What has Froome made public?
From what I’ve seen, we’ve got headline data on a variety of tests which measure VO2 max, or oxygen uptake per kilo of body weight, sustained power output, as well as the comparison with the testing he did in 2007. I haven’t seen the detail of the protocols but I know the people at GSK and I’m sure they have done them well. Froome has been bold and open. I’m not sure what question he is answering, though. These are standard data that you would expect to see in a champion cyclist and you can’t read more or less into it than that.
What does the data tell us?
We have a VO2 max figure, a value that some people consider to be a determinant of endurance performance. It’s a high value, close to 90ml/kg, which is extremely high. I don’t think many higher have been recorded. It’s impressive but not outlandish. It’s what you would expect of a Tour de France winner. We know he has managed his weight very well, but whether he is different from the competition in terms of being lean and light I don’t know. The sustained power figure looks reasonable if you look at the figures Chris Boardman and others have done for the hour record.
What else should he tell us?
Efficiency is the one thing that we don’t know much about. I suspect they have measured it but perhaps it is too difficult to convey in the article. I imagine we will see it in the scientific paper when it appears. Some people are more efficient than others and even a small advantage could be important. You can’t interpret the VO2 max figure in isolation, without knowing what his efficiency values are.
How could you measure efficiency and why does it matter?
I don’t know how much work has been done on how much energy he expends, but it would be very surprising if they hadn’t measured it in the lab. It’s measured in how much oxygen you need to use for a given power output or over a given distance. You could have two individuals with a VO2 max figure of 70, but if one is more efficient he will travel faster for a given oxygen uptake. There may be others with similar VO2 max figures in the Tour but Froome may be more efficient.
What dictates efficiency?
Biomechanics, physical dimensions, technique, body composition, aerodynamics, to cite some examples. It has been suggested, for example, that individuals with a higher proportion of slow-twitch muscle fibres may be more efficient.
Is there any more information that Froome could give us?
I don’t think so. I don’t think this was ever likely to convince the doubters, although personally I’m not in any doubt. I’m not really sure what people wanted or expected to see. He has released physical data which shows values akin to what you would expect, but in any case the data would be unlikely to tell you if he had doped. He was asked for the data and he has put it out there.
Dr Andrew Jones is professor of applied physiology at the University of Exeter
