Power Data Estimates for the climbing stages

[zigmeister]

Yes, there is a difference in Sherpas is some respect regarding respiration and acid (ph) compared to other people, as well as metabolic. In other areas, the response after acclimation compared to Sherpas is not statistically different.

Seeing a Sherpa at 18,000ft carrying another man on his back that weighs 150lbs+ down a slope, tells me there is something very different about some people. Not anybody can do that, not even Froome...haha..

 

[Ney the Viking]

Just wanted to share that there is SRM data from the USA Pro Challange, for instance Voigts from yesterday amongs others.

http://www.trainingpeaks.com/av/DL3Q72SMXT2D5DMTKXBMFWBH5E

http://home.trainingpeaks.com/races/usa-pro-cycling-challenge.aspx

 

[Alex Simmons/RST]

So when performances go down, it is a sign that the peloton is cleaner (universally accepted and cited). But when it goes back up again, it doesn't tell you anything?

You confuse how one interprets climbing speeds for large number of rides and riders with how one interprets such data for one ride or one rider.

Hmmm, makes sense. Did you get your PhD from Coyle as well?

I don't have a PhD. I wasn't aware thre were given out by anyone.

Unless science can confirm that there are genetic outliers possible that have unusual quirks that allow them to ride a TdF top10 with their hemoglobin levels naturally keeping level, all this talk is nonsense anyway.

Not sure I have ever made any such inference with respect to this specific physiological response, but in general outliers exist in most things.

 

[Alex Simmons/RST]

It's not incorrect. You calculate based off VAM. If you think VAM is not about gravity, you need to rethink VAM. If you weight more or less is already reflected in your VAM. And hence the result is in he unit of watts/kg, not watts.

Weight doesn't enter the equation. That's a fact. And that's why I wonder about how outliers in weight like, Quintana and Voigt, skew the formula that's based off your average climber. The ratio of bike weight to bodyweight changes.

Weight doesn't enter equations relying on VAM to estimate power to mass ratios, but that does not make them correct.

Just because one chooses to normalise with W/kg, this does not mean total mass is not also factor in the equations. e.g. while gravity is the dominant resistance force on steep climbs, is not the only resistance force.

VAM tends to ignore such things because it's only ever intended to be a quick and dirty way to estimate W/kg.

 

[IndianCyclist]

So when performances go down, it is a sign that the peloton is cleaner (universally accepted and cited). But when it goes back up again, it doesn't tell you anything?


Hmmm, makes sense. Did you get your PhD from Coyle as well?


Unless science can confirm that there are genetic outliers possible that have unusual quirks that allow them to ride a TdF top10 with their hemoglobin levels naturally keeping level, all this talk is nonsense anyway.




pretty sure we can ban him for 2 years based off his biological passport.

That's the sad part. Science can never confirm outliers, it can detect a general pattern.

 

[Almeisan]

You confuse how one interprets climbing speeds for large number of rides and riders with how one interprets such data for one ride or one rider.

Why would you say that? Because the trends have been the same for the top3 riders and the GC riders as a whole. So even if I confused the matter, you wouldn't be able to infer it.

Weight doesn't enter equations relying on VAM to estimate power to mass ratios, but that does not make them correct.

It correctly predicts within a margin of error, with the emphasis on 'predicts' and 'margin of error'.
The guy I responded to didn't realize how the Ferrari formula works.

I don't have a PhD. I wasn't aware thre were given out by anyone.

Well, Coyle and Coggan got one. No reason why you wouldn't be able to pick one up. Not sure what they are good for, though. Having one only seems to make you a subject of ridicule.

That's the sad part. Science can never confirm outliers, it can detect a general pattern.

You mean science can never confirm there are no outliers. Otherwise, it makes no sense.

 

[Escarabajo]

You do not know what 'estimating' means?

I have a degree in physics and biology, you can link wiki pages and vaguely remember the concept of 'integral'.





Not sure if this is meant as ridicule or not.


Take Armstrong's blood passport as an example, is that a typical way in which hemoglobin values develop over a 3 week almost daily endurance competition? Or are there people who, without medical assistance, respond differently?

I actually don't believe that you have a degree in physics based on what you wrote.

Read the links that I gave you. If you knew physics you wouldn't use the VAM. I am an engineer and I have met some physicists in my life and trust me they are more picky that engineers. I am sure a Physicist would not ignore the natural laws.

 

[Almeisan]

Yeah, you are right. I can either use a formula to estimate. Or I can just grab a number right from thin air. Such a dummy I am that I didn't realize the latter is superior. Just goes to show engineers know more than you'd expect.


Also, this is all off base anyway. I was not promoting the Ferrari formula. I was just explaining that you don't use weight in that formula because the idea is that the VAM data reflects rider weight, since vertical distance is all about pulling yourself straight up against gravity and it gives an answer in the units of watt/kg.

 

[Alex Simmons/RST]

Yeah, you are right. I can either use a formula to estimate. Or I can just grab a number right from the air. Such a dummy I am that I didn't realize the latter is superior.

How does VAM to W/kg formula account for the (unknown) wind variable?

 

[Almeisan]

That's a rhetorical question that I hereby declare as having failed.

And to return the favor, what does wind have to do with rider weight? You can calculate one when you know the other? Just asking as you seem to suggest you are onto something here. Or am I wrong about you actually have a deeper point?

 

[Netserk]

Does anyone have an estimate for today's TTT?

Did Astana cross the line?

 

[Alex Simmons/RST]

That's a rhetorical question that I hereby declare as having failed.

And to return the favor, what does wind have to do with rider weight? You can calculate one when you know the other? Just asking as you seem to suggest you are onto something here. Or am I wrong about you actually have a deeper point?

Oh I understand that weight has largely been normalised out of the conversion of VAM to W/kg since changes in potential energy are the dominant energy demand factor, but there are still resistance forces (e.g. rolling resistance and changes in kinetic energy) that have a mass variable that VAM -> W/kg estimates don't account for.

They may be small, but saying "Weight doesn't enter the equation. That's a fact." is misleading. I agree it's a fact that VAM models don't account for, but it's not a physical fact.

Air resistance is not of course dependent directly on a mass variable, only to the extent that body mass has a relationship with one's aerodynamics.

 

[Almeisan]

See, you know the answers already. Asking those questions and making those comments is at least as if not more misleading than what I said.

Maybe take a look at the title of the thread.

 

[Alex Simmons/RST]

See, you know the answers already. Asking those questions and making those comments is at least as if not more misleading than what I said.

Maybe take a look at the title of the thread.

And if you read through the history of the thread I keep on suggesting that such estimates should be shown with error ranges to account for the unknowns and limitations of the methodology used.

Doing so would then be far less misleading than the precision conveyed without such data.

Else, I suggest figures be quoted to one significant digit, maybe to nearest 0.5W/kg at best, which is about the level of precision involved.

 

[Almeisan]

2% at 5.5 watt/kg is not .5 watts.

 

[Alex Simmons/RST]

2% at 5.5 watt/kg is not .5 watts.

Agree, but that's just maths. I'm talking about the physics and the assumptions used by the models.

If you mean the error in VAM to W/kg calculation is only ever +/-2%, then that simply demonstrates my point about over confidence in the implied precision. If you do not know the wind for instance, then you'll you have a far greater error, more akin to +/-0.5W/kg for even a barely noticeable breeze.

http://alex-cycle.blogspot.com.au/2013/07/windbags.html

 

[Ferminal]

With respect Alex, even the most crude calculations show no observations which are +/- 10% of an expected range for world class riders. The lowest Ferrari I can remember is ~5.0 for Stelvio which is perfectly explainable by being the penultimate stage, 2700m above sea level and post-Mortirolo and CVV softpedalling. At the other end you have ones like Verbier and PdBF which can be explained to a fair degree by the way they were raced and brevity, but may be a bit high.

The way I see it anything outside say -3% to +3% is unusual, the wind and other conditions are one such reason for difference, but there is also the ability of the rider(s), the tactics, the difficulty/position of the stage etc.

Alternatively you can look at SRM observations compared to crude calcuations and even then I'm yet to see a disparity at the margins suggested by those implied by textbook conditions. For whatever reason we do not really see this effect of wind manifested in observations of racing (could be due to low vector/distance ratios, topography, crowds/trees, drafting).

 

[Almeisan]

Most data I have seen is about 2 to 3%.

Also, margin of error goes both ways, not just down to lower wattages.

 

[Netserk]

Regarding precision:

vetooo ‏@ammattipyoraily 23 Aug

#TDF 2012, St. 11. @janibrajkovic [60 kg] - SRM vs. CPL Madeleine: 1:07:39 | -0.88% Croix de Fer: 1:04:31 | -0.82% Toussuire: 45:59 | +0.68%

 

[Race Radio]

Has this been posted yet?
http://tour-manager.freehostia.com/start.php

I think a few things are missing. Armstrong on Alp d'Huez in 2004, Ullrich on Arcalis in 1997

Still interesting stuff

 

[Netserk]

Has this been posted yet?
http://tour-manager.freehostia.com/start.php

I think a few things are missing. Armstrong on Alp d'Huez in 2004, Ullrich on Arcalis in 1997

Still interesting stuff

This makes no sense:

Rodriguez 6.2 Alp dhuez 2013
Quintana 6.17 Alp dhuez 2013

I thought Quintana was lighter than Purito.

 

[hrotha]

This makes no sense:


I thought Quintana was lighter than Purito.

Sure, which is why he produced less watts in total than Purito.

 

[Netserk]

Sure, which is why he produced less watts in total than Purito.

But he should produce more W/kg than Purito.

 

[Alex Simmons/RST]

Most data I have seen is about 2 to 3%

Most data I see here never quotes an error.

Also, margin of error goes both ways, not just down to lower wattages.

I never said it didn't.

 

[Dear Wiggo]

Quotes an error? I think you're in the wrong forum, mate.

The high falutin' toff pub is further down the road. We're mostly rough necks here.