What Chris Froome needs to do to address doubts: cycling analysts weigh in

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As the countdown to the release of Chris Froome’s data continues, two of those who have long tracked climbing data and other performance parameters in cycling have given their thoughts on what they believe is warranted.

In this post we laid out the reasons why the long-running calls for Froome to release extensive performance data are justified.

Now, sport scientist Ross Tucker and US sports medicine physician Mike Puchowicz have detailed exactly what they believe Froome should do in order to assuage questions about his performances.

Froome made a sizeable jump in performance in 2011 while trying to retain his place on Team Sky. His contract was not set for renewal but, after he started that year’s Vuelta a España as a domestique for Bradley Wiggins, he quickly showed that he was in condition to aim for overall victory.

He grew stronger as the race progressed and finished just 13 seconds behind Juan José Cobo at the finish in Madrid. Had he not waited for Wiggins on key mountain stages, he almost certainly would have won.

At the time Froome explained that the improvement in his form was due to the discovery and successful treatment of the disease bilharzia.

He then finished second to Wiggins in the 2012 Tour, and went on to win the 2013 and 2015 editions of that race.

For both Puchowicz and Tucker, it is essential that any data released helps explain how Froome turned his career around to reach the point where he is the dominant Grand Tour rider of this generation.

“Froome is in a tough position because the conversation has shifted to this nebulous debate over transparency, and away from focused question that are potentially answerable,” said Puchowicz, a sports medicine physician for the Arizona State University Health Services and author of the Veloclinic blog.

If things were taken back to those relevant questions, he said that he has a clear idea as to what they should be.

“Number one is whether he always had the performance potential despite any real notable performances prior to the 2011 Vuelta,” he explained to CyclingTips.

“According to [Team Sky Principal Dave] Brailsford, he did. He said that, ‘what has quizzed us has perhaps been his under-performance prior to this, rather than the over-performance here in Spain. Physically Chris Froome is very gifted and we’ve always known that the power-to-weight ratio he produces is phenomenal.’

“This assertion could be backed up with power data from training prior to 2011, showing performances that would have put him in GC contention had they come in a race.

“Similarly, VO2 and metabolic threshold data before and after 2011 would also help demonstrate that the phenomenal physiology was always there, as Brailsford claims. Post-transformation data alone is not helpful.”

Tucker argues the same point, saying that simply showing his physical capacities in 2015 will do nothing to earn trust.

“It needs to be longitudinal data, more than anything,” he told CyclingTips. “The question around Froome, perhaps the main one driving this research, is to provide some sort of ‘validity’ to his performances. That’s not going to come from a single test, not even close.

“To use an analogy I’ve leaned on before, it is one pixel in a very large picture. There are some circumstances where the data from a single test would be revealing, which I’ll get to, but generally, the most important thing is longitudinal tracking.”

What results will likely be published from 2015 lab test?

Putting that long-term data to one side for a moment, Tucker explains the figures he expects from the post-Tour lab test, as carried out at the GlaxoSmithKline Human Performance Lab.

He believes the testing will include a measure of Froome’s VO2max, which he defines as an indication of the size of the engine plus his efficiency [an indication of his ability to use oxygen to produce energy without waste]. Together these are crucial to sustainable power.

He also said that a lactate threshold indicator is important, as it measures a rider’s ability to ride at a high sustained power output for prolonged periods.

“What will they find? VO2max will be above 85ml/kg/min, I’d guess 88,” he predicts. “Efficiency will be 23% to 24%.

“That combination of physiology would be very rare, but not implausible. It’s also what you would predict for a cyclist who can sustain 6.2 W/kg for 30 minutes, or 6W/kg for 45, which we already know Froome can do. This is why I’m saying all we are going to get is clarification of the inputs.”

“Again though, what it doesn’t tell us is how that physiology came to be.”

Chris Froome (GBR/SKY)Post-Tour Criterium Mechelen 2015

Looking under the hood

Tucker, who has many years of experience in sport and who is behind the compelling Science of Sport site, points out that many have called on Froome to ‘do a test (singular) to prove you are believable.’ He makes clear that it is an unfair request as no single test can do that.

He explains why. “What we’re going to get is our first look “under the hood” of a Tour de France champion at his peak. And that’s cool, make no mistake, and good on him for doing that,” he said.

“But if that sneak peek under the hood is offered as a reason for trust, then we’re being manipulated. Why? Because it’s like clocking a car going 340 km/hr, and then looking under the hood, examining the specs.

“You know what you’re going to find – a certain engine, certain fuel use, certain aerodynamics. Those are the inputs that have to be associated with the outputs.”

As Tucker points out, those outputs are already known. They are, more or less, six watts per kilo for 30 minutes or more, and other such figures. But that’s not what is really needed.

The problem with any single lab test is that any rider using doping products will, by the nature of those substances, experience a boost in performance. That would enhance the test, and this in turn mean that looking at a singular set of results proves little in terms of showing a rider is clean.

“The real story is how those inputs were created,” he continues. “And that requires a little more than a once-off test. As I say, it’s harsh on Froome to say that, because he will (partly correctly) point out how he’s done what was asked, but that’s not entirely true.

“Some asked for once-off testing, but they assume that once-off testing proves that he’s clean or not. It can’t. Longitudinal is the way forward.”

Froome has indicated that he will also release details from a 2007 VO2 max test carried out at the World Cycling Centre, but it is unclear what other physiological data will be published.

Explaining a transformation

Like Puchowicz, Tucker said that it is his transition from his early years to the Vuelta 2011 breakthrough and beyond that is needed.

“Taking a snapshot of him in September 2015 will offer little in the way of understanding the journey that took a mid (at best) of the pack rider from a grupetto to the front of so many races, in dominant fashion.

“We need to see the movie, not the still snapshot. That’s why I, and many others, have called for performance testing to be part of a biological profile concept, not this once-off thing.”


If he was designing the protocol for Froome’s data release, he said that a clearer picture of the Briton’s evolution into a world-beater would include both longitudinal testing and longitudinal biology.

“He’s already in a mess because of this timely bilharzia diagnosis, and the asthma, and that was compounded by the transformation in the total absence of physiological data from his pre-champion days,” he said.

“He went from a donkey to a racehorse with nothing but a medical diagnosis for it, and then added asthma. Now he will provide the physiology of a race-horse, but it won’t win over anyone who doubts.

“What might help – but it’ll never completely change it, such is the scepticism – is to link longitudinal physiology to longitudinal biology. And to be more transparent.”

Puchowicz echoes this. “If the physiology did change as the performance suggests, is there a legitimate reason that allowed the transformation?” he asked.

“For example, if he had chronic anaemia due to a parasite, documentation of a change in his blood profile with a correction after treatment could support this claim.

“If the transformation was due to weight loss, this data could be provided.”

In other words, both would like to see data showing how he went from a rider with occasional flourishes of good performances to one who very nearly won the 2011 Vuelta, and then finished second, first, and first in the 2012, 2013 and 2015 Tours.

If that was provided, both would feel a solid level of transparency would have been shown.

Final thoughts

Tucker makes an interesting point in terms of the process. He outlines what he describes as something that could have been ‘a huge strategic opportunity’ for Sky, but one that wasn’t availed of.

It involves French coach Antoine Vayer and Irish journalist Paul Kimmage, two who have frequently questioned Froome’s performances.

“There’s one big thing the team missed,” Tucker explained. “They should have invited Vayer and Kimmage to be there [at the testing] too. Those are the biggest detractors, and they do have some influence.

“They would have lost nothing from that invitation, because if Vayer is invited and doesn’t go, he basically delegitimises his own criticisms of Froome. From that day onwards Sky could say that Vayer is simply on a witch-hunt and didn’t even show an interest when they invited him in.

“Alternatively, if Vayer agreed to go, watches the testing, he’s linked to physiology that will not clear Froome, but also won’t convict him.

“As I said, this single snapshot is not going to sway the argument either way, but having Vayer in the room, part of the testing, would have been a show of maximum transparency. It would win a lot of trust from marginal onlookers.

“The same can be said of Kimmage – get him in there. Your biggest detractors or disbelievers are going to be your biggest allies, if you can win them over.”

Because neither were there, he believes an error was made. “They didn’t do that, and so they’ll be accused of manipulating the process, as is usual for Sky. Opportunity lost.”

Puchowicz said that if he was to give advice to Froome, it would be one thing in particular. “Only make claims that are fully plausible and supported by strong evidence.

“Evidence that is not strong enough to offset the overwhelming evidence of doping and cover-up at the highest levels of sport [in general, not specific to any one athlete – ed.] is unlikely to tip probability or sceptical opinion in his favour.”

As for Tucker, he concludes his thoughts by saying that he hopes that other riders will follow suit.

“I’ve said for a few years that I think regular performance testing would be a good thing for anti-doping. Obviously I’m biased in saying it would be really fascinating.

“I think many people who follow cycling do have the capacity to understand this kind of process and the data, and so it would be good for the sport in general.”

“But,” he added, “it would have to be done in a controlled way, and I have my doubts over whether that would happen.”

Time will tell if other top riders will be transparent. For now, just as Froome has led the way in the 2013 and 2015 Tours, he has a chance to do so again when his data appears later this week.

That’s to be applauded, but will the data be enough? We’ll find out very soon.

Also see: Opinion: Why Chris Froome’s data release is warranted, overdue and potentially a big step forward

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