 0.150s, although on the flip side they probably wouldn't be much help in a bank robbery. Bolt's reactions in this race were a fairly unremarkable 0.147s. Actually, he was one of the slowest off the blocks, positively dawdling in comparison to say Tyson Gay.
What happened next was examined in detail by a German Biomechanics Project that happened to be operating in Berlin during the race. For comparison purposes, here's the profile of a typical sub-10s 100m sprint.
You can see the various stages clearly. Explosive force is used to clear the blocks, followed by a period of acceleration that actually takes up the majority of the race. It takes the first 15-20 strides to reach maximum stride length, at which point the sprint - who begins the race leaning forwards - adjusts their centre of gravity back towards their hips. Acceleration continues until a peak speed is reached at about 60 metres, and then the idea to to maintain this speed as long as possible until deceleration inevitably sets in.
The key to hitting these targets is the way that the body uses energy. The race is so short that virtually none of the energy the athlete uses comes from breathing during the race - when the pistol fires, they have all the oxygen in their blood they need. Energy is supplied by the Anaerobic Energy System, which replenishes ATP - the cells' energy centres - through metabolizing first creatin phosphate (ATP-CP), then glycogen in the final seconds as the CP is exhausted. It's at the end of the ATP-CP phase, at around 60m, that maximum speed is reached.
So here are the split times from Usain Bolt's run:
Even without knowing the times, you can see that this is a special run. The first few seconds are fairly average, and as expected the acceleration trails off after around 40m, but then he just keeps going. Bolt covers 60-80m faster than 40-60m, somehow increasing his acceleration, and takes 80-100m at the same speed, with no significant deceleration. It was this endurance in the last 40m that put him in the record books last year. If he stops turning his head about and waving to the crowd; if he reacts a fraction faster to the starting pistol; and if he can perk up the first forty metres of acceleration, who knows how much faster he could go? The man himself says 9.4 seconds. I wouldn't bet against a sub-9.5.
I just hope he's clean...
Fascinating reading, Martin. Thanks!
He doesn't look like he's on drugs. Compare his physique to that of sprinters of a decade ago..., he's quite a slim lanky chap rather than an over muscled powerhouse. I think he's just benefiting from an unusual body shape, like other extraordinary athletes such as Michael Phelps.
Good point, Gimpy.
I think that you are very clearly described, and I did not raise any questions!
Deleted be the hypocrites of the sciences, the obscene hyperbaric odorances in the midst of the lord. you who speak not want not, and ye who want not eat not, yet since the sin of Eve have we witnessed an utterance of such despicable outrageous monotones of earthly destruction as the fall of Man unto hedonistic sin with the invention of the computer and windsocks, so he can but sit back in the lawn chair of parody watching the defeat of the side of good in the longstanding volleyball match deciding Thy purposes of man's intent to mock the Sniffers of Crack, thou steroid eating behemoths who stroll the Earth sprinting meters in defiance of the natural order of the Lbs. of God, who is honestly trying to thin his waistline.
"Amen, Brotha!"
And with this, we move on to the Eucharist of Seriously, Where the Fuck is a Site that Tells You Usain Bolt's Top Speed In The 9.58 Run.
Cranksnortin(3:22): So i the days of Genesis was created a bored 14 year-old, with nothing to do but create and disperse comments of immense rectitude in the Field of Pointlessness, where he was forever doomed to Boredom, and So Moved on To Porn.
A very interesting post. I hate to complain, but I do have two comments.
First, I would recommend avoiding phrases like "used explosive force". This seems to be using force as though it were energy. The biggest problem with this is that it supports the common misused meaning of force.
The other problem is in the last paragraph. You said that Bolt actually increased his acceleration at the end. I think you meant to say that he increased his speed. His greatest acceleration seems to be at the beginning where the slope of the speed time graph is the greatest.
But still a fun read.
I do not like to watch sports and read news about him, too! It seems to me that there are lessons to a much more interesting!
Great study!
By the way, thanks a lot John for this incredibly useless comment.
Martin's blog being called "Usain Bolt: The Science of Running Really Fast" he wasn't going to speak about snail reproduction. Just surprised you read it if you are not interested. By the way you may have some really long day if you spend them reading about things you are not keen on ;-)
Celine - John and Chloe aren't real commentators, so don't waste your time on them. If you hover your mouse over the links by their names you'll see that they are spammers (well, for john's you actually have to click the link to see that he's flogging erectile dysfunction bollocks.
It's a good rule of thumb - if the commetn only relates tangentially to the post and could relate to any post on much the same subject, and if it reads like it was written by somone for whoim emglish is not their first language, then it's probably spam.
Martin - interesting post, I hadn't noticed his 60-80 acceleration before.
Well if we can find more people who are at least 6 and a half feet tall with a ridiculous inseam, mostly fast-twitch muscle fibers, outstanding coordination, strength, flexibility etc., and a desire to work hard then maybe we can reach the absolute limit of speed. Usain Bolt has pretty much all of these, and I doubt anyone will ever challenge his performances for a long time. He is a one in a billion athlete. The chances of finding the next Jordan, Phelps, or Woods are much higher than finding the next Bolt or a medic curing the yeast infection itchy bumps. Track is pretty much at it's limits and it's available to the most people since you don't need a pool or a golf course to train in.
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