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The Powermeter Thread

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May 13, 2011
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Quote:
Originally Posted by FrankDay View Post
"Are you trying to imply that cyclists were unaware of the advantages of drafting before the advent of the power meter? I mean that is interesting information but, again, to what end? Is the advantage any more or less to a rider who doesn't have a PM on his bike?"


Yes Frank people have know about drafting probably since the first two bicycles rode closely in single file. What's interesting about this test was that previously it had been thought that there was virtually no draft at a distance of 12 meters between two cyclists. This had been studied in a wind tunnel where they saw virtually no draft at that distance. Well gosh here's a place where a power meter was a way better tool than the expensive wind tunnel. A near 30 watt reduction in power required when drafting a much smaller person with a good position at 12 meters is very significant.

OK now you ask how this information could be any more use to someone riding with a power meter than one without. You're a pro triathlete sitting in at 12 meters from the rider ahead of you. You're riding along holding a pretty constant 78% of FTP power. You wonder if you should pass and ride away from the person ahead. Knowing that it will require 30 more watts to ride with your face in the wind and this will put you at 87% of your FTP to do this is useful info. If from previous rides you know you can only maintain at more 79% of FTP for the duration of an IronMan you will probably decide to sit in at 12 meters and save you legs for the run.

Now a guy without a power meter having the same level of fitness isn't going to be in such an informed situation. His level of perceived exertion especially early on may tell him "this is too easy, I can ride away from this guy no sweat". If he makes this choice it's very likely to come back and bite him in the ****.

So go ahead and shoot down this scenario . I'm sure you can rationalize view against it.

Hugh

Still waiting for a response on this.
 
Mar 18, 2009
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sciguy said:
What's interesting about this test was that previously it had been thought that there was virtually no draft at a distance of 12 meters between two cyclists. This had been studied in a wind tunnel where they saw virtually no draft at that distance.
Data?

(I recall some tests in the GM wind tunnel in which Tom Demerly was somehow involved, but IIRC they didn't support the above conclusion even though that was the one that was drawn.)
 
May 13, 2011
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acoggan said:
Data?

(I recall some tests in the GM wind tunnel in which Tom Demerly was somehow involved, but IIRC they didn't support the above conclusion even though that was the one that was drawn.)[/QUOTe

Aha, Yes it was the GM wind tunnel study that Tom Demerly was involved with that stuck in the back of my brain. To be honest I never saw the actual data ..... just the conclusion Tom and the triathlon group came up with. Off to do a little Slowtwitch search.

Update from a quick search:
Well it would appear that my hair isn't the only thing I'm losing. In the one post regarding this that I was quickly able to find Tom mentions that "There was a measureable advantage to the trailing rider even while observing the three bike length rule according to the tests." The link to WTC's take on the study is now broken but I believe that in it they used the extremely small draft effect at the 3 bike length distance as the reason for choosing it.

Thanks for the correction.

Hugh
 
Jun 14, 2009
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acoggan said:
The Canadians used such data to help decide the order of the women's team pursuit squad. (Meanwhile, the US and Aussie teams were looking for wind tunnels big enough to allow them to answer the same question.)
That was a very cool and tricky piece of analysis.
 
Mar 10, 2009
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acoggan said:
The Canadians used such data to help decide the order of the women's team pursuit squad. (Meanwhile, the US and Aussie teams were looking for wind tunnels big enough to allow them to answer the same question.)

With pursuit teams riding almost wheel to wheel, how could this information give an advantage.
 
May 13, 2011
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coapman said:
With pursuit teams riding almost wheel to wheel, how could this information give an advantage.
The data they used was for the specific riders riding wheel to wheel. They were able to model the best way to use each rider based on how much draft they provided to people behind them along with the specific power and endurance characteristics of each. So they could choose the rider order and length of pulls to optimize time for the race.

Hugh
 
Jun 14, 2009
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sciguy said:
So they could choose the rider order and length of pulls to optimize time for the race.
Right. It couldn't have been done with HRMs, or with just a wind tunnel alone. It was a very nice, very tricky, piece of analysis that relied on data from several tests with power meters in various ways. Canada won bronze by the narrowest of margins.
 
Sep 23, 2010
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OK now you ask how this information could be any more use to someone riding with a power meter than one without. You're a pro triathlete sitting in at 12 meters from the rider ahead of you. You're riding along holding a pretty constant 78% of FTP power. You wonder if you should pass and ride away from the person ahead. Knowing that it will require 30 more watts to ride with your face in the wind and this will put you at 87% of your FTP to do this is useful info. If from previous rides you know you can only maintain at more 79% of FTP for the duration of an IronMan you will probably decide to sit in at 12 meters and save you legs for the run.

Now a guy without a power meter having the same level of fitness isn't going to be in such an informed situation. His level of perceived exertion especially early on may tell him "this is too easy, I can ride away from this guy no sweat". If he makes this choice it's very likely to come back and bite him in the ****.

So go ahead and shoot down this scenario . I'm sure you can rationalize view against it.

Hugh

Still waiting for a response on this.[/QUOTE]
It sure is humbling to be so far off on the utility of this device.

Hmmmmm. Wait a minute. Your scenario requires a pro triathlete and for the pro triathlete to pretty much ignore any other issues that might be involved in that decision (How good a runner am I? Do I need a big lead or not? How am I feeling today? etc.). So, while that scenario does present a possible advantage for the athlete for having a PM over not having one I am still left with a few questions.

1. How big of an advantage is that?
2. How many athletes who have PM's does that scenario apply to? 0.00001%

Now, before you think I am completely dissing the tool I am not as I am sure you can come up with some other scenarios where one might be able to see an advantage to having that information. But, regardless of the scenario, I will always be left with the above two questions plus the question: Has the presumed advantage actually been demonstrated?
 
Sep 23, 2010
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sciguy said:
OK now you ask how this information could be any more use to someone riding with a power meter than one without. You're a pro triathlete sitting in at 12 meters from the rider ahead of you. You're riding along holding a pretty constant 78% of FTP power. You wonder if you should pass and ride away from the person ahead. Knowing that it will require 30 more watts to ride with your face in the wind and this will put you at 87% of your FTP to do this is useful info. If from previous rides you know you can only maintain at more 79% of FTP for the duration of an IronMan you will probably decide to sit in at 12 meters and save you legs for the run.

Now a guy without a power meter having the same level of fitness isn't going to be in such an informed situation. His level of perceived exertion especially early on may tell him "this is too easy, I can ride away from this guy no sweat". If he makes this choice it's very likely to come back and bite him in the ****.

So go ahead and shoot down this scenario . I'm sure you can rationalize view against it.

Hugh

Still waiting for a response on this.
It sure is humbling to be so far off on the utility of this device.

Hmmmmm. Wait a minute. Your scenario requires a pro triathlete and for the pro triathlete to pretty much ignore any other issues that might be involved in that decision (How good a runner am I? Do I need a big lead or not? How am I feeling today? etc.). So, while that scenario does present a possible advantage for the athlete for having a PM over not having one I am still left with a few questions.

1. How big of an advantage is that?
2. How many athletes who have PM's does that scenario apply to? 0.00001%

Now, before you think I am completely dissing the tool I am not as I am sure you can come up with some other scenarios where one might be able to see an advantage to having that information. But, regardless of the scenario, I will always be left with the above two questions plus the question: Has the presumed advantage actually been demonstrated?
 
Jun 14, 2009
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acoggan said:
Why not? For Project 96 they did just that.
I don't know what they did for Project 96 but this particular analysis included not just order-dependent drag parameters but also a (simplified) renewal model that was order-dependent.
 
Sep 23, 2010
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42x16ss said:
Contador on yesterday's stage of Tirreno-Adriatico:

http://www.cyclingquotes.com/news/contador_it_is_important_to_see_the_working_system_of_team_sky/

“Regardless of the result this race is really good for me because I have seen the working system of Team Sky on TV, but never in reality," Contador told. "Now I have been able to see the numbers and the SRM. I think this will help me to plan the tactic in the Tour."

Now Contador knows what power he has to do to keep up with and possibly defeat Froome, he can plan his preparation for the Tour de France that bit better.

Just one application for a PM
"I think (read, hope) this will help me to plan the tactic in the Tour."

It is cool that he has this information. It is also cool that this power information is available to us all. But, there is no evidence that having this information will help him to turn out better than if he just went and did lots of hill repeats or something else. Of course these guys are trying to maximize power in July but does knowing what the power number is now or then help towards that end? Perhaps, perhaps not. That is the problem.
 
Apr 21, 2009
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FrankDay said:
But, there is no evidence that having this information will help him to turn out better than if he just went and did lots of hill repeats or something else.
What if those hill efforts were making him less powerful, what if he was doing them on climbs that were different to the Tour. Lance always made a point of riding all the climbs and TT courses in the Tour, repeatedly, measuring power, being specific, testing if he was making progress. Gaining confidence that come July he had the necessary physiological ability to win. When Cadel won he had raced the TT course at the Dauphine, measuring the power among other things, at the Tour Andy Schleck hadn't even looked at the course and suffered one of his biggest TT defeats. There is plenty of evidence that riders use a power meter as a measurement device as part of the performance process leading into major races.

Of course these guys are trying to maximize power in July but does knowing what the power number is now or then help towards that end? Perhaps, perhaps not. That is the problem.
No problem, these guys and their coaches understand power.
 
Mar 10, 2009
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sciguy said:
The data they used was for the specific riders riding wheel to wheel. They were able to model the best way to use each rider based on how much draft they provided to people behind them along with the specific power and endurance characteristics of each. So they could choose the rider order and length of pulls to optimize time for the race.

Hugh

I thought ye were referring to the 12 m. drafting advantage.
 
Sep 23, 2010
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CoachFergie said:
What if those hill efforts were making him less powerful, what if he was doing them on climbs that were different to the Tour. Lance always made a point of riding all the climbs and TT courses in the Tour, repeatedly, measuring power, being specific, testing if he was making progress. Gaining confidence that come July he had the necessary physiological ability to win. When Cadel won he had raced the TT course at the Dauphine, measuring the power among other things, at the Tour Andy Schleck hadn't even looked at the course and suffered one of his biggest TT defeats. There is plenty of evidence that riders use a power meter as a measurement device as part of the performance process leading into major races.



No problem, these guys and their coaches understand power.
There are lots of things these folks do to try to optimize their chance of winning and to optimize their power, including both Lance and Cadel paying attention to pedaling technique, something you snicker at. Just because they also have a power meter is not evidence that having that power meter is the reason for their success or that, even, that power meter even contributed to their success.

So, while I agree that with your statement "There is plenty of evidence that riders use a power meter as a measurement device as part of the performance process leading into major races" I simply am not convinced that there is any evidence that their using a power meter as part of their preparation made any real difference in how they ultimately performed if they had chosen to not use the tool. Most of those same people also use my product yet you steadfastly refuse to believe that such use means anything. What is different about the power meter?
 
Apr 21, 2009
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coapman said:
I thought ye were referring to the 12 m. drafting advantage.
Also referring to the Australians who got all four of their Teams Pursuit riders in the wind tunnel to measure their aerodynamics. Andy has mentioned the US TP did this in 1996.
 
May 13, 2011
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FrankDay said:
It sure is humbling to be so far off on the utility of this device.

Hmmmmm. Wait a minute. Your scenario requires a pro triathlete and for the pro triathlete to pretty much ignore any other issues that might be involved in that decision (How good a runner am I? Do I need a big lead or not? How am I feeling today? etc.). So, while that scenario does present a possible advantage for the athlete for having a PM over not having one I am still left with a few questions.

1. How big of an advantage is that?
2. How many athletes who have PM's does that scenario apply to? 0.00001%

Now, before you think I am completely dissing the tool I am not as I am sure you can come up with some other scenarios where one might be able to see an advantage to having that information. But, regardless of the scenario, I will always be left with the above two questions plus the question: Has the presumed advantage actually been demonstrated?
1. The power advantage measured sitting in at a legal 12 meters behind a diminutive rider in a good aero position was on the order of 30 watts which would be 8.6% for someone with an FTP of 350 watts. The following rider was a much larger individual. Certainly not chicken feed.

2. There is no need to be a pro to realize the same advantage here so this type of information would be useful to anyone with a power meter who wishes to have the best result possible.

Your "having a good day scenario" is the kind of magical thinking that so many amateur and even pro athletes suffer from. Just take a look at distance running events and see how consistent the race times are with expectations. If anything, one is a lot more likely to suffer a bad day and fall apart by overdoing early on when RPE is shouting "this is so easy"
 
Apr 21, 2009
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FrankDay said:
There are lots of things these folks do to try to optimize their chance of winning and to optimize their power, including both Lance and Cadel paying attention to pedaling technique, something you snicker at.
Yes, Cadel did a lot of riding on a fixed gear bike under the guidance of Also Sassi. He also measured his training and racing with a power meter.

A lot of claims made by Lance and his support crew. Also claimed he never did drugs but next minute he is on Oprah admitted we shouldn't have "believed". There is no evidence that even if he thought he was training pedalling technique that he actually was. There is plenty of video evidence that he rode the courses of the Tour and raced and trained with a power meter and did use that information in his preparation for the Tour (among other forms of preparation).

Just because they also have a power meter is not evidence that having that power meter is the reason for their success or that, even, that power meter even contributed to their success.
That is correct Frank. A measurement device measures the process, progress and in this case the cycling specific fitness but does not cause it. That is why we train.

So, while I agree that with your statement "There is plenty of evidence that riders use a power meter as a measurement device as part of the performance process leading into major races" I simply am not convinced that there is any evidence that their using a power meter as part of their preparation made any real difference in how they ultimately performed if they had chosen to not use the tool.
As I said above that is because a measurement tool doesn't improve performance. It <pause for effect> measures it!

Most of those same people also use my product yet you steadfastly refuse to believe that such use means anything. What is different about the power meter?
This is a power meter thread, keep on topic Frank.
 
Sep 23, 2010
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sciguy said:
1. The power advantage measured sitting in at a legal 12 meters behind a diminutive rider in a good aero position was on the order of 30 watts which would be 8.6% for someone with an FTP of 350 watts. The following rider was a much larger individual. Certainly not chicken feed.

2. There is no need to be a pro to realize the same advantage here so this type of information would be useful to anyone with a power meter who wishes to have the best result possible.

Your "having a good day scenario" is the kind of magical thinking that so many amateur and even pro athletes suffer from. Just take a look at distance running events and see how consistent the race times are with expectations. If anything, one is a lot more likely to suffer a bad day and fall apart by overdoing early on when RPE is shouting "this is so easy"
Sorry, the drafting power advantage is there whether one has a pm on the bike or not. You were using the scenario of a pro using the information as to where they were in relation to their FTP to help them make the decision as to whether to pass (and lose the advantage) or not. The average age grouper triathlete isn't faced with such decisions as the course where they are is usually so crowded that even if they pass they will soon be in another drafting situation so that specific decision is never encountered.
 
Apr 21, 2009
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sciguy said:
1. The power advantage measured sitting in at a legal 12 meters behind a diminutive rider in a good aero position was on the order of 30 watts which would be 8.6% for someone with an FTP of 350 watts. The following rider was a much larger individual. Certainly not chicken feed.

2. There is no need to be a pro to realize the same advantage here so this type of information would be useful to anyone with a power meter who wishes to have the best result possible.

Your "having a good day scenario" is the kind of magical thinking that so many amateur and even pro athletes suffer from. Just take a look at distance running events and see how consistent the race times are with expectations. If anything, one is a lot more likely to suffer a bad day and fall apart by overdoing early on when RPE is shouting "this is so easy"
Very good and valid reasons to train and race with a power meter.

I have a woman building up for a hilly 110km fun ride. She has a SRM and has employed me to train her for the event. We have tested in the field regularly. The lab based testing she did (lactate, power from a Velodyne and HR) gave us HR and training zones that were far too easy compared with the power data from actual training and racing.

I have given her targets to try and meet for hill intervals and we have used the data to plan her race. It is also convenient that I have the race winner data from the previous year to illustrate a winning model (not saying it was a perfect mode as this rider made mistakes as well) so she knows to pace on each of the climbs and over the whole event.

We are also using the power from hill efforts to see if she is making progress and the Performance Manager in WKO+ to keep a track of fitness gains and check for accumulating fatigue. Notable that Team Sky among others follow a very similar process.
 
Apr 21, 2009
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FrankDay said:
As I said, what is different about the power meter?
There is scientific validation that a power meter (SRM and Powertap) do indeed measure power as claimed.

Is it SRM, Powertap, Quarq etc's issues that some people actually believe a power meter is going to ride the bike for them?
 
Apr 21, 2009
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FrankDay said:
Sorry, the drafting power advantage is there whether one has a pm on the bike or not.
That is correct Frank. But how do we know it is there in the first place if we don't measure it and how do we know the difference in a Teams Pursuit between sitting 1cm off the wheel and .5 metre off the wheel so we can know whether sitting closer to the wheel is something we need to spend time coaching.

There are many things in aerodynamics that seemed to be self evident but with measurement has proved otherwise.
 
Mar 18, 2009
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FrankDay said:
"I think (read, hope) this will help me to plan the tactic in the Tour."

It is cool that he has this information. It is also cool that this power information is available to us all. But, there is no evidence that having this information will help him to turn out better than if he just went and did lots of hill repeats or something else. Of course these guys are trying to maximize power in July but does knowing what the power number is now or then help towards that end? Perhaps, perhaps not. That is the problem.
Other than doping, power was a big determinant to how Floyd Landis's magic performance on stage 17 of the 2006 TdF played out. His power output was a key factor in determining whether he would survive or not, and whether he would triumph. From this link http://le-grimpeur.net/blog/archives/27:

“A closer look at the data, however, shows that Floyd’s performance that day was well within his physical and mental capacity,” said coach Dr. Allen Lim. “In fact, the most important contributors to Floyd’s comeback was the tactics that developed during the ride – the hesitation by the peloton to chase and Floyd’s intelligent use of water.”

Landis had previously used a power meter in the 2005 Tour and Lim had published all his performance data. Analyzing his stage 17 results in 2006, Lim concluded that “Floyd averaged 281 watts for the entire 5 hour and 23 minute ride”. He went on to add that, “In training before the Tour and even before the Tour of Georgia, Floyd would regularly perform 6-hour rides at 300-310 watt averages.”

Lim also pointed to other figures: “As a point of reference, the overall average for the mountain days in the 2006 Tour de France was 269 watts +/- 16 watts [253-285], while the average in the 2005 Tour de France for the mountains was 274 watts +/- 20 watts [254-294].”

Going into the stage, Lim calculated that if Landis produced 380 watts on the climbs he would stay with the field; anything over and he would put time into them. Producing 370 watts would mean losing time. Using Landis’s stage 17 data, Lim published the following figures for the climbs.

* Col des Saises: 36 min 55 sec at 395 watts (gains time on field)

* Col des Aravis: 16 min 49 sec at 371 watts (loses time on field)

* Col de la Colombiere: 27 min 45 sec at 392 watts (gains time on field)

* Cote de Chatillon: 11 min 7 sec at 374 watts (loses time on field)

* Col de Joux-Plane: 37 min 34 sec at 372 watts (loses time on field)

Comparing the power data above to Landis’s performance in 2005 is illustrative. His best performance was on the mountains stage in the Alps, stage 11 to Briancon where he averaged 285 watts. In two tough consecutive days in the Pyrenees, stages 14 and 15, perhaps more comparable to stage 16 and stage 17 in 2006, for example, Landis averaged only 262 and 249 watts – the second day to Pla d’Adet showing the strain of consecutive stages.

Lim’s data for stage 17 shows several impressive power performances for periods over 30 minutes – 395 watts on the Col des Saises, 392 watts on the Col de la Colombiere, and 372 watts on the Col de Joux Plane. In 2005, on stages 14 and 15, his 30 minute peak power performances were 379 watts and 361 watts. It was these repeated efforts on the stage 17 climbs that were the winning formula.
 

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