453 Watts for the final 2km: A look at Stage 4
Just a very short post as a follow up to the earlier post on the power output during the Tour de France. And for this, credit to SRM, whose website is an absolute must for anyone really interested in crunching the numbers on the Tour. The truth is, they do such a great job of breaking down the power files of their riders that it sometimes feels unnecessary to do it again myself, but there are some insights I'd like to try share regarding what happened on the climb up to the Mur-de-Bretagne.
So again we look at Chris Horner - 10th last year, a podium contender this year, he's going to continue to be a great barometer for what is going on at the very front end of the race.
Below is his power output file for the entire 172km (again, click to enlarge).
It shows some of the features we mentioned in our post earlier today - a relatively low average power output of 216 W (still significantly higher than the 176W of stage 1), but particularly in the flatter sections of what was a "bumpy" stage. For long sections, the power output is below 180 W (the green line in the above graph), but that is also dictated by the profile of the stage - the black line is the altitude graph and if you look at that, combined with the pink trace showing speed, you get an idea that yesterday was a pretty up and down stage, fast then slow, high intensity over rolling terrain. These types of days are often more taxing than longer, but steadier mountain stages. In fact, at first glance, the power output profile resembles an interval-type session.
But the real story is the final 15% of the stage, and in particular, the last 2km, where the race broke up and Alberto Contador attacked. Horner's average power output for the final 25 km (which took only 31 minutes) was 318 W (5W/kg), building progressively towards the finishing climb, where it really ramps up.
The Contador attack actually created a small gap over Horner, who ended up 8 seconds down on the stage, but his power output file for those final 2km reveal just how intense the effort was at the front of the race.