Froome's SRM data on Ventoux

[bigcog]

Re: Re:

Vayer and Salle are full of shyte when it comes to the numbers according to this:
http://cyclistsinternational.com/reports-of-froome-doping-wrong-in-so-many-ways/

Did the author only read doping accusations?

Any idiot could see that Froome was struggling against Quintana’s attacks in the final mountain stages of the Tour and used the help of his lieutenants Wout Poels and Richie Porte.

Coz any idiot would have read Froome was riding with some chest infection the last week or so.

The whole article is stupid -- especially when it delves into a comparison with football.

I notice you don't actually critique any of calculations made, made a by a different scientist. Weak.

 

[Dear Wiggo]

Re:

Then why is it when these models are actually put through some scientific rigour to assess their performance versus verified accurate meters do we find they are in general accurate, but lack precision? Like an SD of 10%, and 6% when windy climbs are removed.

http://www.fredericgrappe.com/wp-content/uploads/2015/01/Millet.pdf

People are over confident in the precision of these climbing power estimates.

To conclude, when a relatively large group of well-trained cyclists ride uphill, the average PO for the group can be estimated with an acceptable level of accuracy (<0.25% error). However, this margin of error increases to ~1% during windy conditions, and, more important, in some cyclists the error between Pmes and Pest was greater than 6%.

 

[Dear Wiggo]

And I don't even want to go into the history of "Lance's data looks clean" Grappe.

 

[Alex Simmons/RST]

Re:

And I don't even want to go into the history of "Lance's data looks clean" Grappe.

I don't see how that's relevant (the data in this study stands on it's own merit), but in any case, it's also the same person analysing Pinot's data over the years.
http://www.fredericgrappe.com/wp-content/uploads/2015/03/pinot-ppr.pdf

 

[Alex Simmons/RST]

Re: Re:

To conclude, when a relatively large group of well-trained cyclists ride uphill, the average PO for the group can be estimated with an acceptable level of accuracy (<0.25% error). However, this margin of error increases to ~1% during windy conditions, and, more important, in some cyclists the error between Pmes and Pest was greater than 6%.

I think you missed a bit.

The mean estimated values are close to the PO values measure by power meters, but the random error is between ±6% and ±10%. This finding calls into question the validity of releasing individual values without also providing the range of random errors, but it does allow for the comparison of group values obtained from a large number of observation points.

+/- 10% is for all model v measured comparisons, and +/- 6% is when they removed the data from windier days.

and this bit from the same paragrapgh you quoted from:

Those interested in better understanding hill-climbing PO need to recognize the many limitations associated with estimating uphill-cycling PO during important competitions such as the Tour de France.

 

[Texeng]

I believe BikeRadar did a test of about 4 different ways of measuring power and Stages were about as accurate as the rest of the brand leaders. Here are a couple of links https://www.youtube.com/watch?v=Xm6fxICaA_Q and https://www.youtube.com/watch?v=0yVFegrQEhk.

 

[Alex Simmons/RST]

Re:

I believe BikeRadar did a test of about 4 different ways of measuring power and Stages were about as accurate as the rest of the brand leaders. Here are a couple of links https://www.youtube.com/watch?v=Xm6fxICaA_Q and https://www.youtube.com/watch?v=0yVFegrQEhk.

The data released by Sky was not from a dual sided Stages, as was used in that video comparison.

 

[biker jk]

Re: Re:

It cannot be infinitely variable. Again, what's the range of error?

For a Stages with an aggressive Osym, assuming the meter itself is perfect and no user error, then anywhere from under reporting by 4% to over reporting by 10% would not surprise me in the slightest.

So why would you use this set up as a training aid?

 

[Alex Simmons/RST]

Re: Re:

It cannot be infinitely variable. Again, what's the range of error?

For a Stages with an aggressive Osym, assuming the meter itself is perfect and no user error, then anywhere from under reporting by 4% to over reporting by 10% would not surprise me in the slightest.

So why would you use this set up as a training aid?

Well for a start, I wouldn't. But then I'm not a pro that
(a) prefers to use such chainrings, and
(b) is paid by a power meter sponsor to use their power meter.

The fact that the data has limitations for some purposes doesn't make it completely useless. e.g. general guidance on effort while riding is a pretty low-fi application of power meter data. But for, say, precision assessment of power-duration models, well it'd be much less useful.

 

[Texeng]

Re: Re:

I believe BikeRadar did a test of about 4 different ways of measuring power and Stages were about as accurate as the rest of the brand leaders. Here are a couple of links https://www.youtube.com/watch?v=Xm6fxICaA_Q and https://www.youtube.com/watch?v=0yVFegrQEhk.

The data released by Sky was not from a dual sided Stages, as was used in that video comparison.

Maybe you watched a different video to the one I linked, which clearly shows a single sided Stages on Froomes bike at this year's TdF and the other video shows BikeRadar testing a Single sided Stages against SRM, Garmin etc. What made you think it was dual sided?

 

[Alex Simmons/RST]

Re: Re:

I believe BikeRadar did a test of about 4 different ways of measuring power and Stages were about as accurate as the rest of the brand leaders. Here are a couple of links https://www.youtube.com/watch?v=Xm6fxICaA_Q and https://www.youtube.com/watch?v=0yVFegrQEhk.

The data released by Sky was not from a dual sided Stages, as was used in that video comparison.

Maybe you watched a different video to the one I linked, which clearly shows a single sided Stages on Froomes bike at this year's TdF and the other video shows BikeRadar testing a Single sided Stages against SRM, Garmin etc. What made you think it was dual sided?

Ah, you're right, my bad. The first video shows the prototype dual sided Stages, hence my confusion.

In any case, the use of singled sided meter from one rider doesn't tell us much.

 

[Alex Simmons/RST]

As an aside, vetooo said he'd share with me his comparison data on model vs with Gesink's Pioneer meter, so can do some plots similar to the data from that science study linked earlier.

 

[danielovichdk2]

I did a session yesterday.
2x12km.
I ride with vectors, freshly calibrated.

First round I did in 19.52 and did 268 watts. My Garmin 510 measured it to 11.9km.
Second round I did in 20.42 and did 273 watts. My Garmin 510 measured it to 12.0km.

I pushed more watts on the second round put it took me 50 seconds to go around.

Yes, it can happen!

 

[Supimilian]

I did a session yesterday.
2x12km.
I ride with vectors, freshly calibrated.

First round I did in 19.52 and did 268 watts. My Garmin 510 measured it to 11.9km.
Second round I did in 20.42 and did 273 watts. My Garmin 510 measured it to 12.0km.

I pushed more watts on the second round put it took me 50 seconds to go around.

Yes, it can happen!

Can easily happen. And does all the time.
You just managed to keep the effort more steady the fist time, no?

 

[thehog]

Any updates on the Froome study? I thought I was being released in March? It's now May. Will it ever see the light of day?

 

[budegan]

Just how many inquiries does Brailsford have outstanding at the moment? Anyone know?

 

[SeriousSam]

Just how many inquiries does Brailsford have outstanding at the moment? Anyone know?

Team Sky are currently looking into the number of pending inquiries. Stay tuned for further updates as this inquiry proceeds.

 

[thehog]

Just how many inquiries does Brailsford have outstanding at the moment? Anyone know?

Team Sky are currently looking into the number of pending inquiries. Stay tuned for further updates as this inquiry proceeds.

From March 10th:

Jeroen Swart ‏@JeroenSwart
Those getting impatient on social media platforms regarding the peer reviewed manuscript of @chrisfroome test data. Relax, it's on track.

Jeroen Swart ‏@JeroenSwart
There are definitely some interesting and novel findings which I'm sure will provide a lot of interesting debate. @chrisfroome @GSK_HPL

Relax dudes, it's like totally coming by 2023, like chill out hommies

 

[WillemS]

Delays in publication of articles in peer reviewed journals happen; two months is nothing.

 

[budegan]

Okay, how about the data leak? Sorry "hacking".

 

[thehog]

Re:

Delays in publication of articles in peer reviewed journals happen; two months is nothing.

They said the same of the Henao study... it never came. Over two years we waited, Sir Dave said it was coming...

Will we ever see the Froome study this year? Next?

 

[Jeroen Swart]

Re: Re:

Delays in publication of articles in peer reviewed journals happen; two months is nothing.

They said the same of the Henao study... it never came. Over two years we waited, Sir Dave said it was coming...

Will we ever see the Froome study this year? Next?

Hog,

It has been submitted to very high impact journal.

We received a response from the editor with the reviewer comments exactly 1 week ago.

We are currently addressing the reviewers comments and will resubmit the revised manuscript before the end of June.

We hope and anticipate that the review process will then be completed.

These things do take time.

Thanks for the patience.

Jeroen

 

[sniper]

Jeroen, thanks for the update.
Will the article be only on the 2015 data or will it also analyze the 2007 data?

 

[thehog]

Re: Re:

Delays in publication of articles in peer reviewed journals happen; two months is nothing.

They said the same of the Henao study... it never came. Over two years we waited, Sir Dave said it was coming...

Will we ever see the Froome study this year? Next?

Hog,

It has been submitted to very high impact journal.

We received a response from the editor with the reviewer comments exactly 1 week ago.

We are currently addressing the reviewers comments and will resubmit the revised manuscript before the end of June.

We hope and anticipate that the review process will then be completed.

These things do take time.

Thanks for the patience.

Jeroen

They do take time when its a "high impact journal", whatever that means!? National Enquirer perhaps (I jest).

Regardless, lets wait and see what comes in June.... or July, August, September. Looking forward to the 2007 data and how its presented (not from those faxes).

Cheers.

 

[misshoggie]

The impact factor (IF) of an academic journal is a measure reflecting the yearly average number of citations to recent articles published in that journal. It is frequently used as a proxy for the relative importance of a journal within its field, with journals with higher impact factors deemed to be more important than those with lower ones.