(Reuters) - South African "blade runner" Oscar Pistorius has unleashed a debate about disabled sport with an emotional claim that a rival in the T44 200 meters final at the London Paralympics beat him thanks to longer prosthetic legs.
Pistorius had not been beaten over 200m for nine years, but the result of Sunday's final was less of a shock than the post-race outburst of a man who is the face of disabled sport partly thanks to his dignified campaign to be allowed to challenge able-bodied runners at the Olympics.
"The size of some of the other guys' legs are unbelievably long," Pistorius told Britain's Channel 4 television.
"We're not racing a fair race. The International Paralympic Committee (IPC) have the regulations, but the regulations allow the athletes to make themselves unbelievably high."
Besides detracting from the victory of Brazil's Alan Oliveira, it was a surprising rant from a man who had convinced sports administrators that his own carbon-fiber blades gave him no advantage over able-bodied runners.
So can Paralympic medals be decided by the length of an artificial leg? And where does that leave a branch of sport striving to be taken as seriously as able-bodied sport?
If Pistorius has a case, it is certainly not that Oliveira's longer blades give him a longer stride.
South African-based sports scientist and coach Ross Tucker pointed out on his blog "The Science of Sport" that Oliveira took 98 strides to Pistorius's 92.
John Brewer, Director of Sport at the University of Bedfordshire in Britain, said the advantages of longer blades were not clear.
"With any lever, the length could leverage more force, but I also suspect that longer blades would increase instability," he said.
Pistorius accepts Oliveira's blades were legal. This means Pistorius could also have used them, if he had been prepared to change from the blades that he was authorized to wear against able-bodied runners at the London Olympics four weeks ago.
"This situation may be a reason to force Paralympians to use the same kind of technology, while of course adjusting to their individual body types," said Andy Miah, Director of the Creative Futures Institute at the University of the West of Scotland.
"The big question emerging from the T44 200m final is whether the Paralympic rules need to be tighter ... If Oliveira's prosthetic legs are bigger and better and legal, then Pistorius really ought to get some."
But how to tighten the rules?
Pistorius was born without proper lower legs. It might be possible to work out the leg length of an average person with Pistorius's upper body, but Pistorius is not average.
"In elite athletes ... the ranges that you'd find in the normal population don't apply," Tucker wrote, adding that Oliveira may just have been catching up with Pistorius in finding his personal optimal blade length.
"If you're wondering about whether Pistorius has a valid argument, then welcome to the slippery slope that is the introduction of technology with no clear answers to the sport."
So can the Paralympics be credible on that basis?
"The media sometimes focus on the technology when they shouldn't," said IPC spokesman Craig Spence.
"You could say that the fact that Oscar Pistorius has attracted such media attention is a positive for Paralympic sport. The negative aspect is that the story overshadowed some terrific other performances in the stadium."
In many ways, he says, it means disabled sport is becoming mainstream as big audiences increase the pressure for transparency and fairness.
"Serious sport has big controversies ... This debate shows how seriously we want to be taken," he added.
For all its stories of personal struggles against adversity, disabled sport has never been immune to rule-bending and cheating, but has learned to adapt as mainstream sport has.
Doping is not unknown, and drug testing is systematic - although not as extensive as at the Olympics.
"Boosting" is the practice by some wheelchair-bound athletes of using self-harm to get the higher blood pressure and endurance that other athletes can achieve naturally. It is considered dangerous and banned, but is hard to test for, and has probably not been eradicated.
Athletes with intellectual impairment were shut out of the Paralympics entirely for 12 years after a Spanish basketball team faked their impairment to win gold in Atlanta.
Events are now being reintroduced slowly with tougher testing, but the complex classification of physical disabilities to allow meaningful competition regularly generates controversy.
In London, U.S. swimmer Mallory Weggemann was left fuming after having her classification changed from S7 into the less disabled S8 class on the eve of the Games. She reluctantly accepted the ruling and went on to win the S8 50m freestyle gold. Her compatriot Victoria Arlen had to appeal to be allowed to swim after being declared ineligible days before her event.
The system remains hard to grasp. But London's ecstatic spectators seem completely unperturbed by the fact that there are no fewer than 15 men's 100m finals, or that swimmers with two arms can compete against others with one arm or even none.
With 2.5 million tickets sold, the Games are a sellout.
Events have been shown in more than 100 countries. The host broadcaster Channel 4, which for the first time paid for the rights, has expanded its coverage in response to high ratings. Some 5,500 journalists and broadcasters are covering the Games.
The event has become a draw to sponsors and television advertisers. If disabled athletes are stretching the rules and the technology, it is not least because a number of them, not only Pistorius, can now earn a living from sport.
Spence says the IPC will continue to do its best to ensure a level playing field, but adds: "Athletes are getting faster because more and more of them are going full time and putting in six days a week of training.
"Oscar Pistorius has taken 2.5 seconds off his personal best in the time that he's had those blades, and that's not because of technology, that's down to hard work."