Power Data Estimates for the climbing stages

[Red Rick]

How much do we know about riders CdA anyway, both on roadbike and on TT bike.

 

[Nick2413]

There’s no way road bike CdA is the same as TT bike on bullhorns, so that chart should show even more benefit to TT imo.

they might as well also factor in that weird **** Vingo was doing with his knees constantly, that probably added .02

 

[Escarabajo]

How much do we know about riders CdA anyway, both on roadbike and on TT bike.

There are charts out there (internet, papers, etc) for riders CdA on roadbikes. I have not seen anything on TT just because depends on each rider position. The other factor is the frontal area which also depends on each rider body and position. For example below are some drag factors that I have used in the past obtained from some old information that I have:

	CD	Frontal Area, A
Vertical commuter	1.15	?
Bike Touring (Climbing)	1.00	?
Racing	0.88	?
TT	0.69	?
Drafting	0.5	?
Moser Bike	0.51	?

 

[roundabout]

maybe as a ballpark for frontal area

https://www.researchgate.net/figure/The-CdA-aerodynamic-drag-of-a-cyclist-on-a-standard-racing-bike-and-on-a-time-trial_fig4_330441547

 

[Krzysztof_O]

On the TT bike you can just switch to climbing on the handlebars if it gets too steep. On the handlebars the power difference shouldn't be big at all, the difference should mainly be bike weight, and Vingegaards TT bike was probably not much heavier than a road bike.

However, power loss in TT position is definitely a thing, but it's also an added edge a rider can have, especially if it it affects fatigue later in the ITT. Most riders way underperformed the numbers they would do had it been a 6km Combloux MTT on a road bike. Vingegaard is basically the only one that got close to his other numbers.

In contrast to Vingegaard is Pogacar, who probably had a heavier TT bike, causing him time loss on the first climb, who probably had more loss of power in TT position and thus had to push harder on the flat, in addition to losing time in every corner, and then on top of that had to do a bike change as well as just not having his best day.


It may not have cost Pogacar 30s because of Pogacars power loss in TT position, but if we contrast it to Vingegaard's power loss in TT position it definitely explains a large part of the delta. In the final section the s/min he loses is even bigger than in the KOM section where Pog just ships 15s changing bikes.

According to his own words Skeletor did 380 watts on the section between climbs, which is 6.33 w/kg (if he's 60 kg). Pretty monstrous for a TT bike and "holding back" (again, his own words). The last uphill section is estimated to be around 7 w/kg (his bike weight cost him some time on the steeper section but he gained aerodynamically on the shallower section so net gain/loss shouldn't be significant). Absolutely thermonuclear performance in the last 20 minutes of around 6.8 w/kg and on a TT bike. The power gap to other guys must've been big. Regardless of cumulated fatigue of his rivals it was one of the best TT performances ever in absolute terms. His first part was also very strong but he probably had some short "rest" on the downhill (which likely wouldn't be a rest for guys with non-alien anaerobic threshold).

 

[Andy schleck]

According to his own words Skeletor did 380 watts on the section between climbs, which is 6.33 w/kg (if he's 60 kg). Pretty monstrous for a TT bike and "holding back" (again, his own words). The last uphill section is estimated to be around 7 w/kg (his bike weight cost him some time on the steeper section but he gained aerodynamically on the shallower section so net gain/loss shouldn't be significant). Absolutely thermonuclear performance in the last 20 minutes of around 6.8 w/kg and on a TT bike. The power gap to other guys must've been big. Regardless of cumulated fatigue of his rivals it was one of the best TT performances ever in absolute terms. His first part was also very strong but he probably had some short "rest" on the downhill (which likely wouldn't be a rest for guys with non-alien anaerobic threshold).

He is less than 60 kg in the tour. 58/59 kg.

 

[Krzysztof_O]

He is less than 60 kg in the tour. 58/59 kg.

He looks less than 60 kg but you never know what materials he's composed of! In case of 58/59 kg we would be talking about 6.45-6.55 w/kg of "holding back". Gimme a break!

 

[Andy schleck]

https://twitter.com/x/status/1688666045433737216

View: https://twitter.com/NaichacaCycling/status/1688666045433737216


Naichaca always overestimate remco's performances. After take a photo with him, he will always put remco's performances above 8 w/kg 😂

 

[proffate]

Keegan Swenson at Leadville 100 --- power numbers are from power meter uploaded to Strava

With an average power of 346w from 9,480 to 12,424 ft, Swenson was riding at 5.3-5.4w/kg,

As per this old table:

We're looking at roughly 84% of max sea level output, being generous.

So this is effectively a 5.3/0.84 = 6.3 w/kg performance for 43 minutes in the (exact) middle of what's pretty much a 6 hour long time trial.

His efforts on the two subsequent major climbs, of 20 and 14 minutes, were roughly the same power output.

Gee I wonder why he doesn't race World Cups.

 

[Le breton]

Keegan Swenson at Leadville 100 --- power numbers are from power meter uploaded to Strava


As per this old table:

We're looking at roughly 84% of max sea level output, being generous.

So this is effectively a 5.3/0.84 = 6.3 w/kg performance for 43 minutes in the (exact) middle of what's pretty much a 6 hour long time trial.

His efforts on the two subsequent major climbs, of 20 and 14 minutes, were roughly the same power output.

Gee I wonder why he doesn't race World Cups.

Taking these tables at face value leads to funny conclusions.
If you compare acclimated vs non acclimated values in Bassett's table, you see that they differ maximally at 8000 feet,
about 2400 meters. 88,6% vs 84,2%, a difference of 4,2%.
Yet, at 14000 feet (about 4200 meters), the values are 71.4% vs 70.4%. A difference of only 1% between the 2 cases,

In my old age I'm not a good subject for such studies anymore, but in my past I've not seen much loss in power below
about 1500 meters. It's likely 3% at most for most people.
To do my own calculations I have a very easy formula which remains very close to actually measured values up to at least 4000 metres.
I simply consider that the efficiency of the human engine remains 100% up to about 1500 meters and
goes down proportionally to the air pressure above that elevation.
Hence human efficiency at altitude X above 1500 meters = Pressure at X meters a.s.l. / Pressure at 1500 meters a.s.l.

The highest I have cycled is 5240 metres. I did a stress test once at 5220 meters a.s.l.
The highest I've raced is 4300 meters (Mount Evans).

 

[Red Rick]

Taking these tables at face value leads to funny conclusions.
If you compare acclimated vs non acclimated values in Bassett's table, you see that they differ maximally at 8000 feet,
about 2400 meters. 88,6% vs 84,2%, a difference of 4,2%.
Yet, at 14000 feet (about 4200 meters), the values are 71.4% vs 70.4%. A difference of only 1% between the 2 cases,

In my old age I'm not a good subject for such studies anymore, but in my past I've not seen much loss in power below
about 1500 meters. It's likely 3% at most for most people.
To do my own calculations I have a very easy formula which remains very close to actually measured values up to at least 4000 metres.
I simply consider that the efficiency of the human engine remains 100% up to about 1500 meters and
goes down proportionally to the air pressure above that elevation.
Hence human efficiency at altitude X above 1500 meters = Pressure at X meters a.s.l. / Pressure at 1500 meters a.s.l.

The highest I have cycled is 5240 metres. I did a stress test once at 5220 meters a.s.l.
The highest I've raced is 4300 meters (Mount Evans).

Adjusting for altitude is the new hot topic in W/kg calculations for some guys. Even when the numbers you get are way too high for obvious reasons.

 

[proffate]

Taking these tables at face value leads to funny conclusions.
If you compare acclimated vs non acclimated values in Bassett's table, you see that they differ maximally at 8000 feet,
about 2400 meters. 88,6% vs 84,2%, a difference of 4,2%.
Yet, at 14000 feet (about 4200 meters), the values are 71.4% vs 70.4%. A difference of only 1% between the 2 cases,

In my old age I'm not a good subject for such studies anymore, but in my past I've not seen much loss in power below
about 1500 meters. It's likely 3% at most for most people.
To do my own calculations I have a very easy formula which remains very close to actually measured values up to at least 4000 metres.
I simply consider that the efficiency of the human engine remains 100% up to about 1500 meters and
goes down proportionally to the air pressure above that elevation.
Hence human efficiency at altitude X above 1500 meters = Pressure at X meters a.s.l. / Pressure at 1500 meters a.s.l.

The highest I have cycled is 5240 metres. I did a stress test once at 5220 meters a.s.l.
The highest I've raced is 4300 meters (Mount Evans).

Yes, your personal experience is more relevant than all the studies conducted by the armed forces and sports scientists.

Adjusting for altitude is the new hot topic in W/kg calculations for some guys. Even when the numbers you get are way too high for obvious reasons.

And what reasons would those be?

This particular thread is dedicated to numeric predictions based on our best understanding of physics and physiology. You both seem to be denying that altitude affects performance, which is a completely unsubstantiated claim. You will have to work harder to convince anyone of that.

 

[Netserk]

You seem unable to read. No one here denies that altitude affects performance.

 

[Red Rick]

Yes, your personal experience is more relevant than all the studies conducted by the armed forces and sports scientists.

And what reasons would those be?

This particular thread is dedicated to numeric predictions based on our best understanding of physics and physiology. You both seem to be denying that altitude affects performance, which is a completely unsubstantiated claim. You will have to work harder to convince anyone of that.

If you use a certain calculation, and you get a ludicrous number, you should probably question the validity of the calculation. ~6.2 for a climb starting at sea level for 45 minutes in the middle of a 6 hour gravel race is absolutely insane.

For starters, it's probably not very useful to know what the average response is to altitude, but what the entire range is.

 

[Le breton]

If you use a certain calculation, and you get a ludicrous number, you should probably question the validity of the calculation. ~6.2 for a climb starting at sea level for 45 minutes in the middle of a 6 hour gravel race is absolutely insane.

For starters, it's probably not very useful to know what the average response is to altitude, but what the entire range is.

On the subject of VO2 loss with altitude, I found an article than even Proffate could understand :

Altitude and acclimatization for the endurance athlete

For well-conditioned athletes, VO2max declines by 6-7% per 1000m gain in elevation within 24 hrs; one third of this can be recovered with 2 weeks acclimatization

thebottlecage.wordpress.com

which includes the following graph

https://thebottlecage.files.wordpress.com/2017/06/vo2max-vs-altitude-1.jpg?w=487&h=404&zoom=2

showing in red the preferred curve of the author for VO2 loss with altitude based on 146 experimental results.

I tried to include my own curve based on the formula which I gave above
human efficiency at altitude X above 1500 meters = Pressure at X meters a.s.l. / Pressure at 1500 meters a.s.l.

Funnily I find that it corresponds exactly to the thin dashed black curve that you see in https://thebottlecage.files.wordpress.com/2017/06/vo2max-vs-altitude-1.jpg?w=487&h=404&zoom=2
maybe somebody has read me even though I never published it (only mentioned it on1 forum or 2.

I was unable to include my desktop picture of said graph so I'll write the values calculated with my formula for VO2 loss

1500 m. 0%
2000 m -6%
2500m -12%
3000m - 17%
3500m - 22%
4000 m -27%
4500 m - 32%
5000 m - 36%

Above 4000 meters my formula probably overestimates the VO2 loss .

 

[proffate]

On the subject of VO2 loss with altitude, I found an article than even Proffate could understand :

Altitude and acclimatization for the endurance athlete

For well-conditioned athletes, VO2max declines by 6-7% per 1000m gain in elevation within 24 hrs; one third of this can be recovered with 2 weeks acclimatization

thebottlecage.wordpress.com

which includes the following graph

https://thebottlecage.files.wordpress.com/2017/06/vo2max-vs-altitude-1.jpg?w=487&h=404&zoom=2

showing in red the preferred curve of the author for VO2 loss with altitude based on 146 experimental results.

I tried to include my own curve based on the formula which I gave above
human efficiency at altitude X above 1500 meters = Pressure at X meters a.s.l. / Pressure at 1500 meters a.s.l.

Funnily I find that it corresponds exactly to the thin dashed black curve that you see in https://thebottlecage.files.wordpress.com/2017/06/vo2max-vs-altitude-1.jpg?w=487&h=404&zoom=2
maybe somebody has read me even though I never published it (only mentioned it on1 forum or 2.
I was unable to include my desktop picture of said graph so I'll write the values calculated with my formula for VO2 loss

1500 m. 0%
2000 m -6%
2500m -12%
3000m - 17%
3500m - 22%
4000 m -27%
4500 m - 32%
5000 m - 36%

Thanks for the data. Your own numbers are less generous than the ones I was using. The Columbine climb averages 3500m which is 22% by your figures and I only assumed Swenson was losing 16%.

The blogger you linked wrote, "This variability is a characteristic of altitude studies that makes it hard to say with specificity how a given individual will react to altitude", and I agree with that. There is individual variability that we can't nail down for Swenson (and which makes all of our personal experiences less useful than we'd like them to be). But the meta study from the blog post also found that well conditioned athletes lose more VO2 at altitude than couch potatoes do! So we have to start with the higher loss percentage as a baseline to compare against (~5%/1000m with acclimitization). That is, if we start assuming that Swenson is only losing 3%/1000m, putting his Columbine performance at a still-impressive but maybe-human adjusted 5.9w/kg, then we have to accept that he's not only very high level at sea level endurance performance but also an extreme outlier at altitude acclimatization.

If someone has characterized the variability of individual responses to altitude, that information would be great to have. However my review of the literature has thus far come up empty (granted, I spent less than an hour looking).

If you use a certain calculation, and you get a ludicrous number, you should probably question the validity of the calculation. ~6.2 for a climb starting at sea level for 45 minutes in the middle of a 6 hour gravel race is absolutely insane.

For starters, it's probably not very useful to know what the average response is to altitude, but what the entire range is.

Yes, I agree it is absolutely insane. That is why I posted it here. Is this not what the thread is for? Given that he destroyed the course record by a huge margin after riding solo for 2/3 of the race (which is in fact a disadvantage, despite this being a race ridden on MTBs), I don't think the power numbers alone beggar belief. Is your argument that no high altitude performance can ever be questioned? Why do you give him more benefit of the doubt than you give riders who are laboring under more stringent testing protocols?

 

[Le breton]

I managed to create an URL for my graph, but didn't succeed in shortening it satisfactorily.
Here it is :
I just deleted that url after succeeding in posting the graph via IMGUR with the help of Netserk.

Having lived at altitude (Bolivia 3400 and 5220m and New Mexico about 2400m) I have been interested in
the effect of altitude on performance but I know nothing about Swenson and the competition that is being mentioned here.

I add that I am still puzzled by the fact that until I was in my 60's I was very little bothered by altitude.
I do not understand why, for example, after living only at sea-level, when I moved to Bolivia at 3500m I wasn't even short of breath.
Why is it that with just a few weeks of training (being cautious) I was able to win races at 3800 m altitude against locals?
So many unanswered questions on that subject in my mind (I'm not complaining )
I remember taking my bike for a ride in La Paz (when aged 45) just after settling in the hotel coming from sea-level, without any breathing problem. I never had my hematocrits measured at altitude, at sea-level it's always been between 38% and 47% depending on fitness.
If anybody as a reference for a book or article that deals with the subject, I'm interested.
Addition : I'm usually just above 60 kg and my top VO2 max at sea-level WAS probably around 72-74 ml/mn.kg.

 

[Netserk]

I managed to create an URL for my graph, but didn't succeed in shortening it satisfactorily.

Do you have your graph as a file on your computer? If so, what file format?

If it's an image format e.g. .jpg, you can upload it directly to https://imgur.com/

If it's a graph in excel, you can take a screenshot of it and upload it (just paste it by clicking Ctrl+v while on the imgur site).

 

[Le breton]

Thanks a lot Netserk, I tried, but
I did it wrong somehow.
I'll try again later.
It's a jpeg photo right now.

https://imgur.com/eYnpmOA

View: https://i.imgur.com/eYnpmOA.jpg

 

[Netserk]

EDIT: If you open your jpeg file in paint and from there select all and copy it, you should be able to paste that to the online host.

 

[Krzysztof_O]

@proffate The fact that pros lose more at altitude actually makes sense. Human engine is consisted of many stages that include oxygen breathing, transport and utilization. Normal guy has a lot of shortcomings at various parts of this chain, while top athletes have all parts at a high level. If amount of breathed in oxygen is reduced average guy will feel the effect less due to other parts of chain being a bottleneck (mainly oxygen utilization in muscles) while for a top pro this becomes a bottleneck.

You can state it in an opposite way: pros are better at utilizing oxygen and their level rises faster than amteurs' as the amount of oxygen increases (altitude decreases)

 

[SafeBet]

I managed to create an URL for my graph, but didn't succeed in shortening it satisfactorily.
Here it is :

Spoiler

...

Man that's seriously doped URL.
No wonder it belongs in the clinic

 

[Le breton]

EDIT: If you open your jpeg file in paint and from there select all and copy it, you should be able to paste that to the online host.

Well, it worked this time. Thanks.

 

[Netserk]

Well, it worked this time. Thanks.

Good to see that it worked out!

 

[Krzysztof_O]

It can be seen that VO2max decrease is never bigger than air pressure decrease (for your info: air pressure at 1000 m is about 900 hPa (10% decrease vs sea level), at 3000 m about 700 hPa (30% decrease), at 5500 m about 500 hPa (50% decrease). It's basically proportional for lowest dots - almost linear dependency between air pressure and VO2max meaning that oxygen amount being the bottleneck in human engine.

BTW: Holly, molly! Who had a 15% VO2max decrease at circa 5200 m ASL? Superman Lopez, Superman from Krypton or some extremaly unfit fatty?