2008 was a great year for sports fans, with highlights including Usain Bolt shattering both the 100m and 200m world records at the Beijing Olympics and knocking tenths of a second off each in the process. The fact is that athletes have been getting faster and faster since times have been accurately recorded, but is there an upper limit to how fast athletes can run?
American marathon runner Mark Denny, from Stanford University, thought that there were and set about trying to predict what those limits were. To do so he scrutinised the running performances of humans and two other famous racing species, greyhounds and thoroughbred horses, to find how close their modern participants are to the peak performances for their species.
He has just published his predictions for their top speeds in The Journal of Experimental Biology.
Having found records dating back to the 1920s for dogs and the 19th century for humans and horses, Denny looked to see whether there were any clear trends. Were they all still improving or 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 racehorses and greyhounds have indeed already reached a plateau. There has been no improvement in the speed of either the thoroughbred racehorse or dogs since the 1970s although he concedes chance might still turn up a faster animal.
For humans, the results were complicated by the wide range of different distances over which people compete. Looking at the speeds of male race winners through the years, it appears men still haven’t reached their top speeds at any distance and Denny predicts that male 100-metre sprinters could one day get the record down to an incredible 9.48seconds.
However the top annual speed for female sprinters levelled off in the 1970s, but Denny suspects that female sprinters still have room for improvement too and predicts that they could eventually knock more than 0.4seconds off the current 100m world record.
Looking at marathon runners, Denny predicts that males could cut the current world record, held by Haile Gebrselassie, by up to 4 minutes 23 seconds and female marathon runners could eventually complete the 26miles, 385 yards (41.195 km) in 2hours 12minutes 41seconds. He adds that Paula 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.
Whether his attempts to calculate the absolute limits of athletes’ speeds are correct, only time and times will tell. However, he emphasises that we have no idea what aspect of physiology will eventually restrict runners’ performances from improving and is keen to find out just what it is that will prevent future gold medal winners from breaking his predicted limits.
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