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swuzzlebubble said:
Mr Ferg, thank you.
Alan has it wrong, normalised power is not a way of measuring variability of power.
- Mar 10, 2009
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CoachFergie said:
What he might be referring to is the ratio of NP to AP, sometimes referred to as the Variability Index (VI), which can indicate some level of variability in how the power was produced, however it's not always the case, as one can still have a highly variable power output yet still see a low-ish VI, which is why I prefer to simply refer to the ratio of NP to AP.
In any case, it's a pretty low hurdle to jump.
Keep in mind that something as simple as the recording head unit used and how it is set up can substantially affect AP and NP numbers, and have nothing to do with the power meter.
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You forgot to mention variations in tyre pressure and also kit or other weight.Alex Simmons/RST said:
Eg I left my lunch at home today so I didn't have as much in my backpack as usual. But then I guess on any normal day whether I have a big dump during the day or not could throw out data for my commute home
Basically I have my 'roadie profile' set up for the 'efficient case' - tyres up, good road, on the drops, at my fighting weight etc. This is close enough for me for most of my 'keener' rides and especially for any specific test/interval type stuff I might do. If I happen to drift away from that set-up on longer rides then I guess I may under-read for some sections. But I won't be beating any pb's due to the inverse case.
- Apr 21, 2009
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Alex has updated his awesome guide to selecting a power meter...
http://alex-cycle.blogspot.com.au/2013/08/which-power-meter.html
http://alex-cycle.blogspot.com.au/2013/08/which-power-meter.html
coapman said:
Noel,
It would appear that the Brim Brother's pedals do not provide the information that one would need to illustrate your unique pedaling method.
Hugh
- Apr 21, 2009
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sciguy said:
Beat me to it Hugh
2 years too late behind Look and Garmin.
Neither have changed the game. BB still not officially being produced.
Main issue is a lack of software.
The ability to test Noels theory has been around for 40 years. The ability to test if it actually improves performance is available to ANY power meter owner.
sciguy said:
" A post from the Brim Blog
News: Blowing our own trumpet
Thursday, February 10th, 2011, by Barry
We’ve decided that it’s time to correct our “publicity deficit” by spending some time explaining what we’re doing, and more importantly, what you will be able to do with our power meter. Most of you have heard the fanfare of various new announcements and promises for new power meters over the past 6 months. Some of them have involved very big names, have got lots of publicity, and have generated high expectations. Meanwhile we’ve been in our test labs and at our desks working hard on the technical and commercial development of our cleat-based power meter, and as we read all the claims for what other products will do we thought “ours does that – and more”. So it’s time we made some noise.
The Brim Brothers power meter measures not just power, but also cadence and a big chunk of other details about what’s going on with your feet and your pedals. It measures forces, pedal angles, crank angles and speed of rotation 100 times per second and uses this to calculate torque, power and cadence. The pods on the left and right shoes make these measurements and calculations independently and then communicate directly with each other over the ANT wireless system. One of the pods acts as the master by combining the values and transmitting them to an ANT+ compatible display. It’s all just plug-and-play, with nothing to be configured. The pods automatically decide which of them is the master, so there’s nothing to be configured for that.
If there’s only one pod then it will automatically double its own power measurement (as an estimate of the power on the other pedal) and send that to the ANT+ display. That means that if you use just one pod instead of a pair you will still have a usable power meter. By the way, the pods on each side are identical so it makes no difference which way round you use them. Each pod automatically works out whether it’s on the left or the right shoe. A major design goal in developing the power meter was that it should be easy to own and use, with absolute minimum configuration and calibration (and I’ll talk about calibration in another post soon) so we’ve come up with clever ways for the pods to work out things for themselves.
While the main purpose of the power meter is to send torque, power and cadence data to an ANT+ display, the detailed data stream is extremely interesting to look at. This gives us extra ways to see what’s going on as you pedal. The simplest is to look at how you apply force as the cranks rotate. Theoretically a rider should apply the maximum push-down force as the crank is half way through the down stroke, but we could see in our realtime graphs that our test rider was applying force very late and then continuing in an attempt to stretch the cranks at the bottom. Seems like he might benefit from adjusting his pedaling style a little, particularly by moving the application of force to slightly earlier in the pedal stroke.
Watching these graphs in realtime while cycling on an indoor trainer is quite intriguing. You can see immediately the effect of trying to, for example, apply force earlier in the down stroke. During these tests we had a discussion about the mental drivers and triggers that set the way you apply pedal force, and we went on to discuss how a rider uses the beat of music when training indoors and whether this could be used to improve pedaling efficiency. From observation it was apparent that our test rider pedals such that the music beat occurs just after the crank passes the horizontal position, so we did a short unscientific experiment where he consciously changed so that the beat occurred just before the crank passed the horizontal position. The effect was immediately obvious on the realtime graphs – the point of maximum force moved back in the crank rotation. We didn’t do any experiments to see if this resulted in any measurable improvement in efficiency (how would we quantify that anyway?) but I’m sure there are lots of knowledgeable people out there who will do these experiments as soon as we deliver the technology to them. "
Noel,
I just noticed that the blog entry you quoted was from 2011! It's interesting that the Brim Brothers no longer seem to be talking about any of this type usage even thought they did several years go.
Hugh
I just noticed that the blog entry you quoted was from 2011! It's interesting that the Brim Brothers no longer seem to be talking about any of this type usage even thought they did several years go.
Hugh
- Mar 10, 2009
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sciguy said:
More importantly, such data is not even required in order to demonstrate a benefit from a training intervention such as "technique changes", as if such a benefit existed it would result in more power and be readily measurable by any of the on-bike power meters that have been available commercially for over 25 years, or on ergometers that have been measuring cycling power output for over a century.
sciguy said:
I was searching for the original objectives of BrimBros and their PM, that was the best I could do. Maybe when they see and compare my techniques in action and notice how a simple switch in technique away from the natural styles can make a dramatic change to the pedalling graph between 11 and 5 o'c, they will realize that scientists have only scratched the surface of pedalling biomechanics and reconsider upgrading their PM. http://axiscranks.com/market-applications/bicycle-cranks/
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coapman said:
Yawn, old news. The ability to test this has been available for the last 40 years and no one has presented data to support your, or any other, claims of pedalling technique improvements from numerous attempts to do so.
You don't need force measuring pedals to show you can pedal in any fashion you want. But ANY power meter can be used to test if using a method and more importantly training and racing with that method has a significant influence on performance.
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DC Rainmakers 2014 Guide to Power Meters
http://www.dcrainmaker.com/2014/09/buyers-guide2014-edition.html
http://www.dcrainmaker.com/2014/09/buyers-guide2014-edition.html
I'm sure this could be asked before but, for those who work with Trainingpeaks, don't you think the IF isn't really accurate? I mean, I'm actually training in my Zone 2 doing endurance workouts, and I don't reach 0.75 IF, which is related to an endurance workout. For reaching it I must have at least 199 of NP, very close to my Zone 3.
So, for a minimum of 0.75 IF, do I have to train most of the time in Zone 3? I can't see clearly why if I train in Zone 2 (endurance), if I focus on the IF, it's less than 0.75, which is supposed to be for recuperation.
So, for a minimum of 0.75 IF, do I have to train most of the time in Zone 3? I can't see clearly why if I train in Zone 2 (endurance), if I focus on the IF, it's less than 0.75, which is supposed to be for recuperation.
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OfficialFlandrien said:I'm sure this could be asked before but, for those who work with Trainingpeaks, don't you think the IF isn't really accurate? I mean, I'm actually training in my Zone 2 doing endurance workouts, and I don't reach 0.75 IF, which is related to an endurance workout. For reaching it I must have at least 199 of NP, very close to my Zone 3.
So, for a minimum of 0.75 IF, do I have to train most of the time in Zone 3? I can't see clearly why if I train in Zone 2 (endurance), if I focus on the IF, it's less than 0.75, which is supposed to be for recuperation.
Is your FTP current? IF is based on this.
I use an IF of <.55 for recovery rides. .55-.75 for basic endurance, .75-.9 for Sweet Spot and .9 to 1.05 for threshold.
My FTP is actually 264, measured in a test last Monday. So, for a 0.75 IF, I must have an average NP of 198 minimum, what means training in Zone 3 part of the time.
I think you values are better and more realistic. I'll try them instead of what TPeaks says.
I think you values are better and more realistic. I'll try them instead of what TPeaks says
.
- Apr 21, 2009
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Personally feel this is reading waaay too much into the power meter file. Dude was on good form, had team support and took a chance that paid off. 50m longer and we may have been all talking about Gerrans winning!
http://blog.quarq.com/post/98896037596/kwiatkowskis-quarq-file-reveals-strategy-audacity
http://blog.quarq.com/post/98896037596/kwiatkowskis-quarq-file-reveals-strategy-audacity
- Mar 13, 2009
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the Pole sat up.CoachFergie said:
Effectively, it became a timetrial over the last 4 kms. And Kwiatk is a great timetrialler and pursuiter. I think he held both the jnr individual track pursit, AND the jnr road timetrial.
And like a young Thor Hushovd, he is always up there in those decimated fields on selective stages that are not tradition cavendish kippel mcewen bunch kicks. Kwiatk is always a top 10 on those.
That said, a sprint starting from a slower 5 man finish, around about 48kmph starting speed, the lighter weight of Gerrans, and Gerrans has got quite a punch in those sprints, Gerro just is not a big field sprinter where they need to expend 1000 watts in the preparation for the sprint and "jump" at around 60kmp. But if they have to jump from a rolling speed, Gerro can mix it. Dan Martin cant mix it like Gerro can. And in Gerro's favour, when alot of other riders, they may be GC riders, have looked to lose weight with peptides and "supplements", Gerro has done the opposite and worked on his sprint and power for those selective finishes, and now he can take Valverde mano a mano. The only guy Gerro would have trouble with is the Slovenian Sagan.
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blackcat said:
That can be measured and when people learn to understand it I expect we will see it added to most cycle computers (W'bal or FRCbal).
However I doubt even at a Pro level we will see too many, except Froome, riding like robots to the numbers.
More likely, people using the data to train their RPE or as Dr Lex Mauger suggested, at WCSS in Leeds, their pain threshold.
- Mar 18, 2009
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OfficialFlandrien said:I'm sure this could be asked before but, for those who work with Trainingpeaks, don't you think the IF isn't really accurate? I mean, I'm actually training in my Zone 2 doing endurance workouts, and I don't reach 0.75 IF, which is related to an endurance workout. For reaching it I must have at least 199 of NP, very close to my Zone 3.
So, for a minimum of 0.75 IF, do I have to train most of the time in Zone 3? I can't see clearly why if I train in Zone 2 (endurance), if I focus on the IF, it's less than 0.75, which is supposed to be for recuperation.
The training levels are based on average power expressed as a percentage of functional threshold power.
Intensity factor is based on normalized power expressed as a decimal fraction of functional threshold power.
By definition, training at level 2 would therefore mean riding at average power that is 56-75% of your FTP, which would usually result in an IF of 0.75-0.85.
Things are set up this way because the training levels pre-date the development of normalized power.
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