Critical Power Study of GT Winners

[Alex Simmons/RST]

I've always thought that 40-45 minutes was the the approximate base time for "Critical Power", then you add the anaerobic work capacity to that.

If inputs to the CP model include maximal tests of ~ 3-5 minutes and ~20-25-minutes, then yes CP will be pretty close to 45-minute power, or a little over FTP. If the test durations are shorter, then CP may be closer to say 30 minute power.

Figure it'll take a minimum of 3.5 minutes to fully burn through the AWC

It is possible to "dump" AWC faster than that (e.g. I was able to reach maximal accumulated O2 deficit levels in about 75 seconds during a track time trial) but how quickly it depletes is a function of the power demand above threshold levels and individual capability to generate high power outputs relative to threshold.

That's part of the art of pacing short duration TTs. Easy to get it wrong (which is why so many pace pursuits poorly).

 

[jw1979]

normally body composition is divided into 3 categories, fat free mass (FFM), water, and fat. If you define "lean mass" as everything besides fat, then you're including water weight (bones, bowel contents, etc.). Why would anything besides actual muscle and maybe liver contain work capacity?

Also, Phil is exceptionally lean. 6% bf is an overestimate. Having raced crits with him, he's told me that he can sustain 500 watts for ages but can't hit 800 watts for 30 seconds. So whatever your calculations you use, bear in mind that for Phil, the sanity check is "really really below average AWC".

Yes, Phil is exceptionally lean, and 6% may be a slight overestimate, but only by a 1% or so, otherwise he couldn't stay healthy.

He can probably sustain 500 watts for about 5:00. That may feel like ages, but the reality is that it's only 5:00.

30 second power is not nearly long enough to exhaust AWC and is therefore not a good indicator.

Phil's AWC is quite normal, I'm confident of that.

 

[jw1979]

Well, in the link you provided below, for Sutherland, the 20 min. power was 6.1 watts, and the 1 hour or FTP was just 4.8 watts/kg. Going from 6.3 at 20 minutes to 5.8-5.9 at FTP depends a lot on your assumptions about AEC, which I will discuss below. Though I tend to think the 4.8 value does not reflect his best effort, i.e., he wasn't going all out that entire time. If you plug those numbers into the equation used in the paper, you get an estimate of AEC that seems too high.



In the study discussed in this thread, all the riders were well above 30 kj. E.g., Froome was over 100. Horner, the lowest, was about 45.



It depends on the AEC. Horner, who had the lowest estimated AEC for any of the riders in the study, had a 20 min. power of 6.3 and an estimated FTP of 5.85, in line with your estimate. But other riders had much higher AECs, and a different relationship. E.g., Contador 2009 had a 20 min power of about 6.9, but an FTP of 5.9. Froome has 6.5 and 5.6, respectively. The reason the FTPs seem unreasonably low to you is that the AECs are much higher than you are allowing for. Maybe you think they are unreasonably high, I don’t know.



No, power is proportional to climbing time, so he should be 8-10% slower. Unless the gradient is fairly shallow, and wind resistance is significant.



OK, so Porte was 10% faster. It was about 5% gradient, so there could have been some wind resistance, meaning that 10% faster means more than 10% difference in power. But there could have been drafting, too, I don't know.



This link gives his 20 min power as 6.1 watts/kg. If you add 10% for Porte you get 6.7 watts/kg., subject to assumption that wind resistance wasn't a factor. This is actually a little less than Contador 2009, who, again, had a calculated FTP of just 5.9. So again, it depends on AEC. Porte could have a very high 20 min power (but not 7.0) and still have an FTP in the range determined in this paper.

So to summarize, your main point was that the FTP values he determined are ridiculously low, and you claimed that the existence of 7.0 watts/kg efforts at 20 min. shows this. I'm not yet convinced that anyone recently has done 7.0. I don't think the Sutherland/Porte data quite establish that, and from what I've heard, Contador at TA was not close to that. More important, though, the author is arguing that FTP can be much lower than 20 min power if AEC is high, thus the example of Contador 2009 or Froome 2013. This is clearly controversial. Alex, following post, says FTP is usually within 90% of 20 min, whereas in this paper the estimates for some riders go much lower.

Rory's job didn't include having to go all out for an hour, which is why his best output for 60 minutes, from stage 5 of the race was 4.8 w/kg. I don't mean to be rude, but if you think someone with an FTP of 4.8 w/kg can do 6.15 w/kg for 21:00 you have a lot to learn in regards to power.

Climbing times are absolutely not directly proportional to power output and it's extremely naive to think wind doesn't make a difference. If someone is going uphill at 15 mph on 375w, you'd be crazy to think they'd be doing 60 mph with 2 horsepower or roughly 1500w.

Alex and I agree that FTP is roughly 90% of 20 min power, and the guy who wrote this paper is showing that he doesn't really know what he's talking about.

The study, if you want to call it that, is using CP as roughly the equivalent of 2 hour power and calculating AWC from that, which is why it's so much higher than what I'm using, and also one of the factors that is leading him to really bad data.

If Porte was drafting in the TT, I'm pretty sure he would have been disqualified or heavily penalized. Porte was within a few percent either way of 7.0 w/kg. You can believe what you want, I'll do the same.

An FTP of 5.9 w/kg taken from a climb that ends at 6000'+ is consistent with someone who can do 7.0 w/kg for 20' at lower elevations for 20:00.

There's not much controversy here, it's just what the top guys do.

 

[EnacheV]

Phil is hitting 6.3 for 20 minutes these days. There are few guys I would put my hand the fire for but Phil is one of them.

But festinaboy told me that >6 is doping. who i can believe ? serious question.

 

[Merckx index]

Rory's job didn't include having to go all out for an hour, which is why his best output for 60 minutes, from stage 5 of the race was 4.8 w/kg. I don't mean to be rude, but if you think someone with an FTP of 4.8 w/kg can do 6.15 w/kg for 21:00 you have a lot to learn in regards to power.

I don't doubt that I have a lot to learn about power, but as I said, I assumed that wasn't his best time.

Climbing times are absolutely not directly proportional to power output and it's extremely naive to think wind doesn't make a difference. If someone is going uphill at 15 mph on 375w, you'd be crazy to think they'd be doing 60 mph with 2 horsepower or roughly 1500w.

There is some wind resistance, but it is typically 15-20% at most of the total power needed to overcome it, and so one rider going a little faster than another won't expend a great deal more for this than the slower rider will. However, I checked this out using a calculator. It's actually ambiguous. If you plug in Sutherland's numbers, you don't come up with 474 watts, and there is no reasonable way you can change the parameters to get that. And some of the figures in the link are incorrect, e.g., it says the ITT was 9.6 km and he did it in 21:17, but that does not work out to 16.2 mph as they say, but 16.8. Using that, I get 415 watts. But if you plug in Richie's numbers, using 62 kg as his weight, you get 6.72 watts/kg.

I tried another calculator and got different results, but also nonsensical. At this point I give up, for now.

Alex and I agree that FTP is roughly 90% of 20 min power, and the guy who wrote this paper is showing that he doesn't really know what he's talking about.

So two guys say it's 90%, another says it's 95%, another says it can vary more than that. And one of these guys doesn't know what he's talking about. Or maybe there's just a lot of controversy over this issue.

The study, if you want to call it that, is using CP as roughly the equivalent of 2 hour power and calculating AWC from that, which is why it's so much higher than what I'm using, and also one of the factors that is leading him to conclusions different from mine.

Fixed.

If Porte was drafting in the TT, I'm pretty sure he would have been disqualified or heavily penalized. Porte was within a few percent either way of 7.0 w/kg. You can believe what you want, I'll do the same.

I didn't know it was an ITT, I don't follow all races that closely. I see that now. But as I said above, the numbers don't seem to indicate 7.0, but then again, they also don't indicate the watts figure released by Sutherland.

An FTP of 5.9 w/kg taken from a climb that ends at 6000'+ is consistent with someone who can do 7.0 w/kg for 20' at lower elevations for 20:00.

So you don't actually have a problem with this study by a guy who you said doesn't know what he's talking about, except that maybe he doesn't discuss elevation factors? Someone should have brought this up before.

 

[Race Radio]

But festinaboy told me that >6 is doping. who i can believe ? serious question.

For how long? 20 minutes, 30 minutes, or 40 minutes? Horner did 6.25 for 43 minutes.

Vayer is a funny guy but you have to take everything he says with a huge grain of salt

 

[jw1979]

I don't doubt that I have a lot to learn about power, but as I said, I assumed that wasn't his best time.



There is some wind resistance, but it is typically 15-20% at most of the total power needed to overcome it, and so one rider going a little faster than another won't expend a great deal more for this than the slower rider will. However, I checked this out using a calculator. It's actually ambiguous. If you plug in Sutherland's numbers, you don't come up with 474 watts, and there is no reasonable way you can change the parameters to get that. And some of the figures in the link are incorrect, e.g., it says the ITT was 9.6 km and he did it in 21:17, but that does not work out to 16.2 mph as they say, but 16.8. Using that, I get 415 watts. But if you plug in Richie's numbers, using 62 kg as his weight, you get 6.72 watts/kg.

I tried another calculator and got different results, but also nonsensical. At this point I give up, for now.



So two guys say it's 90%, another says it's 95%, another says it can vary more than that. And one of these guys doesn't know what he's talking about. Or maybe there's just a lot of controversy over this issue.



Fixed.



I didn't know it was an ITT, I don't follow all races that closely. I see that now. But as I said above, the numbers don't seem to indicate 7.0, but then again, they also don't indicate the watts figure released by Sutherland.



So you don't actually have a problem with this study by a guy who you said doesn't know what he's talking about, except that maybe he doesn't discuss elevation factors? Someone should have brought this up before.

The two guys that are for the most part agreeing on this have been immersed in the watts-world for 10+ years each and get paid to do just this sort of thing. I would at least consider giving what we say a little consideration.

Apologies for not being a little nicer with some of my wording.

5.9w/kg FTP and 6.9w/kg for 20:00 is only two data points that I think sound reasonable. It doesn't mean I agree with the entire study, obviously, which paints a very different picture than what I believe to be reality. He obviously put a lot of time into putting it together, and that's commendable.

 

[thehog]

But festinaboy told me that >6 is doping. who i can believe ? serious question.

You have to make your own determination.

ie Horner may do 6.2 for 13km on the Angliru and 5.88 for the total 40 minute effort. The Angliru has one very steep section at 23% and then flattens out for almost 2km. The start is not so steep either. Horner was also at “full drafting”. The stage had a 100km lead in. Compare to Ventoux and you have 220km lead in and record pass and then 55 minutes of total climbing with no flat sections like the Angliru and Froome was at 6.0. Froome was on his own from 7km – ie no drafting.

Pinot rode faster than Frome on Angliru so there’s always context. ie Froome had to lead Wiggins up the entire climb whereas Horner did not.

And that where lies the problem; a single digit can never explain the full story or whether its “doping” or “not doping”.

Horner’s climbs at the Vuelta barely got themselves over 13km and the stages were a long way short of 200km:

Pena Cabarga 6km (178km), Naraco 6km (177km), Hazallais 7.5km (186km), Angliru 13.2km (142km)

You have to also factor “altitude”. Big difference climbing at 500m above sea level than 2000m. Ross Tucker goes into a lot of analysis on this front. Worth reading.

“Now, important to realize is that on longer climbs, we would expect that the power output will be lower, and thus our expectation for VAM should also be lower. Similarly, altitude affects performance, and so the greater the altitude of a climb, the lower the predicted power output and VAM.”

The biggest issue here is the riders name and that dilutes or influences on how people judge a performance and whether they believe doping or not.

ie if you were presented with the following data;

Rider A 6.2, Rider B 5.88, Rider C 6.9

The obvious question here is you’d ask for more details on length of climb etc. etc. Your one digit won’t explain doping or not doping. That’s why Vayer’s comments per Froome at Oman were a little hasty. If you said in isolation that Rider B rode 6.88 at Oman for 20 minutes what would you thoughts be?

 

[Merckx index]

The two guys that are for the most part agreeing on this have been immersed in the watts-world for 10+ years each and get paid to do just this sort of thing. I would at least consider giving what we say a little consideration.

Believe me, I am. I’m just trying to sort out what is widely agreed on from what is controversial. I started the thread hoping to draw in this kind of feedback.

Apologies for not being a little nicer with some of my wording.

Actually, considering the way I was fumbling around at some points (I initially didn’t appreciate how much wind resistance there is at 5% gradient for pro riders; not much for me), I thought you were quite restrained. FWIW, I think you’re right about the 7+ watts/kg at 20 minutes. Certainly close in any case.

Which leads to this:

And that where lies the problem; a single digit can never explain the full story or whether its “doping” or “not doping”.

But if Porte, and presumably he’s not the only one, did 7.0 watts/kg for 20 minutes, that is very suspicious. Ross Tucker argues that > 6.2 watts/kg is very likely not sustainable without doping for climbs > 30 minutes. Even using Dauwe’s analysis, which for some riders results in estimated FTPs that are only 85% of the 20 min. power, you’re going to end up with > 6.2 for 30-40 minutes. E.g., the ratio of P40 and P30 to P20 for both Contador 2009 and Froome, which according to him had the highest AEC (and thus steepest dropoff of aerobic power over time) was about 90% and 92.5%, respectively, which would result in an estimate for Porte of about 6.30 watts at 40 min and 6.50 watts/kg at 30 min. And again, these values result from very high estimates of anaerobic energy. If you follow Alex and jw, you would expect still higher power values at these times, and a one hour time of at least 6.3 watts/kg. Coggan’s 95% would put you 6.65 watts/kg for one hour.

So it seems to me that Tucker would look at Porte’s performance there and have to conclude with high probability that he was doping. In fact, from Tucker’s point of view, a reasonable 20 min power cutoff would be around 6.5-6.6 watts/kg. By most people’s standards, that would indicate > 6.2 watts/kg at times > 30 min.

I know we have argued to death this subject of what power indicates doping, with many maintaining the line is too fuzzy to make any definitive conclusions. But I find this example very interesting, because a) we have Sutherland's power data to go along with Porte's time; and b) Tucker, whom I have a lot of respect for, has basically drawn a line in the sand here.

 

[thehog]

Believe me, I am. I’m just trying to sort out what is widely agreed on from what is controversial. I started the thread hoping to draw in this kind of feedback.



Actually, considering the way I was fumbling around at some points (I initially didn’t appreciate how much wind resistance there is at 5% gradient for pro riders; not much for me), I thought you were quite restrained. FWIW, I think you’re right about the 7+ watts/kg at 20 minutes. Certainly close in any case.

Which leads to this:



But if Porte, and presumably he’s not the only one, did 7.0 watts/kg for 20 minutes, that is very suspicious. Ross Tucker argues that > 6.2 watts/kg is very likely not sustainable without doping for climbs > 30 minutes. Even using Dauwe’s analysis, which for some riders results in estimated FTPs that are only 85% of the 20 min. power, you’re going to end up with > 6.2 for 30-40 minutes. E.g., the ratio of P40 and P30 to P20 for both Contador 2009 and Froome, which according to him had the highest AEC (and thus steepest dropoff of aerobic power over time) was about 90% and 92.5%, respectively, which would result in an estimate for Porte of about 6.30 watts at 40 min and 6.50 watts/kg at 30 min. And again, these values result from very high estimates of anaerobic energy. If you follow Alex and jw, you would expect still higher power values at these times, and a one hour time of at least 6.3 watts/kg. Coggan’s 95% would put you 6.65 watts/kg for one hour.

So it seems to me that Tucker would look at Porte’s performance there and have to conclude with high probability that he was doping. In fact, from Tucker’s point of view, a reasonable 20 min power cutoff would be around 6.5-6.6 watts/kg. By most people’s standards, that would indicate > 6.2 watts/kg at times > 30 min.

I know we have argued to death this subject of what power indicates doping, with many maintaining the line is too fuzzy to make any definitive conclusions. But I find this example very interesting, because a) we have Sutherland's power data to go along with Porte's time; and b) Tucker, whom I have a lot of respect for, has basically drawn a line in the sand here.

The thread is excellent and thanks for posting. The debate fosters thought, research and analysis by all.

I think you & I are saying the same thing. What I meant was; remove the riders name. Rider A, 20 minutes @ 7.0 - what does that tell you?

Single digit with no other data or context and it's impossible to draw a reasonable conclusion on doping.

On the above you'd still want to ask questions to obtain more information. You've provided Tuckers analysis, which is good as it helps explain the 20/7 from Porte.

Look at Pena Cabarga, it gets brought up all the time about Horner's record time and wattage and now it was faster then Froome on the same climb. On face value, then yes, it's extreme. But context is so important on that climb. Why? Because in the history of the sport it's been climbed only 3 times. Yes 3 times* and never in the doping era. It was climbed in 2010, 2011 and Horner's in 2013. So yes no wonder they were climbing records on that specific climb each time they rode it. Prior to 2010 it was impossible to even recon the climb due to ETA separatists. The other part is when Froome rode his stage, it was 30km longer, Horner had a 100km run in and a tailwind for a straight line 5km climb. Those datapoints matter and a single digit won't tell you this or the history of the specific climb. Tucker a scientist would never consider this detail but should if the comparison on wattages is taken between a climb only ridden since 2010 (Pena) and a frequently ridden Tour climb which has climbing data for 30+ years.

It also adds the other element and that's empirical observation of the performance. Froome's shock & awe performance on Ventoux is a good example. That's why there was so much debate. If you didn't see the stage and only looked at numbers it might be a different conclusion. Watching him do what he did already put the doubt in everyone's head before they knew or even saw the numbers - or even cared to see the numbers.

Similar to Porte on Ax3, he was able to lead the front group (non-drafting) from 7/8km out, then shed the lead group bar Froome and then attack again and finish 2nd! Massive red flag on that performance. Which is all based on pure observation and no numbers.


*it was climbed once also in 1979 with no timing recorded.

Peña Cabarga
2013:5,9 km@9,3%---16:42---average speed 21.20 km/h(Chris Horner)-RECORD – Stage: 186km
2011:5,9 km@9,3%---17:15---average speed 20.52 km/h(Chris Froome) – Stage: 212km
2010:5,9 km@9,3%---17:01---average speed 20.80 km/h(Joaquim Rodriguez – Stage: 178km

 

[Race Radio]

But if Porte, and presumably he’s not the only one, did 7.0 watts/kg for 20 minutes, that is very suspicious.

I have not seen any credible figures that support this number for Porte.

One thing for sure these calculations have rapidly moved out of the realm of "Pseudo Science". A guy like Vetooo used to get 2-3 files last year, now he gets dozen power files after every race. He is able to make calculations that are within 1-2% within a day of a race. Vayer's numbers are entertaining but with his generic rider weights they are usually highly inaccurate.

 

[Merckx index]

I have not seen any credible figures that support this number for Porte.

Jw provided that link to Sutherland’s power output in the uphill ITT of the 2013 P-N. Unfortunately, the (average) gradient of that ITT was relatively shallow (4.7%), which means wind resistance is significant, which in turn means that the value of body surface affects calculations a lot (and wind, of course, but one can probably assume that was about the same for both riders). Since I know the speed and power of Sutherland, I can determine a frontal surface area, but it seems very large, and that still leaves me with guessing what Porte's is. Another problem is that the gradient was not continuous, but varied quite a bit.

All we know for sure is:

a) Sutherland recorded 474 watts, which works out to 6.15 watts/kg for his reported 77 kg;
b) Porte was 10.4% faster. If you assume no wind resistance at all, the time should be very closely correlated with power inverse, which estimates Porte at 6.80 watts/kg. But since there is significant wind resistance, you might assume that Porte’s power had to be higher, since he traveled at higher speed. But against that is that he is smaller and has less frontal area. Depending on assumptions one makes, one can get values higher and lower than 6.80. But it seems to me the best assumption is that Porte's frontal surface area is about 85% of Sutherland's, based on the ratio of either their weights (about 80%) or heights (about 92%). If one assumes that, then his calculated power is way over 7.0.
c) Also, if you assume someone of Porte’s size had the same time as Sutherland (and hence same 6.15 watts/kg), then ask how much more power he would have to put out to ride 10% faster, it works out to 7.20 watts/kg. So wind resistance appears to be very significant.
d) I’ll just repeat that even 6.80, if that is valid, implies > 6.2 watts/kg at 30-40 min., which again, raises a red flag for Ross Tucker.

like to see someone who does a lot of these calculations weigh in here.

 

[Alex Simmons/RST]

Alex and I agree that FTP is roughly 90% of 20 min power, and the guy who wrote this paper is showing that he doesn't really know what he's talking about.

I say it's a range, and is dependent on the individual and their state of fitness:

The ratio of FTP to 20-minute mean maximal power is a range, usually somewhere in the 89-96% range, with 91-94% being more typical.

There are a range of factors that influence that ratio for any individual.

It can be 95% or 96% in rarer case, but there are generally people devoid of any fast(er) twitch muscle fibres. 91-94% is more typical.

The 95% ratio is oft mis-quoted and is a common misunderstanding. It's taken from a testing protocol suggested by Hunter Allen, which involves a hard 5-minute blowout effort before you do a 20-minute test effort. The 95% ratio of FTP to 20-min power is on the basis of this specific test protocol, and is intended as a guide only.

But when comparing FTP with pure 20-min MMP, then the ratio typically occurs within a range of 90% to 95%.

 

[jw1979]

like to see someone who does a lot of these calculations weigh in here.

I've done thousands of calculations with thousands of my files, files of athletes I've coached, spent way way WAY too many hours on analyticcycling.com, and gotten to the point where I can accurately convert running times into w/kg (to my own satisfaction, right?).

I realize you don't know me and therefore what I say might not hold much weight, but I can tell you 100%, my mom would totally believe me!

As a rider, I've been quite strong, though admittedly came nowhere close to mastering my diet or tactics, so ended up with zero to show for it in results. Having been to the level of 6.27 w/kg for 20:00 at 10% BF, I'm able to believe 7.00 w/kg for 20:00 is doable without drugs. IF the power stayed the same, and you take 5% BF away, that brings the level to 6.6 w/kg. That someone could be another 5+% stronger than this is something not too difficult for me to visualize.

So while some people are extremely cynical about these higher power levels, I am not one of them. Obviously there has been tons of doping in the past and plenty is still going on, but in my mind the doping happens because of the sheer volume of racing and the length of them.

Compare it to running, where top marathoners put out a maximal effort for 2:05:00, give or take a few minutes, and can handle that 2-3 times a year. But we expect cyclists to do somewhat similar efforts for something like 10 out of 20 stages of a GT. And then there are the other 50-80 race days each pro has. Obviously it's non-impact (apart from the crashes), but there is still an unreasonably amount of performances being asked of riders, IMO.

That is where the drugs probably make it possible; just the volume of racing that requires so much repeatability of maximal performances.

What I'm saying is, 7.0 w/kg for 20:00 should be expected from the best in the world as single data points here and there, just not day after day without time for the nervous system to recover.

As for the power calcs, I may have skimmed through too quickly previously.

I spoke of joules for AWC before, but think of it as watt-minutes.

For me, when my AWC is high I'm good for 600 watt/minutes when looking at time periods of 3 - 20 minutes. Beyond 20 minutes I don't have enough personal data. What I mean by that is 600 watts divided by the time period in minutes in addition to my CP 45 value.

With a peak CP45 value of 402, I would expect to hit 477w for 8:00 by adding 402w to the quotient of 600/8.

7.0 w/kg for 19:00 (for Porte) implies about 6.5 w/kg for 40-45:00 based on my experience. Further, that typically ends up around 6.25-6.33 w/kg for FTP. That is fairly standard territory for the top cyclists of the past 20+ years.

I believe one of Alex's colleagues worked with or had access to data from Chris Boardman, and reportedly saw the tests where his ramp test (going up 20w per minute) ended slightly over 600w. If his hour power was 445-455w at 69-70kgs that's only a few percent above where Porte was/is, although a totally different ballgame to actually put that power out for an hour rather than it being theoretically possible. Now, if the peloton loses Porte to osteoporosis, that would certainly cause my eyebrows to raise.

Going back to a previous point, if you've run a 5K in 18:00, it's easy to to accept others can run 17:00. If you've run a 5K in 14:00, and are not at all accustomed to losing, it may be quite difficult to accept others can run a 5K in 13:00 clean. If you run a 13:00 5K clean and got your **** kicked in foot races while growing up in the Rift Valley, it's probably easy to accept someone could run a 12:30 5K clean. So, a lot of this comes down to perspective whether you'll ever be able to believe certain data points are legitimate. My perspective tells me Ryder H. having an FTP lower than Mara Abbott isn't exactly believable, especially given the power he sustained climbing Haleakala.

 

[Alex Simmons/RST]

But I find this example very interesting, because a) we have Sutherland's power data to go along with Porte's time; and b) Tucker, whom I have a lot of respect for, has basically drawn a line in the sand here.

I personally disagree with drawing that arbitrary line and my thoughts on use of power data for this purpose are here:
http://alex-cycle.blogspot.com.au/2013/07/the-elusive-dopeometer.html

and some additional reasons why I think such an arbitrary line isn't sensible can be inferred from this item:
http://alex-cycle.blogspot.com.au/2013/08/looking-under-hood.html

for instance, refer to these two charts:

e.g. reference some "plausible" numbers for GE, VO2max and fractional utilisation of VO2max for longer duration efforts (based on the literature), and see what sustainable power output is also "plausible".

 

[proffate]

Yes, Phil is exceptionally lean, and 6% may be a slight overestimate, but only by a 1% or so, otherwise he couldn't stay healthy.

The magic minimum healthy bf number is different for different individuals.

Additionally, I think he has a low amount of muscle mass. Taylor Phinney is on record as saying he's at 4%bf at 180lbs, quite clearly packing a lot more muscle for the same amount of fat. Phil looks nothing like Taylor. Phil's low muscle mass would support the low AWC hypothesis. (You still haven't explained how bone weight increases AWC).

Phil's AWC is quite normal, I'm confident of that.

why?

 

[Race Radio]

Jw provided that link to Sutherland’s power output in the uphill ITT of the 2013 P-N. Unfortunately, the (average) gradient of that ITT was relatively shallow (4.7%), which means wind resistance is significant, which in turn means that the value of body surface affects calculations a lot (and wind, of course, but one can probably assume that was about the same for both riders). Since I know the speed and power of Sutherland, I can determine a frontal surface area, but it seems very large, and that still leaves me with guessing what Porte's is. Another problem is that the gradient was not continuous, but varied quite a bit.

All we know for sure is:

a) Sutherland recorded 474 watts, which works out to 6.15 watts/kg for his reported 77 kg;
b) Porte was 10.4% faster. If you assume no wind resistance at all, the time should be very closely correlated with power inverse, which estimates Porte at 6.80 watts/kg. But since there is significant wind resistance, you might assume that Porte’s power had to be higher, since he traveled at higher speed. But against that is that he is smaller and has less frontal area. Depending on assumptions one makes, one can get values higher and lower than 6.80. But it seems to me the best assumption is that Porte's frontal surface area is about 85% of Sutherland's, based on the ratio of either their weights (about 80%) or heights (about 92%). If one assumes that, then his calculated power is way over 7.0.
c) Also, if you assume someone of Porte’s size had the same time as Sutherland (and hence same 6.15 watts/kg), then ask how much more power he would have to put out to ride 10% faster, it works out to 7.20 watts/kg. So wind resistance appears to be very significant.
d) I’ll just repeat that even 6.80, if that is valid, implies > 6.2 watts/kg at 30-40 min., which again, raises a red flag for Ross Tucker.

like to see someone who does a lot of these calculations weigh in here.

Sorry, but I don't think this is right. Sky gave his numbers that day, Porte average 416 watts on the first half of Col de Eze and 384 on the second half and most calculations support those numbers. Porte was 63 kg at 2013 Paris-Nice http:/www.cyclingweekly.co.uk/news/latest-news/richie-portes-high-hopes-for-tour-de-france-32689. That is 6.35? Makes sense as Talansky was 6.25 that day and he was only 23 sec back

https://twitter.com/Vaughters/status/311126718867988480

 

[Mr.38%]

Really, really awesome discussion.

 

[Ripper]

Jw provided that link to Sutherland’s power output in the uphill ITT of the 2013 P-N. Unfortunately, the (average) gradient of that ITT was relatively shallow (4.7%), which means wind resistance is significant, which in turn means that the value of body surface affects calculations a lot (and wind, of course, but one can probably assume that was about the same for both riders). Since I know the speed and power of Sutherland, I can determine a frontal surface area, but it seems very large, and that still leaves me with guessing what Porte's is. Another problem is that the gradient was not continuous, but varied quite a bit.

Sorry, but I don't think this is right. Sky gave his numbers that day, Porte average 416 watts on the first half of Col de Eze and 384 on the second half and most calculations support those numbers. Porte was 63 kg at 2013 Paris-Nice http:/www.cyclingweekly.co.uk/news/latest-news/richie-portes-high-hopes-for-tour-de-france-32689. That is 6.35? Makes sense as Talansky was 6.25 that day and he was only 23 sec back

https://twitter.com/Vaughters/status/311126718867988480

While I generally think something is going on with some Sky riders, I would agree with RR that you're not quite accurate in your estimates. We know that Sutherland is not only heavier than Porte, but he's a fair bit bigger. The wind resistance in a TT where the avg gradient is less than 5% would be quite critical and aerodynamics come into play. As in, less frontal area can result in less effort to push the same speed. Given we have numbers for Porte's power and can determine his speed, one could look at the where aerodynamics come into play (I'm not about to do that here, but I am sure someone else can ).

Porte could have a slightly higher power to weight than Rory which, in conjunction to better aerodynamics on the day, could make the all the difference. In other words, Porte could be much closer to 6.35 than 6.8.

Of course, this all assumes that reported weights and wattages are accurate ... and we know that rider weights are always reported accurately

 

[thehog]

Of course, this all assumes that reported weights and wattages are accurate ... and we know that rider weights are always reported accurately

True. On an empirical view of that day, Porte noticeably gets a call in from the car to slow down. He does appear to softpedal the last 2km and corners. But this is open for interpretation and by then had the race won.

I'm sure Kerrison had his weight correctly set and knew exactly what was unfolding. Sean Kelly who knows the climb well was having a laugh at the split times displayed.

Maybe someone can link the stage. It's a nice comparison with Wiggins the year before because he was clearly going balls to the wall.

 

[Race Radio]

THe does appear to softpedal the last 2km and corners. But this is open for interpretation and by then had the race won..

Sean Kelly who knows the climb well was having a laugh at the split times displayed.

Softpedal? The last 2 km is false flat

Kelly was likely laughing because none of them beat his time from 1986, when the course was 10km not 9.6km

 

[Cyivel]

Well Kelly was surprised and said 'can that be right' and they were questioning whether the split time was accurate, not sure how much him doing that means in the grand scheme of things though.

 

[thehog]

Well Kelly was surprised and said 'can that be right' and they were questioning whether the split time was accurate, not sure how much him doing that means in the grand scheme of things though.

Yes, it's open for interpretation like I said. It wasn't posted to cause controversy.

Everyone has there own eyes and can draw their own conclusions. The point I was making that observation as well as numbers tells the story.

I'll leave cognitive bias theories for another time!

 

[Race Radio]

Yes, it's open for interpretation like I said. It wasn't posted to cause controversy.

Everyone has there own eyes and can draw their own conclusions. The point I was making that observation as well as numbers tells the story.

I'll leave cognitive bias theories for another time!

Could you show us where he was 'Soft pedaling" in his 53x12 on the false flat? Is getting out of the saddle to sprint for the line "soft pedaling"?

http://youtu.be/13Creb9iy90?t=55m48s

 

[thehog]

I believe the Eurosport footage was referenced per Kelly and observed soft pedal.

(http://www.youtube.com/watch?v=szLKrvffl4A&sns=em)

My view would be better for others to contribute, if they shall chose. I'd not like to see an excellent thread be derailed by a competitive posting matchplay.

Interpretation is open for all and all welcome to post their own views on the footage.