Monday, July 18, 2011

Voeckler on Plateau de Beille: 2004 and 2011

A lot has been said and written about Voeckler's remarkable climb to Plateau de Beille in stage 14 of this year's Tour. Voeckler had an advantage of 1:49 over second-place Fränk Schleck, 2:06 over Cadel Evans, and 2:18 over Fränk's brother and teammate Andy Schleck. Due to time and fitness lost in a crash, race favorite Alberto Contador was 4 minutes down. Any of these riders were considered a threat to overtake Voeckler, although the consensus most likely scenario was Voeckler would limit his time losses and hold onto the yellow jersey by maybe 30 seconds.

Strava KOM: around a half-hour slower than Voeckler's time.

Yet it's safe to say it was a shock to almost everyone when Voeckler not only held on to his lead over all other contendors for the yellow, but was a primary activist in chasing down attacks. I'd have expected Voeckler, by any reasonable measure outmatched in that group, to take a very conservative approach to the climb, following the smoothest wheel to avoid going into the red for even a few seconds. Cadel Evans and Alberto Contador are both exceptional in their ability to put on short bursts of amazing climbing speed. So if Andy Schleck attacked, Voeckler could have let one of these riders close the gap, perhaps following Basso who would steadily bring it back together afterwards. But instead Voeckler was sprinting back to Andy's wheel himself.

Voeckler's special motivation on the climb.

Meanwhile, Andy was tempering his attacks based on what was evident weakness in his brother. Fränk obviously wasn't feeling as frisky, and the risk was an attack by Andy could result in nothing more than Fränk getting dropped from the group. That would hardly serve his team's interest. Of course, best of all would be for Andy to attack and get away solo, something a lot of his fans obviously wanted to see, but Andy had a good view of how his brother and the others appeared, and if Fränk was a weak link, he may have realized the team would do better by staying united at least until the upcoming Alpine climbs.

All of this start-and-stop worked to Voeckler's favor. Voeckler is also a punchy rider with a strong top-end, but where he'd have most likely succumbed would have been a faster, steady pace. The lack of cooperation among the favorites also allowed first Jelle Vanendert and later Samuel Sanchez to ride away from the group -- Jelle is out of overall contention and Samuel, although now 6th overall, is a poor time trialist and so still needs to gain considerable time in the mountains to be considered a threat. So by cooperating the favorites obviously could have climbed faster, likely faster than Voeckler could have sustained. But dropping Voeckler wasn't the priority, since Voeckler also is considered weak in the time trial, and so I don't believe the favorites consider him a likely threat to still lead in Paris.

Science of Sport
Science of Sport plot of great VAMs in Tour history. Voeckler's 1600 on Plateau de Beille is well off the chart.

This is all deja-vu for Voeckler, who also rode to defend his yellow jersey seven years ago on the same climb. He finished that stage 13th, 4:42 behind Lance Armstrong and Ivan Basso, to just hold on to his yellow.

So what is it that allowed Voeckler to go from a rider who got dumped by close to 5 minutes by the favorites to one who was in the mix, matching their accelerations to the end?

Michele Ferrari named and popularized the use of the VAM metric: the rate of altitude gain of a rider on a climb, typically measured in meters of altitude gained per hour. It's a decent way to objectively compare rider power/mass ratios, especially when comparing climbs of a similar grade and altitude difference.

The results: Vanendert finished the climb in 46:01, a VAM of 1627 m/h. Samuel Sanchez was 20 seconds slower, then the favorites finished Samuel Sanchez was not far behind (20") and the group of favorites did it at 1600m/h (5.75 w/kg), in 46:48.

In contrast, according to Wikipedia Lance Armstrong reportedly did the climb in 45:30 in 2004, and Marco Pantani climbed it in a remarkable 43:30 in 1998. In 2004, Voeckler finished 4:42 behind Armstrong, making his time 50:12.

So it appears Voeckler was able to take 3:24 out of his time from seven years ago. But the stage in 2004 was 206 km ridden at 33.8 kph, with seven rated climbs:

2004 stage

In contrast, this year's stage, while still extremely tough, was clearly easier: 168 km with six rated climbs (CyclingNews) ridden at 32.2 kph. That's 1.6 kph slower than the 2004 stage, which had an extra category 3 climb. So it's reasonable Voeckler would be faster this time.

2004 stage

It's no surprise the speed was higher in 2004. The finishing list looks likes a who's-whom in mid-naughts doping scandles. Of the twelve riders finishing ahead of Voeckler only the last, 12th-place Stéphane Goubert, has not been involved in a major doping scandal. I think it's safe at this point to include the stage winner in the "involved" category, given the consistency and number and specificity of charges against him. So it's really remarkable Voeckler was able to hang with that crew as long as he was without totally collapsing on that final beyond-category climb.

Anyway, Voeckler's weakness is his time trial, and thus I think he has little chance to win the yellow when the Tour arrives in Paris. And while a VAM of 1600 was enough on the tactical shadow-boxing on Plateau de Beille, it's unlikely he's going to be able to follow a more sustained attack during the back-to-back big stages in the Alpes.

added : Cyclocosm has an excellent comparison of times, which differ slightly from Ferrari's (it depends on if you time the group or the individual riders, since it takes a significant time for the pack to cross the threshold of the climb).


Robert said...

Gary Gellin on San Bruno Mountain: 2002 and 2003.

In particular, recall that his time in 2003 was 6% lower than in 2002 so his 2003 VAM was 6% higher -- but since we actually have his SRM files we know power and watts/kg were almost exactly the same. I'm pretty sure you and I discussed this back in 2003. The implications for using small differences in VAM or estimated watts/kg to determine "peloton cleanliness" should be clear.

Robert said...

BTW, it's Plateau de Beille, not Belle.

djconnel said...

Thanks on the spelling correction!

Agreed: wind resistance is a large issue. Yet the pattern remains that hills are clearly being climbed slower now than they were the years up to 2009. San Bruno is particularly prone to winds: they have a huge influence there. There's a nice chart here from the Sports Science Blog. On many hills, however, the mountains diminish the ground-level wind speed, and wild variations in VAM are not observed. I don't recall ever encountering strong winds when climbing in Europe, although my experience is limited.

Samuel Sanchez was fastest up L'Alpe d'Huez this year on what was historically a very short stage, yet his VAM was in the 1580 range, well below the 1700+ numbers we saw in the Pantani-Armstrong era.

Robert said...

Well, remember that I expressly asked Gary in 2002 and 2003 to talk about the conditions and he didn't volunteer that the winds were different. This is consistent with what I've noticed from my own VE testing -- human perception of wind is way way less sensitive than the effects discernible from looking at the actual power files. That you don't remember it being especially windy while climbing in Europe is not inconsistent with that.

Two more things: first, the difference between Sanchez's VAM and the Armstrong and Pantani VAMs is about 7.5%. If we could see a 6% difference in VAM for Gary for the same watts and watts/kg, I think that speaks to the precision of the VAM measure for this particular purpose.

Second, I showed several years ago on rbr that Armstrong's estimated watts/kg on the final climb at the end of a long multi-col stage was the same as the estimated watts/kg for the next day's short climbing ITT with no preceding cols. I think the number of preceding cols can be a red herring -- it depends on the effort spent climbing those preceding cols. (This is vaguely related to why I think the current models of TSS inadequately capture fatigue and recovery, and why I think queuing or renewal models may be more appropriate).

djconnel said...

I agree ±5% are reasonable error bars on VAM estimation. That's consistent with the Sports Science chart for assumed 2.5 m/s wind speed (which is fast due to ground shear @ 1 meter).

On the weakness of TSS models... TSS tries to do too much with too little, I agree.