The Powermeter Thread

[acoggan]

Does this explain the 8 month slip on WKO 4?

No relationship whatsoever.

 

[Retro Trev]

Yes. It says that it is a semi-quantitative tool the application of which is as much art as it is science.

At best approximate and as much art as science, at worst misleading and a waste of time.

 

[acoggan]

At best approximate and as much art as science, at worst misleading and a waste of time.

A good carpenter never blames his tools.

 

[Retro Trev]

A good carpenter never blames his tools.

Good carpenters do not use sub standard tools.

 

[acoggan]

Good carpenters do not use sub standard tools.

You're right.

 

[CoachFergie]

Righty, back from Leeds. 40-44hrs total and 24hrs in a plane. Won't be doing a trip like that too often and not surprising full of the flu on my return.

As is the aim of any Masters level project, it's about learning about the scientific process and my research has spawned more questions than answers. My short presentation was well received.

The big thing is max mean powers are not a good way to assess performance in a cycle race, even time trials but once I adjusted for repeated time trial performances of a similar distance I was left with only data from 7 of the original 25 subjects.

Dr Simon Jobson who chaired the session asked what my gut was and my response was that the performance manager model works but will be very difficult to mathematically model. But because something is a challenge is certainly no reason to give up.

Thanks to those like Andy who have contributed positively to the debate.

 

[Retro Trev]

Yes. It says that it is a semi-quantitative tool the application of which is as much art as it is science.

(FWIW, I've got some other ideas re. why Fergie failed to detect any relationships between CTL, ATL, and/or TSB and performance, but I'll share those w/ him privately so he has a chance to look at the numbers first.)

As much art as it is science. Agreed. The best artists have a good understanding of the applicable science.

 

[Retro Trev]

Righty, back from Leeds. 40-44hrs total and 24hrs in a plane. Won't be doing a trip like that too often and not surprising full of the flu on my return.

As is the aim of any Masters level project, it's about learning about the scientific process and my research has spawned more questions than answers. My short presentation was well received.

The big thing is max mean powers are not a good way to assess performance in a cycle race, even time trials but once I adjusted for repeated time trial performances of a similar distance I was left with only data from 7 of the original 25 subjects.

Dr Simon Jobson who chaired the session asked what my gut was and my response was that the performance manager model works but will be very difficult to mathematically model. But because something is a challenge is certainly no reason to give up.

Thanks to those like Andy who have contributed positively to the debate.

Do you have the heart rate data to look at in conjunction with the power data?

 

[acoggan]

Righty, back from Leeds. 40-44hrs total and 24hrs in a plane. Won't be doing a trip like that too often and not surprising full of the flu on my return.

I was going to hold my piece while you recovered from the flu, but since you're posting despite your illness...

In addition to the question I emailed you about looking at the relationship only w/in a given individual, here are a few other questions/comments I had:

1) I noticed that the abstract refers to attempting to correlate CTL, ATL, or TSB on the previous day w/ performance on any given day. That would be appropriate for CTL and ATL, but not TSB as extracted using WKO+, since the latter is deliberately offset by one day into the future (the rationale being that you typically want to know your TSB just before you train or race, not afterwards). IOW, you should use the TSB on the day of the race to look for any correlation. Depending on what people did the day before it may or may not make a significant difference, but could be important in some cases.

2) How did you determine each individual's FTP throughout their season? Since errors in TSS vary with the square of any error in TSS, it is important that their FTP be set as accurately as possible, or the PMC approach may fall apart due to GIGO.

3) Lastly, while it would mean a fair bit of additional number-crunching, I think it would be quite interesting* to analyze each rider's data using the classic impulse-response model, as well as the PMC approach. That would tell you just how much "watering down" Banister's approach weakens the ability to predict performance (power) based on TSS, versus the extent to which any lack of correlation is due to variability in the outcome measurement. Of course, to fit the classic impulse-response model to the data you have available would require assuming that the performance data are solid and can be normalized to some common scale, but you've already done that.

*To the point that it IMHO it would make the difference between a truly significant paper and a mildly interesting one.

 

[CoachFergie]

Thanks for your questions and comments Andy.

1) I noticed that the abstract refers to attempting to correlate CTL, ATL, or TSB on the previous day w/ performance on any given day. That would be appropriate for CTL and ATL, but not TSB as extracted using WKO+, since the latter is deliberately offset by one day into the future (the rationale being that you typically want to know your TSB just before you train or race, not afterwards). IOW, you should use the TSB on the day of the race to look for any correlation. Depending on what people did the day before it may or may not make a significant difference, but could be important in some cases.

Will adjust.

2) How did you determine each individual's FTP throughout their season? Since errors in TSS vary with the square of any error in TSS, it is important that their FTP be set as accurately as possible, or the PMC approach may fall apart due to GIGO.

Critical power. And a quick comparison of the deadly sins to see if there were any drastic errors in the FTP entered.

3) Lastly, while it would mean a fair bit of additional number-crunching, I think it would be quite interesting* to analyze each rider's data using the classic impulse-response model, as well as the PMC approach. That would tell you just how much "watering down" Banister's approach weakens the ability to predict performance (power) based on TSS, versus the extent to which any lack of correlation is due to variability in the outcome measurement. Of course, to fit the classic impulse-response model to the data you have available would require assuming that the performance data are solid and can be normalized to some common scale, but you've already done that.

Running out of time now to submit. Maybe for the PhD.

*To the point that it IMHO it would make the difference between a truly significant paper and a mildly interesting one.

One of the learning points from the process has been the realisation that I need a supervisor with a better understanding of the TrainingPeaks concepts. Also fair to say that after I had committed to this study a whole lot of new metrics came to light that I would rather have looked at (THANKS ANDY ).

Main thing I want to do is find some better measures for performance than MMP's. Or as suggested at WCSS use power meter data from track cycling where you would expect genuine MMP's from each race. One could possibly expect even in TT's at times the course, pacing, aerodynamic position, gradient etc could influence the power delivered relative to maximum power a rider could do for the duration. Ie on the awful Auckland track a rider held 400 watts for 5min in a National Pursuit Final where his max 5min power, from a hill effort was 500 watts.

 

[Retro Trev]

Main thing I want to do is find some better measures for performance than MMP's. Or as suggested at WCSS use power meter data from track cycling where you would expect genuine MMP's from each race. One could possibly expect even in TT's at times the course, pacing, aerodynamic position, gradient etc could influence the power delivered relative to maximum power a rider could do for the duration. Ie on the awful Auckland track a rider held 400 watts for 5min in a National Pursuit Final where his max 5min power, from a hill effort was 500 watts.

The problem is that so many things affect sustainable power output. As you say above, climbing v track, you also have, climbing v flat, road bike v TT bike, hot day v cold day, saddle height, outdoors v indoors, high inertia turbo v low inertia turbo. Most if not all riders can sustain a different power in all the above scenarios. Yet 300 watts gets the same TSS points regardless.
Then you also have the problem of fatigue. 300 watts for 5 minutes at the start of a session is far easier than 300 watts for 5 minutes after 5 hours, but same TSS score. An hour at FTP after a 5 day block of training is far harder than an hour at FTP when well rested and fresh, yet same TSS score. In fact if you can do an hour at FTP after 5 hard days in a row, your FTP. Is underestimated.

I can't see how power output in isolation can ever be a reliable measure of training stress.

 

[acoggan]

after I had committed to this study a whole lot of new metrics came to light that I would rather have looked at (THANKS ANDY ).

Jim Martin's favorite Linus Pauling quote seems appropriate here: "The best way to have a good idea is to have a lot of ideas."

 

[Alex Simmons/RST]

Jim Martin's favorite Linus Pauling quote seems appropriate here: "The best way to have a good idea is to have a lot of ideas."

Maybe it was the vitamin C.

 

[CoachFergie]

Why are power meters so expensive?

http://www.bikeradar.com/us/road/gear/article/angryasian-why-are-power-meters-so-expensive-41720/

 

[Tapeworm]

http://www.fitbie.com/get-fitter/track-cyclist-sarah-hammer-talks-training-technology

Sarah Hammer talks training.

 

[FrankDay]

Why are power meters so expensive?

http://www.bikeradar.com/us/road/gear/article/angryasian-why-are-power-meters-so-expensive-41720/

And, yet, so ineffective at actually helping people to improve.

 

[CoachFergie]

How a Powertap works. They appear to have skipped the part how it improves performance

http://www.bicycling.com/bikes-gear...power-meter-works?cid=socBG_20140804_29093666

 

[CoachFergie]

Interesting discussion on power output from this years Tour de France.

Cause for optimism for a clean win?

http://cyclingtips.com.au/2014/08/t...lysis-of-climbing-data-and-what-does-it-mean/

 

[sciguy]

Breaking the $500 barrier

It looks like competition on the lower end of the power meter price scale may be heating up even more. http://watteam.com/

Hugh

 

[CoachFergie]

Nice, that looks interesting Hugh.

More power based discussion from the Tour de France...

http://www.fietsica.be/Tour2014.pdf

 

[FrankDay]

Nice, that looks interesting Hugh.

More power based discussion from the Tour de France...

http://www.fietsica.be/Tour2014.pdf

As long as no precise data of efficiency and the relation of VO2CP to VO2max are available for each rider, the physiological plausibility of performance belongs to the realm of speculation.

Without actual data it is nothing but speculation. Nothing is really known (at least by us in the peanut gallery) about any of these riders. Even though we know that Armstrong doped, the fact we know he managed to improve his efficiency over the years helps explain his dominance over the other dopers.

 

[FrankDay]

Mr. (Dr.) Elapid. (and Fergie),

I think it is clear you are unhappy with my evidence that the cranks work as I claim. However, conversely, could you point me to your evidence that they don't work as I claim when used as we recommend?

While you may claim that the burden is on me to prove my claims I would say that the burden is really on you if you don't want to fall behind your competition should I be correct. It is all a matter of perspective.

 

[CoachFergie]

DC Rainmaker interviews the makers at Wattteam about the Power Beat.

http://www.dcrainmaker.com/2014/08/watteam-their-powerbeat.html

 

[coapman]

How a Powertap works. They appear to have skipped the part how it improves performance

[/QUOTE

Now we will have a proper PM, one that can demonstrate what is possible with torque application when you have the perfect TT pedalling power stroke.
Barry says:

August 5, 2014 at 08:20

" Paul, don’t fret, it’s coming! Launching at Interbike in Las Vegas on 10th September! You’re on our pre-order list so you will get information as soon as we release it. I see you’re close to the top of the list (thanks for your patience) which means that you will be among the first to have an opportunity to get your hands on a Zone power meter."

 

[sciguy]

[/QUOTE

Now we will have a proper PM, one that can demonstrate what is possible with torque application when you have the perfect TT pedalling power stroke.
Barry says:

August 5, 2014 at 08:20

" Paul, don’t fret, it’s coming! Launching at Interbike in Las Vegas on 10th September! You’re on our pre-order list so you will get information as soon as we release it. I see you’re close to the top of the list (thanks for your patience) which means that you will be among the first to have an opportunity to get your hands on a Zone power meter."[/QUOTE]

Noel,

It's exciting to see yet another player in the power meter market. That said, I wonder if your expectations of what they will show might be over generous. Right now it sounds as if they will yield information similar to the Garmin Vectors at best.

This from their FAQ.

"Will the system measure torque?

Yes. It measures forces and calculates torque continuously all the way round the crank revolution. You will see torque effectiveness and pedal smoothness if you have a display that shows them.

Will it measure forces all the way around a pedal rotation? Will it measure down force on the up stroke? Will it measure pull-up force?

The answer is yes to all these, although for simplicity our initial product will estimate pull-up forces rather than directly measure them. The system also continuously measures other details of how the cyclist is applying force to the pedal. "

It will be interesting to see what price point they will be placed at. The market is quickly becoming more competitive.

Hugh