100meter sprint world record could go as low as 9.48 seconds

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The following might be of interest

Ralph Giarnella MD

Southington Ct USA

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100-meter sprint world record could go as low as 9.48 seconds

2008 was a great summer for sports' fans. World records tumbled at the Beijing

Olympics. Usain Bolt shattered both the 100m and 200m world records, knocking

tenths of a second off each. People have been getting faster and faster over the

last few decades, which made marathon runner Mark Denny, from Stanford

University, wonder whether last century's massive increase in population could

account for these dramatic improvements. He also wondered whether there are

absolute limits on running speeds and, if so, how close are we to them?

Suspecting that there are, Denny decided to scrutinise the running performances

of humans and two other famous racing species, dogs and thoroughbred horses, to

find how close modern runners are to their species' peak performances. He

publishes his predictions for their top speeds on 28 November 2008 in The

Journal of Experimental Biology at http://jeb.biologists.org.

Having found records dating back to the 1920s for dogs and the 19th century for

humans and thoroughbreds, Denny looked to see whether there were any clear

trends; had any of the species' performances already levelled off? Plotting the

annual top running speeds for all three species over the years, it was clear

that racing horses and dogs have already reached a plateau. There has been no

improvement in the thoroughbred's speed in the Kentucky Derby since the 1940s

and two other major US races since the 1970s, while dogs' performances also

levelled out in the 1970s. The increasing dog and thoroughbred populations

hadn't improved the animals' performances. However, 'chance might still turn up

a faster animal,' says Denny and he predicts that thoroughbreds could improve

their top speeds by as much as 1% in the 2012m Kentucky Derby, eventually

peaking at a top speed of just over 17m/s.

For humans the results were complicated by the different distances that people

race. Looking at the speeds of male race winners through the years, it seems as

if men still haven't reached their top speeds at any distance and Denny predicts

that male 100·m sprinters could one day get the record down to an incredible

9.48s, running 0.23m/s faster than Usain Bolt's current world record of 9.69·s.

Meanwhile, female sprinters' top annual speeds levelled off in the 1970s,

suggesting that any improvement in their speed was not due to a population

increase. However, Denny suspects that female sprinters have room for

improvement too, and predicts that they could eventually knock more than 0.4s of

the current 100m world record to cover the distance in 10.19s.

Looking at marathon runners, Denny predicts that males could cut the current

world record, held by Haile Gebrselassie, by between 2min7s and 4min23s. And

when he calculates the top speed that a human female marathon runner could

achieve, Denny suspects that women could eventually cross the 42,195m finishing

line in 2h12min41s. He adds that a Radcliffe's current world record of

2h15min25s is very close to his average prediction for the maximum marathon

speed and suspects that female marathon runners could be the first group to

approach his predictions and test whether they hold.

Denny is pleased to have shown that it is possible to calculate the absolute

limits to speed of running animals ranging from humans to thoroughbred horses.

However, he emphasises that we have no idea what aspect of physiology restricts

runners' performances, and is keen to find out what will prevent future gold

medal winners from breaking Denny's Limits.

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IF REPORTING ON THIS STORY, PLEASE MENTION THE JOURNAL OF EXPERIMENTAL BIOLOGY

AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A LINK TO:

http://jeb.biologists.org

REFERENCE: Denny, M. W. (2008). Limits to running speed in dogs, horses and

humans. J. Exp. Biol. 211, 3836-3849.

Full text of the article is available ON REQUEST. To obtain a copy contact

, The Journal Of Experimental Biology, Cambridge, UK. Tel: +44

(0)1223 425525 or email kathryn@...