10:31 am - Thu, Jul 24, 2014
1 note

Preliminary Comparison 2014 vs 2013 Tour de France through stage 18

10:09 am
2 notes

Stage 18 2014 Tour de France Preliminary Performance Analysis

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9:38 pm - Wed, Jul 23, 2014
Q: Lots of interesting unscripted moments in the Tinkov interview today, don't you think?
immaculatecontraptions
9:34 pm
4:49 pm

2013 vs 2014 Tour de France Power Duration Comparison

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12:41 pm
1 note

Preliminary analysis 2014 Tour de France through stage 17

timing courtesy of @ammattipyoraily

normalized power estimates and DpVAM through stage 17

unfortunately vetoo was unable to get to the stage 16 times due to commercial break

comments to follow

10:03 pm - Tue, Jul 22, 2014
4 notes

Fitness-Fatigue Models and pVAM

pVAM is a fitness-fatigue model at it’s heart.  While not a subjective fitness-fatigue model, it sets a general baseline of expected VAM performances of the top general classification riders in grand tour stage races.  Poor showing on pVAM doesn’t mean a rider is not doped and a great showing on pVAM doesn’t mean a rider is doped.  The relation of pVAM residuals to doping is the clear delineation from the “doping” era and now in the predicted values of VAM.  The long component of fatigue should show itself over the course of a 3 week race, doped or not, just as the long component of fitness rears will show itself over 3 weeks.  The pVAM/dpVAM chart for stage 14 is disconcerting, while the stage 16 results offer some solace and hope, but they may also point to deeper darker secrets still left in the peloton and the possibility that the tour podium is only achievable in a doped state or a clean rider’s very lucky and very good fortune on flatter stages or possibility to get a long breakaway which gains a lot of time.

One day of the main GC contenders exceeding pVAM and dpVAM should never be a concern, that it happened on Stage 14 should be a slight concern despite the effect of wind and that it is a 9% difference probably can’t be attributed solely to wind.  Without this coming off as a defense of Bardet’s and TJV’s struggles on stage 16, Bardet and TJV have near identical profiles with Bardet showing slightly better ability on the climbs.  Is it odd the riders who show near identical profiles lose time on final climb of stage 16?  No, we must assume as top GC riders they have near the same ceiling in terms of fitness and ability and possibly came into the tour with similar fitness-fatigue profiles.  The oddities here are Nibali, Valverde, and Peraud.   Not so much so far for Pinot, who of Bardet and TJV was the one who looked to have the best fitness profile related to climbing.   However, was Stage 16, Pinot’s swan song.  If Pinot’s not doping, it likely is his swan song this tour and Stage 17 becomes brutal.

What remains to be seen is how much fatigue both Bardet and TJV suffered on today’s climb.  The rider who pushed the limits the most today will suffer the most tomorrow.  Bardet may very well be able to climb back into the white jersey, but it very much depends on how much Pinot pulled out of the tank on Stage 16 as one should expect Bardet, TJV, and Pinot to be shed by the 7th km up Pla D’Adet with Nibali, Peraud, and Valverde making things very tough.   Although we should see a decline in fitness from the cumulative fatigue in the race so far and from the profile of tomorrow’s stage it is possible for Nibali, Valverde, and/or Peraud to crack (doped or not) and for Bardet, Pinot, and TJV or possibly Konig to climb into podium positions (doped or not).  There should be some adherence to the fitness-fatigue model inherent in either dpVAM or pVAM by all of the top GC riders.   One must remember the short components of fitness and fatigue will always play a role over the course of a race.  The key for each rider is what did they take out of the tank the stage before and how much are they going to take out of the tank on the current stage.

We should expect the top finishing rider of the GC contenders to finish ahead of pVAM and below dpVAM for the next two stages, but the other riders should be hovering around pVAM or below it, but no one should be close to dpVAM. 

          

fantastic submission, thank you
9:59 pm
8 notes

stage 17 preview

6:53 pm - Mon, Jul 21, 2014
2 notes

5 W/kg is the New Normal (get over it!)

"Tejay pushed 338 average watts up the final climb for over 50 minutes. His cadence average was 84rpm and he maintained an average speed of 21kph. Racing at 1m85 with 68kg, Tejay averaged 228 watts with an average cadence of 76rpm."
http://www.srm.de/news/road-cycling/tour-de-france-stage-13/

Calculating that out, Tejay averaged 5 W/kg for the climb. This number could be evidence of very human levels of performance in this years Tour de France.

It could also be the nail in the coffin on the pseudoscience debate as the model estimate of 5.7 W/kg is a huge 14% off.

But there is an issue here.

Take a look at the model break down for Tejay:

4.86 W/kg are needed to overcome gravity

0.27 W/kg are needed to overcome rolling resistance

and

0.59 W/kg are needed to overcome wind resistance

Of those components 4.86 W/kg is nearly certain as gravity does not change and it was a long climb so timing and elevation change error will be negligible. Similarly rolling resistance is unlikely to be a major source of error of total error since it is such a small fraction of total resistance.

This of course means that the likely source of the error was from wind resistance due drafting or a tailwind (note that I say or rather than and since the tailwind diminishes the benefit of drafting). Starting off drafting can be eliminated as the source of error since a perfect draft would not assist against gravity or rolling resistance which alone add up to 5.1 W/kg. So therefore it must have been a tailwind. And in fact, there was a tailwind on the day. Measured at 10 m above the ground the average wind was 5 km/h. According to calculations by Fred Portelau this translates roughly to about 2.5 km/h at 2m or cyclist height.

For arguments sake, lets say that the wind was a perfect tail wind for the entire climb (in reality it can’t be) that would drop the the wind resistance from 0.59 W/kg down to 0.45 W/kg. So even allowing for an impossible “smart wind” the estimate would only come down to 5.6 W/kg.

To get down to the SRM site reported 5 W/kg there would need to be a cyclist level “smart wind” in the neighborhood of 30 km/h so that Tejay was literally blown up the mountain and that would certainly be not normal.

The point here is the methods for estimating performance aren’t perfect, but they are certainly good enough to pick up that something is way off here.

12:48 pm
Q: Millar's salary dropped by 300 percent? He was paying the team two year's salary just to ride?
Anonymous

the odd places logic leads if we bother to go

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