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Sunday, July 22, 2007

Vino's back - a dominant time-trial explained

So yesterday, Alexander Vinokourov, featured in the photograph above as being in tears after a dreadful two days in the Alps, where he lost close to 5 minutes on the race contenders after an accident, revived his chances and moved up to 9th in the GC. He's still 5.10 back of Rasmussen, but only 4 minutes behind the other big contenders, and assuming Rasmussen can't steal any more time in the Pyrenees, they are more likely to be threats. So it all makes for a fascinating excursion into the Pyrenees.

But we need to get some insight into the science and physiology that might explain how the Kazhak rider managed to comprehensively destroy the best time-triallists in the world, having been so humbled a few days earlier. Vinokourov is a strong time-triallist, sure, but he's not the dominant TT rider in the field. He probably wouldn't even have been the best TT guy in his team! Yet yesterday, he put more than a minute on everyone, doing the sort of ride Indurain and Armstrong used to do.

So obviously, those injuries and sicknesses are a thing of the past. But a factor that I believe is critical is that Vino has actually had a pretty easy couple of days in the Alps, absolutely speaking. Before everyone protests that he's suffered more than anyone, there is a theory in exercise physiology that says that the brain is controlling exercise performance, adjusting the level of muscle recruitment to determine how fast or slow the athlete goes. It does this by taking into account ALL the physiological systems and their inputs. In othewords, the brain is asking things like:

How much energy do I have available? How hot am I now? How hot am I likely to get? How much oxygen do I have available? etc.

And it's in response to these questions that it allows riders to speed up, hold the pace, or forces them to slow down. For example, if the rider is not losing heat fast enough, the brain detects a rise in heat storage, which could potentially cause body temperature to rise, and once the body temperature reaches about 40 to 41 Deg, well, that's lights out time! So the brain down-regulates the amount of muscle that the rider can use, and less muscle activity equals less heat production. Unfortunately, it also means going slower, but that's the compromise that allows the rider to finish without over-heating (called hyperthermia).

So what does this have to do with Vino? Well, my opinion is that in the Alps, his brain was simply not allowing him to push into "the red", because the sensation of pain and weakness in that knee and the whole body systemic problems after his crash were limiting the brain from doing this. So even though he suffered and had two terrible days in the Alps, his absolute riding intensity was pretty low, certainly by comparision to those ahead of him, especially Valverde, who were attacking like men possessed on the climb to Tignes and the Galibier. When we talk of "absolute", we mean that his efforts were not maximal for what he is capable of - he did suffer, sure, and relatively, he felt like all the other guys, if not worse. But he simply didn't pump out the same wattages, or place the same demand on his physiology, because his brain didn't allow it.

The net result of all this is that even though Vino had a bad time, he actually was spared the physiological damage of riding at 90% - his brain kept him at 80%. That 10% is the difference in the TT.

So moving forward, Vino probably has a good day or two left. But don't expect him to dominate the final TT next weekend, because by then, he'll have had a few days of really hard racing, in absolute terms, and that means he'll start the TT in the same kind of shape as the others. Whether he'll be in yellow then, time will tell...

As for today, Rasmussen is highly unlikely to be able to attack, because yesterday, he gave it everything to stay in the Yellow Jersey, and that effort will blunt his ability on the Plateau de Beille! And expect Valverde to attack wildly, but for Kloden and Evans to be the big threats to Vino, who I think will probably edge out a sprint at the top!


See also:

Vino and Kloden - the physiology of a bike accident

The Tour de France: midway science overview

Midway analysis of the Tour continued: Vino's chances