Power Data Estimates for the climbing stages

[acoggan]

I'm not confused. His pursuit power was 570W. If I thought pursuit was 100% of VO2max I would have used 570W, not 547W.

I took a 5 minute value from the CP graph you put together.

I recognise VO2 max is 5-8 minutes, but giving him a higher VO2 max provided realistic values.

Changing his P @ VO2 max to 570/1.1 gives a P @ VO2 max of 518W, and a commensurate drop in VO2 to 79 ml/m/kg @ 23% efficiency and 76 ml/m/kg @ 24% efficiency.

That just doesn't smell right for a world class IPer to me. Boardman's VO2 was 90 m/ml/kg according to one of your posts.

570/1.2 gives a P @ VO2 max of 475W which is patently ridiculous, as he's ridden that for 19:14 on the road.

My bad, I thought you were assuming his pursuit power was 547 W for some reason. But anyway, where does the 83% value come from?

FWIW, here's how I'd work the problem:

If you assume that Wiggins derived 90% of his energy from aerobic sources during his pursuit (in keeping with Brailford's - or was it Kerrison's? - statement that he was more aerobic than average), then his power at VO2max would be 570 * 0.90 = 513 W.

In turn, based on his power-duration (actually, work-duration) relationship I posted previously, this would mean that he must be able to maintain:

100% of his VO2max for 7 min 46 s
93% of his VO2max for 20 min
90% of his VO2max for 60 min

Note that this approach requires no assumptions regarding his absolute VO2max or efficiency (or body mass), only that his gross efficiency is essentially constant across this range of intensities/durations (as it should be).

 

[acoggan]

What do you mean? Can you elaborate?

For all three riders considered each time (i.e., Rodriguez, Contador, Valverde), the estimated power is highest for stage 12, lower for stage 14, and lower still for stage 15. That could reflect the demands of competition/the length of the climbs impacting all of them roughly equally. It could also, however, reflect an inherent bias in the calculations (e.g., slight tailwind on stage 14, slight headwind on stage 15).

 

[acoggan]

I'd say that 90 +/- 5% would be a far more reasonable estimate.

To expand on that comment:

1. Subject #1 (that's me) in the paper below maintained 88% of VO2max for 75 min. Five other riders exceeded 56 min.

http://wustl.academia.edu/AndrewRCo...ed_cyclists._J_Appl_Physiol_1988_64_2622-2630

2. After I'd moved on from UT-Austin, the standard test changed from "time-to-fatigue at ~90% of VO2max" to "maximum power for 1 h". As shown in Table 4 of the study below, national caliber (but still amateur) cyclists such as Bostick, Mionske, etc., were found to be able to maintain 89% (range 85-95%) of VO2max for 1 h.

http://www.ncbi.nlm.nih.gov/pubmed/1997818

As I mentioned just up-thread, Keen estimated that Boardman maintained 90% of his VO2max during his ultimate hour record.

 

[mb2612]

For all three riders considered each time (i.e., Rodriguez, Contador, Valverde), the estimated power is highest for stage 12, lower for stage 14, and lower still for stage 15. That could reflect the demands of competition/the length of the climbs impacting all of them roughly equally. It could also, however, reflect an inherent bias in the calculations (e.g., slight tailwind on stage 14, slight headwind on stage 15).

This is always the case when one is deriving power from time though, it's why you have to look at all the days, rather than just one. It also correlates well with the difficulty of the stage though, so it intuitively feels right.

 

[the big ring]

If you assume that Wiggins derived 90% of his energy from aerobic sources during his pursuit (in keeping with Brailford's - or was it Kerrison's? - statement that he was more aerobic than average)

It was Vaughters. The same guy who said anaerobic contributions riding up a hill are significantly higher for a 20 minute climb vs a 40 minute climb.

 

[acoggan]

It was Vaughters.

Thanks. Obviously I don't follow these discussions all that closely.

 

[the big ring]

My bad, I thought you were assuming his pursuit power was 547 W for some reason. But anyway, where does the 83% value come from?

FWIW, here's how I'd work the problem:

If you assume that Wiggins derived 90% of his energy from aerobic sources during his pursuit (in keeping with Brailford's - or was it Kerrison's? - statement that he was more aerobic than average), then his power at VO2max would be 570 * 0.90 = 513 W.

In turn, based on his power-duration (actually, work-duration) relationship I posted previously, this would mean that he must be able to maintain:

100% of his VO2max for 7 min 46 s
93% of his VO2max for 20 min
90% of his VO2max for 60 min

Note that this approach requires no assumptions regarding his absolute VO2max or efficiency (or body mass), only that his gross efficiency is essentially constant across this range of intensities/durations (as it should be).

Too bad he could only sustain 85% VO2 power (ie the figure of 513W you have listed above) for a 33 minute climb.

I am curious what assumption you will create to explain that away.

When that number (6.1W/kg ie 85%) was first mentioned by Vaugthers, you responded thusly:

3. Mostly as an aside: given Wiggins' success as a pursuiter, I'd expect that his power falls off a bit more when going from 20 to 40+ min than most. (But then again, the point-of-reference here is Contador, who is known to be a more "explosive" climber than, say, Evans, so a ~10% difference may still be quite reasonable.)

Now you're saying a rider who can do 93% of an assumed VO2 max power for 18-19 minutes can do 85% for 33 minutes, but jumps back up to 90% for 57 minutes.

Magic!

Perhaps your graph is slightly broken because you used 72 x 6.1W/kg = ~475W and not 439W. Even so, something isn't right in all this.

 

[the big ring]

Thanks. Obviously I don't follow these discussions all that closely.

When it suits you. Suggesting Brailsford (sports science degree) or Kerrison (exercise phsiologist) made the claim gives far more weight to the argument than Vaughters (team owner) saying it. Given the claim was made back in 2009, it would be VERY difficult for Kerrison to make it. He was still coaching rowers and swimmers without much success.

Neither Brailsford nor Kerrison have ever posted here.

 

[acoggan]

Too bad he could only sustain 85% VO2 power (ie the figure of 513W you have listed above) for a 33 minute climb.

I am curious what assumption you will create to explain that away.

Fatigue? Heat? Tactics?

When that number (6.1W/kg ie 85%) was first mentioned by Vaugthers, you responded thusly:

Now you're saying a rider who can do 93% of an assumed VO2 max power for 18-19 minutes can do 85% for 33 minutes, but jumps back up to 90% for 57 minutes.

Magic!

Perhaps your graph is slightly broken because you used 72 x 6.1W/kg = ~475W and not 439W. Even so, something isn't right in all this.

I started with the assumption that, as a pursuiter, Wiggins had a high anaerobic capacity, and hence would experience a greater drop-off in power than someone lacking that ability. Subsequently, though, I pulled together that work-duration plot, which instead implies that (as Vaughter suggested) that he was really more of a TTer "masquerading" as a pursuiter.

In any case, I have only relied upon publicly-reported absolute power outputs, and have never made any assumptions as to how much Wiggins weighs/weighed.

 

[acoggan]

When it suits you. Suggesting Brailsford (sports science degree) or Kerrison (exercise phsiologist) made the claim gives far more weight to the argument than Vaughters (team owner) saying it. Given the claim was made back in 2009, it would be VERY difficult for Kerrison to make it. He was still coaching rowers and swimmers without much success.

Neither Brailsford nor Kerrison have ever posted here.

Paranoid much? I just forgot who made that claim/to whom it was credited.

 

[the big ring]

Paranoid much? I just forgot who made that claim/to whom it was credited.

Yeah kinda. Forsooth, thou be CogganDor, defendor of the Coyle.

What can I say. I've gone back and read your posts from that discussion and they lend credence to the doubts I have. I can pull up posts from a different discussion where you exhort us to make NO assumptions about Wiggins CdA and then go ahead and do that yourself.

Just sayin'.

 

[acoggan]

I can pull up posts from a different discussion where you exhort us to make NO assumptions about Wiggins CdA and then go ahead and do that yourself.

Only to illustrate the uncertainty involved.

 

[acoggan]

Yeah kinda. Forsooth, thou be CogganDor, defendor of the Coyle.

What can I say. I've gone back and read your posts from that discussion and they lend credence to the doubts I have. I can pull up posts from a different discussion where you exhort us to make NO assumptions about Wiggins CdA and then go ahead and do that yourself.

Just sayin'.

Only to illustrate the uncertainty involved.

Besides, since when would I need to rely upon an appeal to authority (e.g., by crediting Brailsford or Kerrison instead of Vaughters) to bolster my arguments??

 

[halamala]

Dr Michele Ferrari

Some rather good VAM performances by the best riders on the main climbs:

- Mirador de Ezaro: 2km at 12%, 2068m/h, 6.89 w/kg
- Arrate: 5 km at 8%, 1846 m/h, 6.59 w/kg
- Andorra: 7.3 km at 8%, 1740 m/h, 6.21 w/kg
- Ancares: 9.5 km at 8%, 1756 m/h, 6.27 w/kg
- Covadonga: 8.5 km at 9%, 1788 m/h, 6.16 w/kg
- Bola del Mundo: 11.4 km at 8.7%, 1666 m/h, 5.95 w/kg

http://www.53x12.com/do/show?page=indepth.view&id=133

 

[the big ring]

Fatigue? Heat? Tactics?

Ah yes. The magical defense for seeming incongruous performances. Nice try. Here's the original post from JV that provides the data for this discussion.

Ok, so answer the 20 min effort vs 40+ minute effort question, I only have limited information from elite athletes, so this isn't a University study....

That said: CVV can produce about 5.9 watts per kg in peak form for 40+ minute climbs, Wiggo is a bit more at 6.1 w/kg for this length of effort.
From the pre-Tour tests both riders have done up Rocacorba (a 33 minute climb) I know that Wiggo was at 6.1w/kg and CVV was 5.7 w/kg (He was off form a bit in June). However, Wiggo did a local 10 mile TT in GB about 2 weeks before the Tour, or 5 days before the Rocacorba test. He posted a time of 18mins flat (and was disqualified for using a 1080 wheel...funny rules over there). Anyhow, his power was 482 watts, so using his Tour weight of 72 kgs, so 6.7 w/kg. So, anecdotally, there's about a 9% decrease in power when going from a 20 min effort to a 40+ min effort. At 6.7 w/kg you certainly can climb at a VAM of 1750, but at 6.1 you wont even hit 1700 (again, anecdotal based on experience).
The last TT in the Tour Wiggo averaged 434 watts, consistent with his previous tests of 40+ minutes and just about 6.1 w/kg. I dont have any data for Wiggo up climbs in the Tour, as he didnt use a PowerTap.

JV

1. If Wiggins was fatigued, 5 days after an 18minute TT, he shouldn't be placing 4th in the Tour de France 4 weeks later.
2. If the heat was affecting Wiggins power up the climb, he shouldn't be placing 4th in the Tour de France 4 weeks later.
3. JV was testing Wiggins up the climb, there were no tactics involved. It's a test.


As JV mentions above, Wiggins did 434W for 49'10" in the final TT (40km).

What we're saying here is that between 2009 (29 years of age / 7 years in the professional peloton) and 2011 (31 years of age), Wiggins power increased by 4% (to 453W) for an increased duration of 16% (49 to 57 minutes). His P @ VO2 max is irrelevant.

Magical marginal gains!

 

[roundabout]

What did Wiggins do in Liege in the prologue? Somewhere around 500 watts? My mind could be playing tricks here, but a number may have been mentioned in one of the Wiggins/Sky threads.

Sivtsov did 446 watts "officially" and he was 4% slower.

 

[acoggan]

Ah yes. The magical defense for seeming incongruous performances. Nice try. Here's the original post from JV that provides the data for this discussion.



1. If Wiggins was fatigued, 5 days after an 18minute TT, he shouldn't be placing 4th in the Tour de France 4 weeks later.
2. If the heat was affecting Wiggins power up the climb, he shouldn't be placing 4th in the Tour de France 4 weeks later.
3. JV was testing Wiggins up the climb, there were no tactics involved. It's a test.


As JV mentions above, Wiggins did 434W for 49'10" in the final TT (40km).

What we're saying here is that between 2009 (29 years of age / 7 years in the professional peloton) and 2011 (31 years of age), Wiggins power increased by 4% (to 453W) for an increased duration of 16% (49 to 57 minutes). His P @ VO2 max is irrelevant.

Magical marginal gains!

Ah, so that's the 33 min effort to which you were alluding (I told you that I don't pay that close of attention to things...in fact, I had to go back to this thread to find my own original critical power analysis, as I didn't bother to save it).

Anyway, given that it was a training effort, another possibility is that Wiggins simply didn't give it "full stick".

 

[Krebs cycle]

I got a similar value for Brad Wiggins.

If you take Brad's weight down to 69kg, the .23/.24 efficiency values move up to 95/99 ml/m/kg. I deliberately kept it at 72kg so the hater haters don't get their knickers in a twist.

You've got a small mistake in your calculations. Looks like you've converted power @ 83% to max power and then converted to VO2max. You should convert total energy release to VO2 first and then calculate max VO2 from there, not the other way around.

Using your figures above the correct value for VO2max using 23% efficiency and 83% VO2max should be 93.6 ml/kg/min, NOT 95. However this assumes a 100% energy yield from aerobic sources which is impossible due to O2 uptake kinetics and the increase in anaerobic utilization at the end of the race. So if we assume 1% energy yield from anaerobic sources then it brings the VO2max value down to 92.7 ml/kg/min.

If we assume 88% VO2max it brings the VO2max down to 87.4 ml/kg/min.

At 22% efficiency that goes up to 91.4 ml/kg/min.

At 90% VO2max those values become 85.5 and 89.4 respectively.

If we bumped up the anaerobic energy yield to 2%, then at 90% VO2 and 23% efficiency the VO2max becomes 84.6 ml/kg/min.

Fun exercise but too many assumptions for me. Unknowns are as follows:

efficiency
%VO2max
anaerobic energy yield
exact bodyweight

where did 453W come from anyway, is that verified?

 

[the big ring]

Anyway, given that it was a training effort, another possibility is that Wiggins simply didn't give it "full stick".

Good grief. You're as unbelievable as someone else who was saying Wiggins was TTing at the UK 10mile champs and switched off when he learned that he had beaten Hutchinson (via someone yelling time splits to him from the side of the road as he raced past at 50+ km/hr), so his effort was not 100%.



You seriously expect me to beleive that 9 days out from the Tour de France when you and your team mate head out to do a test on a 33 minute climb that you just noodle along?

And JV is the one calling it a test. Not a training ride. He even excuses VDV for his poor showing - because he was unwell, not coz he was cruising it for fun. Man. At least you are consistent.

Perhaps you feel I have not refuted this 4th excuse (fatigue, heat, tactics, now "mucking around") for weird results from Wiggins. I really would love to hear a 5th.

 

[the big ring]

where did 453W come from anyway, is that verified?

Xavier, wattage groups.

 

[Krebs cycle]

Xavier, wattage groups.

link?

I'm assuming the value comes directly from Wiggins' power meter datafile?

 

[the big ring]

link?

I'm assuming the value comes directly from Wiggins' power meter datafile?

Wattage groups is a google groups you have to join. Linking it won't show you the post. He is a PhD exercise physiologist that was attached with Sky at the time. Someone else posted here that Wiggins showed his PM to everyone back at "hq" (I didn't understand the reference but can't refute it).

It was his value for the 2011 WC TT and was used by acoggan in the CP graph he put together.

 

[the big ring]

Fun exercise but too many assumptions for me. Unknowns are as follows:

efficiency
%VO2max
anaerobic energy yield
exact bodyweight

I made efficiency a variable to explore various VO2 results. I was looking for a value that said "world champion".

Anaerobic energy yield over a 57 minute TT? I am guessing if his 4:15 IP is 90% aerobic, his 57 minute TT is going to be significantly less. acoggan mentioned previously the anaerobic contribution to a 20 / 40 minute climb is negligble. I am guessing a 57 minute TT even less of a factor.

I am not looking at only one result - the 2011 WC TT in isolation - but the IP - 10 mile - 33 minute climb values. Then comparing them to the 2011 WC TT. That's where things start to look weird.

 

[acoggan]

You seriously expect me to beleive that 9 days out from the Tour de France when you and your team mate head out to do a test on a 33 minute climb that you just noodle along?

Since when is a ~95% effort in training "noodling along"??

 

[the big ring]

Since when is a ~95% effort in training "noodling along"??

You know, I find it kinda weird that there are 2 options in these 2 scenarios:

1. WC TT vs Olympic TT. Brad goes quicker. 2 choices:
a. he generated more power
b. the wind was favourable to his body shape, he tweaked his position, his equipment was better and he had lead vehicles giving a draft

2. 33 minute climb vs 57' WC TT. Brad generates more power. 2 choices:
a. he generated more power
b. heat, fatigue, tactics, "saving himself" in the 33 minute climb "test".

I know you're not really defending Brad, but it appears you cannot even begin to entertain the idea that Brad's power increased.

Shouldn't you have argued his efficiency went up by now or something?