Vayer power-to-weight theory sparks controversy

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Controversy is in the air at the 100th Tour de France amid claims by a prominent former coach that riders who dope can be detected simply by calculating the power generated while on their bikes.

Antoine Vayer, a coach at the Festina team between 1995 and 1998, has used maths and physics to calculate a rider’s power, which is measured in watts.

The results provided make for irrefutable proof in the eyes of some, but are dismissed by others.

“Analysing power helped me to optimise training (at Festina) but also allowed me to observe the effects of doping,” Vayer said.

“In certain race situations it is clear that a rider should not be able to use as much power.”

Vast swathes of data are used to make his calculations — from the length of a race to the weight of a rider and his bike, air resistance, gravity and air density — and help bring the performances of riders of all body types together. However, the weight of 78kg is taken as a benchmark.

Vayer’s work has led him to consider that there is a threshold beyond which the performances of a rider are abnormal — at 410 watts, he says, a performance is considered “suspicious”, at 430 watts it is “miraculous” and at 450 watts it is “humanly impossible”.

As an example, during his record-breaking ascent of the Alpe d’Huez in 1995, Marco Pantani produced 468 watts, while Lance Armstrong registered 455 watts cycling the Hautacam in 2000 and Alberto Contador 491 watts on the Verbier in 2009.

Vayer says his work should be considered as an alternative to attempts to detect doping offences using traditional testing methods, which can sometimes miss certain substances, such as EPO during the 1990s.

“Using watts does not reveal the cause but rather the consequence of doping,” he says.

His figures, published by the press worldwide, have sparked controversy.

“It’s pseudo science,” dismisses Team Sky principal Dave Brailsford. “In our team, we can already see how difficult it is to get precise and direct data (gathered from power meters on bikes) which we can use.

“To do it from distance is even more complicated. To trace a line through a moment in history and say, ‘Beyond that is doping’ is a rather dramatic way of thinking. “The history of human sport has shown that you can go faster by your own means.”

David Millar, who was arrested in 2004 for possession of doping products and served a ban before eventually returning to the sport, said: “It is a useful tool. The methodology is not perfect — it gives an idea but you cannot say that it’s black and white.”

Meanwhile, Frederic Grappe, a French coach and biomechanical researcher says that fixing a threshold and declaring that anything beyond that is doping is “scientifically and intellectually dishonest.”

“Antoine Vayer wants us to believe that he has come up with an infallible technique to detect drug cheats,” he said.

“These are basic equations of physics, it is not pioneering. The problem is knowing how to interpret these things. You cannot say that, because someone goes beyond 410 watts, he is doped.”

Grappe also believes that his methods are not completely reliable.

“Between a 20-minute push like Verbier and a one-hour climb like the Tourmalet, there is a difference, and altitude is a factor too. His results are accepted and nobody verifies them.”

“The thresholds are very generous,” retorts Vayer. “At 410 watts, in other words according to the laws of physiology, you have the best athlete in the world who we have never seen before.

“Our indirect calculations are shown to be exact. Our margin of error is two percent. We receive direct data, like from (Jurgen) Van den Broeck, who was fourth on last year’s Tour. We compared that to what we had done and we were less than one percent out in our calculations.”

On this year’s Tour de France he will collect data from six “hill radars” with the first of those on the climb to Ax 3 Domaines, scheduled for Saturday.

The data from those should add to the controversy while the researchers wait in the hope that all riders will publish their own data, validated by independent laboratories, in order to create a concrete basis from which to work.

Text via AFP.

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