Froome’s argument, as far as I can tell, hinges on a claim that a) peak urinary salbutamol levels occur within one hour of inhaling the substance (Heuberger’s theoretical model); and b) he inhaled the maximally allowed amount of 800 ug within one hour of the finish on stage 18, where he tested positive. With regard to a), the model estimates that roughly 7-8% of the time that 800 ug is inhaled (my estimate from the figures Heuberger actually published) within one hour of providing a sample, the concentration in the urine will exceed the 1430 ng/ml value that is Froome’s 2000 ng/ml, corrected for a urine specific gravity of 1.028. I’ve already pointed out that the studies that look at salbutamol concentrations at this time don’t support this, but let’s ignore this for the moment, to follow the rest of the argument.
With regard to b), Froome has claimed he took 2-3 puffs after the stage was over. He would further have to argue that he took 5-6 puffs within an hour of the end of the stage. If you look at the stage, it wasn’t considered that difficult. There was a steep climb at the finish, but it was fairly short, not a typical long climb that might result in large time gaps between contenders. In fact, an hour from the finish, Froome was almost to the top of a preceding climb, and after that, there was a long descent, followed by a gradual climb, and finally the short, steep climb at the end. So it would not appear to be the kind of stage that would require an unusual amount of salbutamol, given that he has said he only takes it during “great efforts”. He did imply, of course, that he suffered an unusually severe attack that day, but even if we accept this, it doesn’t suggest that he would have taken 5-6 puffs in the final hour, as opposed, e.g., to taking some of it earlier in the race.
But let’s assume he did. Now I pointed out that there are several studies indicating that inhaling 800 ug, followed by providing a sample one hour later, does not in fact result in the high levels claimed by Heuberger, et al. But Froome himself might be used to test this notion. If he generally takes salbutamol only during “great efforts”, one would expect his highest urinary salbutamol levels would come following mountain top finishes. Not only would they require the greatest efforts, but since they come at the end of the stage, they would soon be followed by providing a sample. The inhaled drug would be at peak concentration, and because the finish is so close, he presumably wouldn’t be urinating, which would reduce the concentration in a subsequent sample.
How many such finishes has Froome recorded? Looking just at the six GTs that he has won, I counted 32 mountain top finishes which he either won and/or completed while in the leader’s jersey, which would ensure he would be tested. I would think that in many if not all of those finishes, he would take a substantial amount of salbutamol within an hour or two of being tested. If the variation is as great as Heuberger claims, some of those samples ought to have pretty high salbutamol levels. Maybe Froome never took 800 ug before, but the model is certainly capable of predicting the pattern of variation expected from a fewer amount of puffs. But it doesn’t appear that the variation was that great. Not only has Froome never exceeded the decision limit for salbutamol before—unless he somehow was able to convince UCI that there was an innocent explanation—but IIRC, it was reported that none of his other Vuelta samples exceeded 600 ng/ml.
So though I would have to see more data, I’m guessing that Froome’s own samples are not going to support the model very well. If they don’t, then along with the published studies—not to mention the theoretical problems with Heuberger’s study—I don’t see how the argument will succeed. An argument based on large variation has to show more than one outlier.
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