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Just how fast can a human run? Just how fast can a human run?
(10 minutes later)
By Pallab Ghosh BBC News science correspondent Usain Bolt has re-defined what is possible on the trackBy Pallab Ghosh BBC News science correspondent Usain Bolt has re-defined what is possible on the track
Usain Bolt set new world records for the 100 and 200 metres at the World Championships in Berlin a few weeks ago. His achievements have raised the question: how fast can a man run?Usain Bolt set new world records for the 100 and 200 metres at the World Championships in Berlin a few weeks ago. His achievements have raised the question: how fast can a man run?
In 1968 an American Jim Hines became the first man to break the 10 second barrier in the 100 metre sprint.In 1968 an American Jim Hines became the first man to break the 10 second barrier in the 100 metre sprint.
The record was chipped away at steadily until Usain Bolt burst upon the scene.The record was chipped away at steadily until Usain Bolt burst upon the scene.
Since then the record has tumbled race after race: From 9.72 in May 2008 to 9.69 three months later to 9.58 last month.Since then the record has tumbled race after race: From 9.72 in May 2008 to 9.69 three months later to 9.58 last month.
The sprinter himself thinks he can run the race at 9.4 seconds.The sprinter himself thinks he can run the race at 9.4 seconds.
Analysts agree that he can improve his performance.Analysts agree that he can improve his performance.
He still slows down at the end of the race when he knows that he has won by a clear distance, his overall technique could still be refined and crucially he has not run the race with the legally allowed fair wind behind him.He still slows down at the end of the race when he knows that he has won by a clear distance, his overall technique could still be refined and crucially he has not run the race with the legally allowed fair wind behind him.
But what is the ultimate best time for the 100 metres?But what is the ultimate best time for the 100 metres?
Very tallVery tall
At 6ft 5ins (1.96m) Bolt is much taller than other Olympic sprinters who are normally between 5ft 9ins (1.75m) and 6ft 3ins (1.9m).At 6ft 5ins (1.96m) Bolt is much taller than other Olympic sprinters who are normally between 5ft 9ins (1.75m) and 6ft 3ins (1.9m).
For athletes any taller it had been thought that any additional benefit from a longer stride would be outweighed by their greater bulk.For athletes any taller it had been thought that any additional benefit from a longer stride would be outweighed by their greater bulk.
Some scientists have speculated that Bolt might have more so-called "fast twitch" muscles fibres for a man of his height.Some scientists have speculated that Bolt might have more so-called "fast twitch" muscles fibres for a man of his height.
These provide sprinters with the bursts of power they need for fast acceleration.These provide sprinters with the bursts of power they need for fast acceleration.
But others have suggested that taller men simply have not been attracted to athletics, preferring to devote themselves to more lucrative sports such as basketball or American football.But others have suggested that taller men simply have not been attracted to athletics, preferring to devote themselves to more lucrative sports such as basketball or American football.
According to Raphael Brandon, of the English Institute of Sport, more tall powerful athletes might now be inspired by Bolt's example and be drawn to sprint events.According to Raphael Brandon, of the English Institute of Sport, more tall powerful athletes might now be inspired by Bolt's example and be drawn to sprint events.
That may well bring the time down yet further.That may well bring the time down yet further.
To do it the human body will have to be able to cope with more forces placed upon it.To do it the human body will have to be able to cope with more forces placed upon it.
But the key limiting factor, he says, is that sprinters have to have their feet on the ground for a proportion of the time to generate their pace.But the key limiting factor, he says, is that sprinters have to have their feet on the ground for a proportion of the time to generate their pace.
"There will just come a point where to run any faster you would have to spend so little time on the ground that you would not be able to generate the speeds." "I think there will come a point where to run any faster you will have to spend so little time on the ground that you won't actually be able to generate the speed."
Mr Brandon believes that it is highly unlikely that anyone will be able to run faster than 9.2 seconds.Mr Brandon believes that it is highly unlikely that anyone will be able to run faster than 9.2 seconds.
But he is the first to admit that in athletics people have been suggesting limits which have been subsequently been smashed for generations. But he is the first to admit that for generations people have been suggesting limits for athletic events which have been subsequently been smashed.