Are Track Measurements and Records Accurate?

Anybody who knows me knows I'm a track and field geek (used to compete a lot more, but haven't since my back surgery). So when I came across this story on Slate, I was certainly intrigued.

The Jamaican sprinter Asafa Powell set a new world record for the 100-meter dash on June 14, with a time of 9.77 seconds. The previous record, set by American Tim Montgomery, was 9.78 seconds -- just one-hundredth of a second slower. How accurate are the devices used to time these events?

They can record to the ten-thousandth of a second, although that level of precision is not commonly used. That's because every track (and every lane) differs in length by a minuscule amount, so two runners who race at exactly the same speed might cross the finish line with times that differ by a tiny fraction of a second. In the 1972 Olympics, for example, two swimmers finished a 400-meter race within two-thousandths of a second -- or a few millimeters -- of each other. As it turned out, each lane of the swimming pool had been constructed to a precision of just 10 millimeters, so there was no way to determine the winner.

Luckily I raced longer distances where a centimeter ain't going to matter worth a damn, but I can see this being a problem in shorter events.

Posted by Jake on 06/29/05 @ 05:14 PM
Posted in Interesting | 2 Comments | Permalink

2 Comments

brian said on 07/06/05 @ 09:59 AM:

...was 9.78 seconds -- just one-hundredth of a second slower. How accurate are the devices used to time these events?

They can record to the ten-thousandth of a second, although that level of precision is not commonly used.

10/1000th of a second is the same as 1/100th of a second.

Andrew Hecker said on 06/08/09 @ 11:40 PM:
To that level of precision, there are lots of possible errors built into the system. First and foremost, the finish camera takes a picture, one vertical pixel wide, of the finish line every (if it is in that mode) 1/10000th of a second. But where is the camera aimed? Seeing a single pixel width on the monitor, you can only tell when you are somewhere on the finish line (it is a different color from the track) which is at least 5cm wide. You can't tell if you are on the front of the line, back of the line or even shooting diagonally across it. The rough, always temporary, methods of set up are also not that precise. A few hours or less before the meet, people are using plumb bobs and their reckoning to position that camera--its close but never "perfect."

To view the time, the computer takes those individual vertical pixel lines and lines them up next to each other, with the time stamp attached. It is left up to the human eye to determine, where the torso of the human being is. If the exposure is not correct, or even if the detail is not visible, you are depending on the human interpretation of the image, the opinion of where the torso begins and ends for them to click on a particular line to deduce the time. It is a good system, the best we have in the price range, but it is not perfect.

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