Power data debate heats up at Tour de France

Establishing the truth is, however, altogether more complicated.

Frenchman Antoine Vayer, who was a coach at Festina when the infamous EPO scandal broke in 1998, says it is possible to know who is cheating by measuring how much power a rider generates.

Team Sky principal Dave Brailsford, however, is not convinced.

"It's pseudo-science, we have our own data with real validity, people can create their own theories and we understand how difficult to get accurate information is and so to do that from afar is very difficult," Brailsford, who declines to make his riders' data public, told reporters.

The calculation is reliable. It is the interpretation that is subject to debate.

"Nobody invented that method of calculation. It is pure physics," Julien Pinot, a coach at French team FDJ.fr, told Reuters.

"It is a mathematical model that takes into account environmental data such as atmospheric pressure, temperature, weight," the Frenchman, who is Tour de France rider Thibaut Pinot's older brother, added.

Can those calculations give indications that a rider is cheating?

Vayer insists that a performance is "miraculous" if a rider goes beyond the 430-watt threshold, and "inhuman" beyond 450 watts.

"You've got to be careful with all of that," warns Brailsford.

"From a scientific perspective, it's got nothing to do with doping, looking at that data from a scientific perspective, we wouldn't use it as valid information, it wouldn't stack up. So we'll work with the facts and the data and our own information."

The first calculations made from Chris Froome's ascent to Ax-3-Domaines in his Tour de France stage eight win on Saturday shows that the Team Sky rider generated about 433 watts - the third best performance of all time on that climb.

"Any interpretation is delicate," says Pinot, who would rather use data taken from power metres, which have a "two per cent margin of error on a 30-minute climb".

Usually, those instant calculations are backed by power metre data but setting a barrier beyond which doping is inevitable "makes no sense", according to Pinot.

"It depends if the climb is made at a regular speed or in fits and starts, if it's part of a succession of ascents or not. Some do not make the difference," he explains.

Brailsford finds such theorising crude.

"You've got to be careful, because at some point if you draw a line in the sand and say above that point there is doping and below that point there is not doping, it's a very, very crude way to think about something," he said.

Pinot said he would rather look at trends.

"The last thing that struck me is the Tour of Switzerland. In the final time trial, (Portuguese) Rui Costa rode the last ascent (to the Flumserberg) in 30 minutes. In 1995, Marco Pantani rode it three minutes faster and it was on a stage with several climbs, the weather was bad."

Garmin-Sharp manager Jonathan Vaughters also believes a group of riders' climbing times should be looked at, not just the winner's, because to prevail in a Tour de France a rider somehow must push the limits.

Brailsford points out that human nature is such that new ground will always be broken.

"At some point in time the natural progression of the human race will mean riders can ride faster clean, than old guys used to ride 10 or 15 or 20 years ago, doped," the Welshman said.

"That's going to happen. Just to use this one line in the sand and go 'right, he's doping', it doesn't say take into account anything we've seen in the last 100 years of the athletic endeavour of sport, which is people get faster.

"At some point they've got to catch up and that doesn't mean to say somebody is doping."