Sky releases Chris Froome’s powermeter data from stage 10 of the Tour de France

by CyclingTips


At the Tour de France’s second race day in Gap Team Sky released power data from race leader Chris Froome’s stage 10 ride in the hopes to silence critics of his performance.

Speaking to the press, Team Sky general manager Dave Brailsford said: “We thought we’d give people concrete numbers and facts. We’re not going to get caught up in endless debate. We’ll give you info, carry on racing and then address it after the Tour if necessary.”

Head of Athlete Performance Tim Kerrison said: “We have a lot of data on our riders and the way we apply and use it, we see that gives us a competitive advantage. As in most industries, knowledge and intelligence is giving a competitive advantage.

Tim Kerrison has also spoken about human limits. He told AFP, “For sure there’s a limit to human capabilities, although I’m not sure what the process would be to define that line.”

“Human performances evolve and we’ll all be sitting here in 30 years thinking [Froome’s latest performance] wasn’t that remarkable.”

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“It’s difficult to indicate the exact start of the climb, so I’ve analysed the last 15.3km, which is an effort of about 41 and a half minutes.”

Below is the data that was sent out to media attending the press conference:

Stats of final 15.3km of the final climb on stage 10:

Time: 41:28
Average power: 414w
VAM: 1602
Chris’s weight: 67.5kg
Corrected power/weight for the whole climb: 5.78w/kg

Team Sky claims that when used in conjunction with osymetric chainrings, power meters over-report power by approximately 6%. We have not been able to verify this. The above figure of 5.78 w/kg is corrected to take this into account. Without making this correction, the power/weight would be 6.13w/kg. All other power values stated here are the actual reported power values – i.e. not corrected.

(Team Sky claims that to go from this value to estimates of physiology (e.g. VO2max) requires assumptions about relative aerobic and anaerobic contribution, sustainable percentage of VO2max for the duration of the climb, and efficiency and economy of the rider and there is margin for compounding error in making these such assumptions.)

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Gearing:? 52-38 / 11-28
Average Cadence:? 97rpm
Average HR: 158
Maximum HR: 174

Kerrison said that this is a very high heart rate for Chris suggesting that he has reached the second week of the Tour/bottom of the climb in a relatively fresh state. By comparison, Chris’s maximum HR in the second week of the Tour in 2013 was 168. In the Vuelta 2014, it was 171.

Froome’s stage 10 attack data:

Duration: 24s
Average Power: 556w
Peak power: 929w
10s power: 652w
Average Cadence: 102rpm
Average Speed: 25.3kph
Maximum Speed: 27.7kph
Power for the 4 minutes before the attack: 449w (18.2kph, 1777VAM, 9.8% gradient, 94 rpm)
Power for the 4 minutes after the attack: 435w (20.4kph, 1718VAM, 8.4% gradient, 103 rpm)

After the initial attack, when Chris continued to ride away from the field, his power and climbing speed (VAM) were lower than before the attack.

Froome said that he would not let the bad publicity affect his performances.

“All that has been going on in the sidelines really has been more of a sideshow, my focus has been on the race and I think the racing shows that nothing’s thrown me off in that regard,” Froome said.

I’m not sure if numbers are going to fix everything, but certainly I feel as a team and myself, we’re definitely trying to be as open and transparent as possible”

via Team Sky press release

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