The Tour de France: midway science overview

Ok, so it's not entirely mid-way, but I thought that with the current 'lull' in proceedings between the Alps, which ended yesterday, and the first individual time-trial and Pyrenees coming up on the weekend, it would be a good chance to cast a 'physiological' eye over the race and give some impressions.

It's been a frantic few days of racing. It's quite evident that we are watching one of the most wide-open Tours in recent times. The same was said about last year's race, but this is something else. On Saturday, Sunday and yesterday, all the Alps stages, at least four or five different riders all launched multiple attacks - gone are the days of one definitive attack from an Armstrong or Pantani and the group was split - this is real racing. It's interesting to speculate on the physiological basis for this. A big factor is the absence of a strong, dominant team, riding hard tempo to the bottom of the climbs. In the past, this has allowed Armstrong to put his opponents into difficulty before even launching the attack - 'softening them up', so to speak. This year, perhaps the absence of that hard pace leading into the climbs has allowed a lot more riders into the contest. The result is that a rider who attacks, with a surge of say 700W for 45 seconds, is not able to do quite enough to drop riders who bridge gaps a little too quickly. And then once they are all together, the stronger riders are not quite able to overcome the benefit of drafting for riders behind.

The only exception was Rasmussen, but he was allowed to go by the peloton, and it will be interesting to see whether his attacks are able to split the group once we are in the Pyrenees. But at the moment, the attacks are threatening, but never quite cracking riders. This means that perhaps all the riders are within 5% of one another in terms of power output, and so the small difference made by wind resistance on the climbs is enough to keep weaker riders in a group, or conversely, to prevent stronger ones from quite escaping.

Rasmussen's effort the other day was special - he rode a solo mountain ride and then recovered enough to mark attacks over the Galibier, which in my opinion was an even better ride. It will be great to see if he does this in the Pyrenees. Unfortunately for him, his time-trial ability may undermine his efforts. This of course means he will have to attack in the Pyrenees and then we'll see whether he's the best man this year.

The other fascinating thing is to observe whether all the "infighting" that has gone on between the likes of Contador, Mayo, Valverde, Moreau and Evans comes back to haunt them. They have expended a lot of energy without much reward over one another. One sure thing is cycling, as in physiology, is that there is always "a bill to pay". And the attacking that was going on during the climb up to Tignes and on the Galibier will certainly have a cost.

And the silent followers - Saster, Leipheimer and Kloden - who have been sitting in and bridging gaps more gradually, may benefit in the third week. Physiologically, the effort that it takes to accelerate and attack is enormous - it places a real demand on the sympathetic nervous system and this stress response is ultimately what hinders the cyclist as the Tour goes on. It's all about what in science is called the HPA axis - hypothalamic Pituitary Adrenal axis (we'll stick with HPA then!). So these guys, who attacked one another relentlessly may well pay for it on the Plateau de Beille, or possibly even during the TT the day before. And the guys who've been steady and consistent are likely to be stronger in week 3, and that makes for interesting racing!

So that's our halfway assessment of the Tour. In the coming days, we'll have a more in-depth look at the physiology of the Tour, including a look at how much energy these guys go through and what they have to eat. We'll also do post that explains just what sort of power outputs they need to be competitive and also what happens to their bodies during the race.

Until then, enjoy the clash in the Pyrenees!

R & J