Thursday, July 28, 2011

VAMs on L'Alpe d'Huez in 2011 Tour de France

This year the Tour de France climbed L'Alpe d'Huez, the "Old La Honda" of the Tour.

The "official" climbs is 13.8 km long according to Wikipedia, and gains 1099 meters according to Strava, an average grade of 7.96% (the GPS recorded distance depends on trajectory through the switchbacks, for example, and in any case GPS isn't that accurate on distance along curvy routes). It was climbed during the Tour de France stage 19 this year.

The climb was complicated by riders arriving at the start in small groups. Timing thus needed to consider the finishing time, well documented by the race, but also the starting time. According to Wikipedia:

Since 1999 photo-finish has been used from 14 km. Other times have been taken 13.8 km from the summit, which is the start of the climb. Others have been taken from the junction 700m from the start.

The following times were posted as "official" by the Inner Ring on Twitter:

official times

I assume these are from the camera Wikipedia says is 14 km from the finish.

The Science of Sports Blog claims the following:
In terms of the historical context of the 2011 performances, the overall time for Contador was 41:30. Sammy Sanchez was the fastest of the day in 41:21, while Pierre Rolland, first to summit, did it in 41:52 because he started the climb with a 51 second lead (bear in mind small errors in timing off the TV).

He initiated timing at "the start banner of the climb".

The "official" times had Sanchez 41'45", Contador 41'54", and Rolland 42'22". These times lag Science of Sports' by 24", 24", and 30". If as I assume the difference is due to a 200 meter difference in start location than this corresponds to Contador and Rolland riding at 30 kph and Rolland at 24 kph, to crude precision.

So to convert the "official" times to the times for 13.8 km "chrono", I assume all riders other than Rolland rode the 200 meters at the same rate as Contador and Sanchez, taking 24 seconds. Perhaps this is optimistic for the 200 meters in many cases, but that makes it somewhat pessimistic for the time over the climb itself. However, assigning pack times to individuals, as is done here for both the start and finish of the climb, adds several seconds of error, so I would put all times here with ±5 second error bars.

So here's the results: I show rider, time, and VAM. I also calculated an estimated W/kg, but as I've described before, there's plenty of potential errors in such estimates, especially when riders draft each other. Jonathan Vaughters tweeted 5.4 W/kg for Tom Danielson, very close to my still air estimate of 5.51 W/kg, but then I read a claim this was revised to 5.7 W/kg, so take all that for what it's worth. My calculation has Sanchez at 5.67 W/kg, with numerous assumptions.
rider                  min   VAM
Samuel_Sanchez         41.35 1594.7
Alberto_Contador       41.50 1588.9
Pierre_Rolland         41.87 1575.0
Cadel_Evans            42.07 1567.5
Damiano_Cunego         42.07 1567.5
Andy_Schleck           42.07 1567.5
Frank_Schleck          42.07 1567.5
Peter_Velits           42.07 1567.5
Thomas_de_Gendt        42.07 1567.5
Tom_Danielson          42.37 1556.4
Jean-Christophe_Peraud 42.57 1549.1
Hubert_Dupont          43.22 1525.8
Rein_Taaramae          43.22 1525.8
Ryder_Hesjedal         43.22 1525.8
Ivan_Basso             43.22 1525.8
Levi_Leipheimer        43.22 1525.8
Jerome_Coppel          43.63 1511.2
Kevin_De_Weert         43.88 1502.6
Rob_Ruijgh             44.18 1492.4
Thomas_Voeckler        44.48 1482.4
Christian_Vandevelde   44.48 1482.4
Yury_Trofimov          44.48 1482.4
Arnold_Jeannesson      44.50 1481.8
Robert_Gesink          44.63 1477.4
Carlos_Barredo         44.68 1475.7
Blel_Kadri             44.90 1468.6
Remy_Di_Gregorio       45.55 1447.6
J_Blazquez_Hernandez   45.98 1434.0
Haimar_Zubeldia        46.12 1429.9
Richie_Port            46.38 1421.6
Chirs_Anker_Sorensen   46.38 1421.6
Sebastien_Minard       46.43 1420.1
Bauke_Mollema          46.43 1420.1
Christian_Knees        46.43 1420.1
Niki_Terpstra          46.72 1411.5
David_Loosli           46.80 1409.0
Egoi_Martinez          46.93 1405.0
Sandy_Cesar            46.93 1405.0
Gianni_Meersman        46.93 1405.0
Jakob_Fugelsang        46.93 1405.0
Jonathan_Hivert        47.90 1376.6
Jeremy_Roy             47.95 1375.2
If you told me a few years ago you could win the Tour with a 1570 VAM up L'Alpe d'Huez I'd have laughed at you. Sure, maybe in the Lemond-Indurain era, but not since the age of Armstrong, who revolutionized pro cycling by previewing climbs, training in the rain, and drinking Michelob Lite.

Quick plot of these results:
VAMs


For perspective, the Strava KOM is 48.75 minutes, a VAM of 1353. Even in this kindler and gentler era, the pros humble us poor weekend warriors even after having climbed the brutal Telegraph and Galabier in week 3 of a grand tour. But this is expected: it's what they do, they're probing the limits of human ability. And maybe, just maybe, they're no longer exceeding them.

3 comments:

Ryan Sherlock said...

It makes me so much more comfortable seeing those climbing speeds then when I watch highlights from (say) the 2003 Tour.

I'm a reasonable climber and to look at that, with me nicely warmed up and rested, I could hang with the fast guys for most of the climb (now, I didn't ride what came before it!) - that helps me believe in it all.

It would be great to see a TT up L'Alpe again in the Tour.

modusvelo said...

Dan, a possible clarifying reference is Chris Anker Sorensen's WKO file posted by Hunter at Training Peaks. I bracketed his official time of 46:47 on the file and got 8.433mi = 13.572km (for some reason Hunter's got all imperial units) During that time his output was 341w which if you assume his wt. @ 64kg is 5.33w/kg... Using these known data to verify whatever variables you might have to assume might be helpful. Sanchez's wt shouldn't be 1 or 2 kg off Sorensen's?

Thanks for the post. I am the guy who said hi on Sierra during AToC.

djconnel said...

Hmmm.... Wikipedia has Science of Sport's time for Contador and Sanchez, while it has 5 seconds slower for Rolland, and that page specifically claims to have times from 13.8 km out. I'll definitely need to check out Sorenson's file, although the file doesn't necessarily end at the finish line, it quite possibly extends past the finish (I know I never remember to shut off my computer at finish lines).