Timing Technology Behind Olympic Record Results

An anonymous reader writes "We've been on the edge of our seats cheering on the athletes at the Beijing Olympic games — but so often do athletes' victories and defeats rely on accurate timing. As the athletes compete on the world stage behind the scenes technology records their results. This interview with Omega's Christophe Berthaud (video) — the company's 23rd time as official Olympic timekeeper — explores how far the technology has come since the first time it was used in 1932."

Comments

Re:Not accurate. Consistent.

[oldspewey]

also track (maybe on the blocks to see who actually is leaving first)

This is already done - they no longer rely on human judging to determine false starts

Lost in translation...

[HonkyLips]

The guy mentions several times that the camera takes 2000 frames per second, but unfortunately states that this gives a precision of "two thousandths" of a second. The actual precision would be "one two-thousandth" of a second... I suppose this is an understandable translation error. But I enjoyed the piece, I was interested that they used a GPS signal to synchronise their systems.

Re:The photo/camera finish was totally inconclusiv

[LordKronos]

Inconclusive? You could clearly see a gap between cavic's finger and the wall. Whereas phelps fingers were bent back a bit from contacting the wall.

http://sportsillustrated.cnn.com/multimedia/photo_gallery/0808/oly.phelps.sequence/content.5.html

Re:Why the difference?

[uberdilligaff]

I have officiated swimming competitions for nearly 20 years, and LordKronos has it exactly right. Both USA-Swimming and FINA (international swimming governing body) rules require that races be decided by accurate electronic timing precise to 1/100 sec, and no more. Further precision to 1/1000 sec is neither desired nor permitted, and by rule, swimmers who have the same time to the nearest 1/100 sec are tied and share equally in the place. At the velocity of Olympic swimmers (Phelps' 100 fly averaged 1.98 meters/sec), the .01 sec time difference amounts to a 2cm margin of victory.

The clock stops when the pad is first touched

[h2_plus_O]

according to fucking rules, you need to press the sensor(s) with both hands, eh? That's why people complained about the lack of frame(s) which show that moment.

Actually, his post is correct. The clock stops when the sensor is touched by that first fingertip- and Phelps clearly made it to the wall first by that measure. The camera and the electronic sensors agree on this.
The decision as to whether or not he did it according to the rules is a separate one. The rules for butterfly require that your shoulders be level, that your arms come around symmetrically and above the water, and that you touch the wall with both hands at the same time- but there are allowances for slight imprecisions in this regard, and Phelps was well within those tolerances. What the judges would look for is whether Phelps galloped his stroke (i.e., brought his arms around significantly assymetrically), if he would have stroked with one hand while lunging with the other, if he'd lunged over on one side, or if he'd kicked assymetrically in such a way that would get him some advantage. He did none of these things- at the finish, his body is straight, his shoulders and hips are level and square, his feet together.

What this came down to was stroke timing. Once you commit to the glide phase of a butterfly stroke, you can't break that straight-armed glide position unless you stroke through past your shoulders and recover both hands forward above the water. Approaching the wall, the two swimmers were out of phase with each other, with Phelps gaining ground- in such cases, it's always a matter of some strategery to time your stroke most advantageously, since in that drive phase of the stroke your hands can't reach forward to the wall and you're decelerating in your glide phase. Cavic stretched his last glide/lunge really well- given where he was in his stroke cycle, it wouldn't have made much sense to take another stroke. Phelps, on the other hand, was more than half-a-stroke away from the wall at the point where he needed to decide whether to take another one, so essentially he didn't do any gliding in- he touched the wall on the down-beat drive phase of his stroke, just barely in time to out-touch Cavic.

From what I can see, (based on having swum competitively for 20 years) I agree with the result- Phelps clearly won, if only by a very teeny margin.