Usain Bolt, the world's fastest man, could possibly run 9.4 seconds over 100 metres at this year's London Olympics, Games organising committee chairman Sebastian Coe said on Wednesday.
Asked about media reports that Bolt was planning an assault on his world record of 9.58 in London, Coe told Reuters that Bolt had the ability to tear up the laws of physics.
"I do seem to remember scientists telling people if they tried to break the four-minute mile, they would probably die in the process," the twice Olympic 1,500 metres gold medallist said in an interview.
"I remember scientists telling me it was probably unlikely that anybody would run significantly under 1:43 for 800 metres," added Coe, whose world record of 1:41.73 stood for 16 years.
"David Rudisha (the Kenyan 800 metres world record holder) is quite capable of running a chunk under 1:41.
"I do think it's possible (for Bolt to run 9.4) but also having watched the extraordinary performances of Yohan Blake, his countryman...
"And Tyson Gay in the States is not going to be a pushover either. I'm absolutely convinced that Usain can run faster, but this will be a Games that's very competitive at 100 and 200."
Despite his zero-tolerance stance towards doping, Coe said it was dangerous to treat every superhuman performance as suspicious because of a disgraced minority of cheats.
"Nobody comes from nowhere," he said. "Usain Bolt has been around a long time working very hard.
"It's far too easy to simply say 'they've made rapid and dramatic progress and therefore they're on some kind of illegal supplement'. That's rarely the case.
"I broke 12 world records and won two Olympic titles and would no more have jumped off Beachy Head than taken any supplement."
Coe said he would accept the ruling over banned British sprinter Dwain Chambers, expected in April, by the Court of Arbitration for Sport (CAS).
CAS rule on an appeal by the British Olympic Association (BOA) against a decision by the World Anti-Doping Agency (WADA) that its lifetime Olympic bans are illegal.
"We would have to live with it (if overturned)," said Coe, an advocate of life bans. "I have written in support of the BOA as has the Minister of Sport.
"It was a mistake to move (bans) from four to two years.
"Had we stayed at four years this would have been an academic discussion because a four-year ban would have meant the loss of an Olympic Games in that four-year cycle.
The BOA currently bans from future Olympics any British athlete, such as Chambers and cyclist David Millar, found guilty of a doping offence.
WADA rules specify a maximum two-year ban for a first offence.
"I don't think two years is enough," said Coe. "It's cheating. People talk about rehabilitation, that kind of stuff, but I'm not convinced.
"The damage is done to the integrity of sport, the confidence for people going to sport, for competitors, it's really vital that we control this.
"I do not think anybody at the highest level of sport that passes beyond that border of morality is doing so because they don't understand the implications.
"If you take something that enhances your performance you are basically forfeiting your place in the sport."
With Britain looking set to undershoot its Olympic budget, Coe defended the London Organising Committee over ticket prices as it tries to balance its two billion pound operating budget.
"We start off with a liability of two billion pounds. We have to raise that money ourselves," he said, asked about top seats for the men's 100 metres final which will cost 750 pounds.
"Two thirds of the tickets are affordable at 50 pounds or less.
"Only eight percent of tickets are in the hands of the sponsors, which is low considering their contribution of one billion pounds."