Olympics: Sprinter reaction time question

[CJJ]

(This is sports-related, but has more to do with science than sport; mods feel free to move it if you see fit)

This article from Livescience piqued my curiosity. It contains the following statement:

Scientists studied reaction times of sprinters in two races at the 2004 Olympics and found that those closest to the starter had significantly faster reaction times out of the blocks. The average reaction time for sprinters in lane 1, nearest the gun, was 160 milliseconds. The average time for all other lanes combined was 175 milliseconds.

The article mentions that sprinter and non-sprinter reaction times were measured against the volume of the starting gun–under the presumption that the sprinter in lane 1 gets a louder starting signal than the others–and a correlation was found.

My question is, aren’t they missing an obvious cause? The speed of sound is ~1056 ft./sec. so the starting shot travels about 15 feet in 15 milliseconds. With about eight sprinters, I’d wager the sprinter in lane 5 (average of 2-8) starts about 15 feet away from the lane 1 sprinter.

I find it incredible they would miss this, so there must be something about sprint racing I don’t understand. Perhaps all the blocks are electronically wired for sound such that the sound from the starting gun reaches a speaker behind all the blocks at the same time, but then why would the scientists focus on sound volume?

[CookingWithGas]

I don’t know why they focused on volume, but they controlled for other variables and volume certainly seems to be a factor.

So the researchers did a test. They had four trained sprinters and 12 untrained participants perform sprint starts from starting blocks modified to measure horizontal force. Using a recorded gunshot as the ‘‘go’’ signal, they randomly presented the signal to test subjects at various decibel levels, from a low of 80 dB to a high of 120 dB.

The louder the gunshot, the faster the reaction time of the test subjects.

Although the speed-of-sound theory is worth pursuing the cognitive aspects seem to be valid to me as not-even-a layman.

[blinkingblinking]

Maybe the the ones in the middle lanes are more likely to be drug takers and cheats and that slows their reaction times even though the drugs make them faster overall.
Thanou is an interesting case

http://en.wikipedia.org/wiki/Ekaterini_Thanou

[KarlGauss]

I just checked the original article. They controlled for the speed of sound by placing a loudpseaker 30 cm from each runner’s ear, with said loudspeaker giving the “Go” signal .

Nice try.

[blinkingblinking]

it says “lane assignments are chosen by a drawing.” I thought the fastest were given the middle lanes and the slowest on the outside lanes.

[CJJ]

@KarlGauss

I just checked the original article. They controlled for the speed of sound by placing a loudpseaker 30 cm from each runner’s ear, with said loudspeaker giving the “Go” signal .

Nice try.

Suppose they also play a loudspeaker at each starting block during Olympic sprint races. If so, how does lane 1 always get a louder signal?

Suppose they don’t do this in Olymic races; all sprinters hear the same gun. If so, how does quicker cognitive recognition of louder sounds compare to the delay caused by the speed of sound itself? Do they factor the speed of sound from the starter gun into the staggering of lane positions?

[Clockmaker]

@CJJ

(This is sports-related, but has more to do with science than sport; mods feel free to move it if you see fit)

This article from Livescience piqued my curiosity. It contains the following statement:

The article mentions that sprinter and non-sprinter reaction times were measured against the volume of the starting gun–under the presumption that the sprinter in lane 1 gets a louder starting signal than the others–and a correlation was found.

My question is, aren’t they missing an obvious cause? The speed of sound is ~1056 ft./sec. so the starting shot travels about 15 feet in 15 milliseconds. With about eight sprinters, I’d wager the sprinter in lane 5 (average of 2-8) starts about 15 feet away from the lane 1 sprinter.

I find it incredible they would miss this, so there must be something about sprint racing I don’t understand. Perhaps all the blocks are electronically wired for sound such that the sound from the starting gun reaches a speaker behind all the blocks at the same time, but then why would the scientists focus on sound volume?

I was shocked as well and did some math on this. I am using 1126 feet per second for the speed of sound in my calculations, and I assume 1.225 meters as the average track width. This gives lane 1 nearly 25/1000th seconds (0.024985082) time advantage over lane 8.

The perfect solution is to use multiple gun sounding devices; place each of them one meter directly behind the runner and place 1 more in an imaginary lane directly next to the inside and outside lanes. Olympic tracks actually have 9 lanes (lane 9 usually goes unused) and so 11 sound devices. With this there is zero advantage, all lanes are equal.

The next best solution is to provide a sound device in the middle and the outside lanes so they are all equal distant from their nearest runner. This reduces the greatest delay to just 1 lane difference for 8 lanes and 1.5 for 9 lane races. This is just 3.6 to 5.35/1000ths of a second different; much better than 25!

A sound device place on both ends of the races offers a maximum delay difference of 10.7/1000ths.

and if a single sound source absolutely must be used, then it would be far better to place it directly behind the runners in the middle lane; the further away the less difference between runners receiving the sound. Distances behind the runners of 8m (31.6 ft), 12m (47.2 ft), and 22m (86.6 ft) reduces the maximum delay difference to: 2.68, 1.8, and 0.98/1000th’s respectively.