Debate after Sky releases Froome’s data; Tucker argues numbers don’t add up
GAP, France (CT) – Team Sky responded to calls for it to be more transparent on Tuesday’s second rest day of the Tour de France yet, for some, the release of climbing data from Chris Froome ended up creating as many questions as it sought to answer.
The team said in the lead-up to the heavily-attended conference that it would consider putting some figures into the public domain. Speaking in the course of that conference team principal Dave Brailsford confirmed this was the case, and said that the recent Stade 2 programme on the France 2 channel had been the main catalyst.
Brailsford had appeared on the programme but said that he felt ambushed when he was grilled on a number of factors, including the testing of Sky riders on Tenerife.
He also faulted the conclusions drawn by French physiologist Pierre Sallet, who he said had claimed Froome hit a power output of 7.02 watts per kilogram on the final climb on stage 10 and who had raised suspicion about the data. [Note: Others said that Sallet’s figure related to MAP, or Maximum Aerobic Power, rather than average power]
“Of course it did take me a bit by surprise. And that was very obvious, really,” said Brailsford on Tuesday. “And I did feel a little bit uneasy, I must admit, when I was getting asked about why you go to Tenerife? Why haven’t you been tested in Tenerife? When, in reality, we have been tested 25 times this year there.”
The team’s performances came under the spotlight in the 2012 and 2013 Tours when it was the dominant squad and won the race via Bradley Wiggins and Chris Froome.
Brailsford saw those questions as being part of the inevitable fallout from the Lance Armstrong/US Postal team investigation, saying that any winner of the race was likely to be under the microscope.
Those questions reared up again this year when, on stage 10 of the Tour, Froome dominated to ride away from all of his rivals and team-mates Richie Porte and Geraint Thomas raced in to take second and sixth.
The demand for transparency then intensified when data emerged of Froome’s display on Mont Ventoux in 2013, with the superimposing of power, cadence, heart rate and speed figures on a video of the stage showing his win in clear detail.
The team claimed at the time it had been hacked, but then refused to further comment on the matter to the media.
Froome insisted repeatedly that he was a clean rider and had nothing to hide, but some of the French public were sceptical and were vocal about it. One even threw urine in his face, an action that was universally – and rightfully – condemned.
These aspects all contributed to the pressure on Sky to release data, but Brailsford said the French television programme was the biggest factor.
“I just think in particular what France 2 did, putting out that big headline, 7 watts per kilo, a picture of Lance Armstrong and a picture of Ullrich…that was so wildly wrong on so many levels that we thought that actually we should correct that,” he said.
“[We felt we should] give the concrete fact and give the evidence so that people can judge for themselves why would you do that. That was really what drove my decision on that one.”
“I do think that in this day and age in the sport of cycling people do have to be responsible. I think in terms of if you are going to present something on television to a nation, then you do have an obligation to get your facts right. So it is a bit disappointing.”
Confusion over figures released
Four people from the team were centre stage at the press conference; Froome, Thomas, Brailsford and Tim Kerrison, the team’s Head of Athlete Performance.
The latter explained that there was some reluctance to give too much information away publicly as he believed it could cost the team some of its competitive advantage. However, he said that the team had given over a billion data points of data to UK Anti Doping at the end of 2013 and had continued to collect data since.
“As was said in the past, we are more than happy to share all of that data with the relevant authorities who are responsible for overseeing the sport,” he said.
As regards this year’s Tour, he said that the team had decided to share data from that first big mountain stage, the summit finish to La Pierre Saint Martin.
He said that the numbers pertained to a 15.3 kilometre section, which he took as the starting point, and which was covered in 41 and a half minutes. That equated to a VAM (climbing speed) of 1602 and a recorded average power of 414 Watts.
However, he said that Froome’s use of Osymetric (non-round) chainrings caused his Stages power meter to overestimate power by six percent.
“That has to be considered when interpreting Chris’ power,” he cautioned. “But with his weight hovering around 67.5 kilos, that gives us a corrected power to weight of the whole climb of 5.78 Watts per kilo.”
It is this latter figure which has provoked so much debate. Ross Tucker, a South African sports scientist, has been one of those who has been most vocal in recent years about the team’s need for transparency. He, along with others, has been calculating and analysing climbing data on his Science of Sport website.
Brailsford has been dismissive of the practice, referring to it as pseudoscience, but the leaking of Froome’s Ventoux data showed, for that climb at least, that the calculated figures were almost exactly correct.
CyclingTips spoke at length to Tucker after Sky’s release of data. He said that he was sceptical about the figures.
The reason for his doubt is that other riders such as Robert Gesink and Laurens Ten Dam (both LottoNL-Jumbo) have published their power figures online and that these jarred with Sky’s data.
Gesink finished fourth on the stage, one minute and 33 seconds back, while Ten Dam was 22nd, four minutes 25 seconds behind.
He believes Froome’s numbers simply don’t sync with the other three.
“You have Froome at 5.78 watts per kilo, gaining one and a half minutes at a guy who is at 5.9 [Gesink] and four and a half minutes on a guy who is 5.5 [Ten Dam].
“So whether the gaps are to people who have got a higher power output or lower, you cannot make those numbers fit. How can a car travelling 60 miles per hour go faster than a car travelling 70? It is ridiculous,” he said.
“It is going to sound ludicrous for me to say, but it is impossible to ride at that speed at such a low power output. It is just not possible. Because it means the rest of the Tour de France then is going five percent slower than we have ever seen, yet their times are the same.
“That is why I facetiously said earlier [on Twitter] that I woke up in a parallel universe where everything must be a tailwind. You cannot ride that speed at that power output.”
“Instead of clearing anything up, it is just muddying it even more”
So, how to make sense of the numbers? Tucker states that the more riders’ numbers are released, the more certainty there can be about what a climb requires.
“You can’t expect Sky to release the data for Contador and Nibali and everyone else, but they did have access to other people’s data,” he said, referring to Porte, Thomas and the other Sky riders.
“If that had been me, if I had been sitting in Tim Kerrison’s seat, I would have made sure that I shore up my argument with all these supporting lines. It is just basic science.”
So, if we consider his argument that the average watts cited by Kerrison is implausible, how does he believe Sky arrived at the figure it quoted?
“I think there are two ways that you can justify it and a combination of the two for me explains it.”
He believes there are two sources of potential error which explain how Froome can apparently ride at a lower watts per kilo output than Gesink yet finish one minute 33 seconds quicker.
The first of those relates to the overestimation of power due to the Osymetric chainrings when measured by the Stages system.
“The manufacturer claims four percent,” Tucker said. “But Tim Kerrison reduces the measured power output by six. I think if they reduced it by four percent, then the power output they would have got would have been higher. Not a lot higher, but enough.
“414 Watts is what is produced on the reading. So if you knock 414 down by six percent you get 389. What they have then done is they have divided that by a mass of 67.5 and they get 5.77.
“But if you put in that 414 and brought it down by four percent, then what you get is 397. That translates to 5.89 watts per kilo on that same mass.”
According to The Telegraph, Froome’s weight prior to the Criterium du Dauphiné was 66 kilos. Riders generally lose weight between that preparation race and the Tour, yet in a press conference in Gap at the end of stage 16, Froome said that he was racing between 67 and 68 kilos at this point of the Tour.
Tucker states that if that pre-Dauphine weight is used instead of the claimed Tour weight, things start to make more sense. “If you had a combination of a four percent reduction [accounting for the Osymetric/States error] and a mass of 66, then you have 6.02 watts per kilo. Now I think it starts to add up.
“The picture they are trying to portray is one of low power output because it has low physiological implications,” he said. “Instead of clearing anything up, it is just muddying it even more.”
Asked how things could be more definitive, he points to a couple of elements.
“Well, you need the true weight, but then what would help is if you had other data as well. This is a classic example of going not far enough, providing only enough data to pacify what seems like a lot of people but which actually creates greater confusion.
“You have got Geraint Thomas and Richie Porte on the same climb. Sky could provide their data to validate Froome’s, but they didn’t. Why did they not do that? It makes much more sense to have done so.”
“I am afraid this is not transparency, in my opinion”
Tucker states that the figure of 6.02 watts per kilo doesn’t by itself prove doping, but he does have reservations about the bigger picture. By this he means the sum total of the performances by Froome since his career turnaround at the 2011 Vuelta a España, and also what he says is Sky’s lack of transparency since then.
He said he is also troubled by other issues such as the team’s past employment of Geert Leinders, a doctor who has since been handed a lifetime ban by US Anti-Doping Agency (USADA), Anti-Doping Denmark (ADD), and Anti-Doping Authority Netherlands (Dopingautoriteit) for doping riders on the Rabobank team.
Team Sky insists that was unaware of his past when it brought him on board and maintains that he didn’t do anything unethical while with the team.
Tucker appeals for complete transparency from the squad, arguing that the selective and limited release of data on Tuesday did nothing to improve things.
“I’m sceptical because it just seems both inconceivable and incomplete. It’s inconceivable in the sense that I woke up this morning to a world where you can climb at a low power output and go two minutes faster than a guy who is climbing high powered.
“It’s like a world where a car travelling at 60 is faster than a car travelling at 70.
“And it’s incomplete as there are ways to account for that discrepancy and mismatch because you have got data, you have got data from your own guys, but for reason you are still holding onto it.
“l know some people will now say ‘you can never be satisfied because you have asked for transparency and they have given it.’ But I am afraid this is not transparency, in my opinion.”
It remains to be seen if the squad will issue any more information in the weeks ahead. Speaking Tuesday, Brailsford called on the UCI to collect data from all the teams and to monitor this.
He said that Sky faced greater demands for transparency than other squads do, asking if it was fair.
That said, he accepted that Sky’s success in the Tour heightened the demand for data.
“I think we face greater questioning maybe than other teams. I think that would be fair [to say],” he stated. “I think most people who watch it would say that is the case.
“And whether we bring that on ourselves or not I don’t know, but we are quite happy to answer them and we are going to continue to work in the way that we work.”
He said that the immediate priority was to focus on the rest of the race and bringing yellow to Paris
“We are quite willing to take a step, but we are not going to get caught in an endless debate,” he continued. “We are going to carry on racing and then we will address it after the end of the Tour if necessary.”