PARIS (AP) Making good on a pledge he made in winning the Tour de France, Chris Froome released results of laboratory tests on his body to counter skeptics in France who have repeatedly expressed doubts that he rides clean.
The lab in London measured how efficiently Froome's body uses oxygen, and his power and endurance. The results were published late Thursday on the website of Esquire magazine.
One test of VO2 max, an indication of how effectively the body transports oxygen from the air to muscles during intense exercise, measured Froome at 84.6, more than double what it would be in the general population, the magazine reported.
''Off the charts. We've never had anything close to that in the lab,'' it quoted one of the lab's sports scientists, Phillip Bell. "Froome's values are close to what we believe are the upper limits for VO2 peak in humans.''
The lab also found that Froome can produce up to 525 watts of power when he pedals, and can also sustain a very high power output - 419 watts - for 20-40 minutes. Such numbers could help explain why Froome not only looks comfortable on the Tour's steep and long mountain climbs, but can also squeeze out bursts of speed when necessary.
''I'm the only one who can really say 100 percent that I'm clean,'' the magazine quoted Froome as saying. ''I haven't broken the rules. I haven't cheated. I haven't taken any secret substance that isn't known of yet. I know my results will stand the test of time, that 10, 15 years down the line people won't say, `Ah, so that was his secret.' There isn't a secret.''
With skepticism rife in cycling after Lance Armstrong was stripped of his seven Tour wins for systematic doping, the tests on Froome are unlikely to assuage die-hard doubters. But in submitting himself for tests and releasing such personal data, the Sky rider is going the extra mile to be more transparent than many other top athletes, who generally don't publish such information if they have it.
The 2013 and 2015 Tour winner has never failed a doping test but got a rough ride from some race commentators and a tiny minority of roadside spectators on his way to victory in July. He said one man even splashed him with urine.
''It's hard not to get angry. You think, hold on, what people are actually accusing me of is so severe - it's basically calling me a complete fraud,'' he told Esquire.
''All the hard work, all the training, goes out of the window when someone says you're doping. It does bother me. But at the same time I can understand where the questions are coming from. Questions do need to be asked. As long as the questions are fair, I'm happy to answer them.''
One of the most vocal and persistent skeptics of Froome's performances is Antoine Vayer, who worked as a trainer for the Festina team caught in a doping scandal at the 1998 Tour. Vayer wasn't impressed by Froome's test results.
''It doesn't change anything,'' Vayer said in a phone interview. ''None of these tests show he's an exceptional athlete. It's an effort to calm things down and not reply to the difficult questions. For me, it's not reassuring.''