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The Powermeter Thread

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Sep 23, 2010
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sciguy said:
Just released in version 2.40

https://forums.garmin.com/showthread.php?76794-New-Power-Metrics-Torque-Effectiveness-(TE)-and-Pedal-Smoothness-(PS)


Torque Effectiveness = (((P+) + (P-))/(P+)) X 100


Pedal Smoothness = (Pavg/Pmax) X 100

I'm really interested in see the variation in riders, especially say Froome and the not so speedy pros.

Hugh
About time. If they incorporate this into a firmware update of my Edge 500 I should be able to give you my data. One thing surprises me though when they discussed pedal smoothness.
Based upon our testing, PS values typically fall in the 10%-40% range.
Pedal smoothness as they defined it is nothing more than the Racermate spinscan number divided in half. My experience has most riders with spinscan numbers in the 60-75 range. So, I would expect most to see a pedal smoothness number of 30-37.5, with the occasional rider getting into the 40+ area. How someone could ride with a PS of 10 would boggle my mind. I can ride with a spinscan on the trainer in the 90-95 area. It will be interesting to see how this translates into the road.

I think we will see substantial correlation between TE and PS because I suspect that those who are "just pushing harder" (low PS) will also be doing more negative on the upstroke so will have lower TE's. We will see.
 
May 13, 2011
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FrankDay said:
One thing surprises me though when they discussed pedal smoothness.Pedal smoothness as they defined it is nothing more than the Racermate spinscan number divided in half. My experience has most riders with spinscan numbers in the 60-75 range. So, I would expect most to see a pedal smoothness number of 30-37.5, with the occasional rider getting into the 40+ area.
.
Frank,

Perhaps I'm overtired tonight but I'm not sure where you're coming up with the divided in half part. Do you mean that they are calculating for each leg separately? Since this is a ratio doing one or both legs shouldn't influence things.......other than via an imbalance.

The SpinScan number is defined as: Average Torque divided by Maximum Torque multiplied by 100.

Hugh
 
sciguy said:
Just released in version 2.40

https://forums.garmin.com/showthread.php?76794-New-Power-Metrics-Torque-Effectiveness-(TE)-and-Pedal-Smoothness-(PS)


Torque Effectiveness = (((P+) + (P-))/(P+)) X 100


Pedal Smoothness = (Pavg/Pmax) X 100

I'm really interested in see the variation in riders, especially say Froome and the not so speedy pros.

Hugh
Poorly named metrics if you ask me.

The first implies a higher number = more effective, when that's a debatable starting premise, the latter suggests "smoothness" when it's just a ratio of peak to average torque, which as far as I can tell has little to do with "smoothness".
 
Sep 23, 2010
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sciguy said:
Frank,

Perhaps I'm overtired tonight but I'm not sure where you're coming up with the divided in half part. Do you mean that they are calculating for each leg separately? Since this is a ratio doing one or both legs shouldn't influence things.......other than via an imbalance.

The SpinScan number is defined as: Average Torque divided by Maximum Torque multiplied by 100.

Hugh
I was very confused when I first read this then I figured it out. Spinscan is the average torque divided by the maximum torque (of both cranks taken together). The Garmin number is the exact same formula but taken from each crank individually so the minimums are much smaller and, even, negative - a condition never seen by Spinscan. Assuming perfect balance, the maximum torque should be the same for the two formulas but the average torque for the Garmin formula is half the average torque for the Spinscan formula since it is only one crank so putting out half the power.

That explains why their expected high PS number is 40, approximately half of the highest spinscan number seen reasonably frequently. I think their 10% number would come about when the cyclist is soft pedaling at low power, because negative forces on the upstroke must be quite high (90%) compared to pushing forces to get such a number. This is the only condition I can imagine this happening.
 
May 13, 2011
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FrankDay said:
I was very confused when I first read this then I figured it out. Spinscan is the average torque divided by the maximum torque (of both cranks taken together). The Garmin number is the exact same formula but taken from each crank individually so the minimums are much smaller and, even, negative - a condition never seen by Spinscan. Assuming perfect balance, the maximum torque should be the same for the two formulas but the average torque for the Garmin formula is half the average torque for the Spinscan formula since it is only one crank so putting out half the power.
Aha, got it. That makes perfect sense. Max the same but average 1/2 as much.

Not sure if Garmin did the update for the 500 or just the newer models. Do you have a version that allows the two fields to be shown?
 
Sep 23, 2010
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sciguy said:
Aha, got it. That makes perfect sense. Max the same but average 1/2 as much.

Not sure if Garmin did the update for the 500 or just the newer models. Do you have a version that allows the two fields to be shown?
The little article says we should see the changes by the end of March. My 500 allows me to see left/right power from two meters so I suspect my 500 will allow me to see this change when they do an update. We shall see.

What bothers me is how lame the Garmin people are. They are afraid to commit to anything. Now that you will have this additional information what should you, our customer, do? We don't know and take no position. LOL. Anyhow, here is the real problem, as I see it. I expect that people will learn that it is better to have higher TE and PS (they should be related). But, Garmin is not giving them any data to tell them what they need to do to improve things. It is sad, all this capability and zero implementation. (OK, by the end of march it will be a little above zero implementation). Pioneer and iCranks (if they ever make it to market :) ) are the only two, so far, that seem to get it.
 
May 13, 2011
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FrankDay said:
The little article says we should see the changes by the end of March. My 500 allows me to see left/right power from two meters so I suspect my 500 will allow me to see this change when they do an update. We shall see.
.
Actually the post you are referring to relates to Garmin Connect an online Tracking, analysis and sharing site.

Garmin Connect
Support for viewing TE and PS values is currently being added to Garmin Connect and will be available before the end of March.

Update 2.40 is available right now but I'm not certain it works with the Garmin 500.
 
Sep 23, 2010
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sciguy said:
Actually the post you are referring to relates to Garmin Connect an online Tracking, analysis and sharing site.

Garmin Connect
Support for viewing TE and PS values is currently being added to Garmin Connect and will be available before the end of March.

Update 2.40 is available right now but I'm not certain it works with the Garmin 500.
We will see I suppose. Either way, it isn't like the information is particularly useful, IMHO, other than, perhaps, as an eye opener for the unbelievers.
 
May 13, 2011
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FrankDay said:
The little article says we should see the changes by the end of March. My 500 allows me to see left/right power from two meters so I suspect my 500 will allow me to see this change when they do an update. We shall see.

.
After a bit more investigation it's clear that the 2.40 update is for the Vector pedals so they are able to transmit the new metrics to the computer head. It would appear that unless the Icrank folks have or will update their cranks to transmit this information you're SOL even if the Garmin 500 will display the metric.

Hugh
 
Sep 23, 2010
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sciguy said:
After a bit more investigation it's clear that the 2.40 update is for the Vector pedals so they are able to transmit the new metrics to the computer head. It would appear that unless the Icrank folks have or will update their cranks to transmit this information you're SOL even if the Garmin 500 will display the metric.

Hugh
Garmin is, of course, interested in selling more Vector pedals but my understanding is the basic information being transmitted is the same because they are both using the ANT+ protocol. The iCranks currently work with the 500 giving me true left and right so I suspect that it will continue to work when they upgrade the firmware. We will see.
 
May 13, 2011
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FrankDay said:
Garmin is, of course, interested in selling more Vector pedals but my understanding is the basic information being transmitted is the same because they are both using the ANT+ protocol. The iCranks currently work with the 500 giving me true left and right so I suspect that it will continue to work when they upgrade the firmware. We will see.
Frank,

Go out and buy a 510 and be able to see these metrics today. You certainly can take it as a tax write off . I doubt Garmin with upgrade the 500 for these functions as it's old technology at this point.

Hugh
 
Sep 23, 2010
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sciguy said:
Frank,

Go out and buy a 510 and be able to see these metrics today. You certainly can take it as a tax write off . I doubt Garmin with upgrade the 500 for these functions as it's old technology at this point.

Hugh
I am not going to buy a 510 to just get this lame data. Soon (I hope) I will have a head unit that gives me torques around the entire circle, something I consider to be actually useful.
 
Aug 6, 2009
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sciguy said:
Perhaps I'm a bit confused? First your say:



and then when a much less expensive ($1850 vs $3145 MSRP for a Dura Ace model) and technologically more evolved unit comes out you're not happy?



So you're not happy that a much less expensive and arguably more technologically advanced unit is on the market?

Hugh
The second statement you quoted was meant sarcastically.
 
Sep 23, 2010
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I am considering developing my own power meter to integrate into the PowerCranks. I am in the brainstorming stage as I know what I would want in a PM and what I want that you can't get in the current crop (or anything coming down the line that I can see). Since I am in the brainstorming stage I thought I might ask others here what they might want in a PM that they can't get now to see what I might be missing. Just looking for ideas folks as to how to make this tool better/more useful. PM me if you have ideas/wants but are not interested in posting. Thanks
 
Mar 10, 2009
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FrankDay said:
I am considering developing my own power meter to integrate into the PowerCranks. I am in the brainstorming stage as I know what I would want in a PM and what I want that you can't get in the current crop (or anything coming down the line that I can see). Since I am in the brainstorming stage I thought I might ask others here what they might want in a PM that they can't get now to see what I might be missing. Just looking for ideas folks as to how to make this tool better/more useful. PM me if you have ideas/wants but are not interested in posting. Thanks

PE = T/F X 100.

Pedaling effectiveness = Torque / Sum of all pedal forces / 100. Sum of all forces includes tangential, non tangential and down force on rising pedal.
 
Apr 21, 2009
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Will be presenting my research at the World Congress of Cycling Science in Leeds in July...

Measures of training stress in cyclists do not usefully predict maximum mean power in competitions

H.A. Ferguson1, C.D. Paton2, W.G. Hopkins1

1Auckland Institute of Technology, Auckland, New Zealand; 2Eastern Institute of Technology, Napier, New Zealand.

Background
Many competitive cyclists use mobile ergometers to monitor power output during training and competition rides. A training-impulse model is then often used to combine a training-stress score from each ride into measures of "fitness" and "fatigue", the difference in which is interpreted as a measure of "freshness" that might predict competitive performance.

Purpose
To determine the effect of fitness, fatigue and freshness the day before cycling competitions on physiological indicators of performance in the competitions.

Methods
Twenty male and four female competitive cyclists (29 ± 9 y, 71 ± 7 kg, mean ± SD) provided recordings of their SRM or Quarq mobile ergometers for training rides, 55 time trials (16-40 km), and 447 mass-start road races over a 6- to 8-month period. TrainingPeaks software (version WKO+ 3) was used to synthesize fitness, fatigue and freshness scores on the day before each competition and to extract maximal mean power (MMP) for four durations (5 s, 60 s, 5 min, 20 min) from the competition ride. The within-cyclist relationship between each measure of training and each measure of performance was investigated by producing scatterplots of the deviations from each rider's mean training and mean performance measure for time trials and road races in single-day and multi-day competitions. Mixed modeling was used to quantify the relationship as the linear effect of a change of two within-cyclist standard deviations of the measure of training, assuming a smallest important change in performance of 1%.

Results
Individual typical variation in maximum mean power from competition to competition ranged from ±7.1% (5-min MMP) to ±14% (5-s MMP). Scatterplots were generally consistent with a random relationship between the indicators of performance in competitions and the measures of training the previous day, and all effects of training measures on performance measures were unclear.

Discussion
The uncertainty in the relationships between the measures of training and the measures of performance is due to the extremely poor reliability of the measures of maximum mean power. Contextual information about each competition ride might improve the reliability by helping to filter out or otherwise account for poorer performances. Alternatively other measures of performance from competitions are needed to determine whether fitness, fatigue and freshness usefully predict competition performance.

Conclusions
Maximum mean power in competitions is too unreliable to determine whether the measures of fitness, fatigue and freshness provided by mobile ergometers and TrainingPeaks software reflect readiness for competitions.
 
Sep 23, 2010
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CoachFergie said:
Will be presenting my research at the World Congress of Cycling Science in Leeds in July...

Measures of training stress in cyclists do not usefully predict maximum mean power in competitions

H.A. Ferguson1, C.D. Paton2, W.G. Hopkins1


Conclusions
Maximum mean power in competitions is too unreliable to determine whether the measures of fitness, fatigue and freshness provided by mobile ergometers and TrainingPeaks software reflect readiness for competitions.
So, are you saying your research came to the conclusion that all that PM data isn't very useful regarding competition?
 
FrankDay said:
So, are you saying your research came to the conclusion that all that PM data isn't very useful regarding competition?
That's a very long bow Frank.

I'd say that Fergie found the endurance cycling events used (time trials and mass start road races) are unsuitable for assessing neuromuscular power and hence how NMP might vary with training stress indicators.

IOW perhaps a different form of input (e.g. one that includes a more reliable means to establish NMP) is required to assess what relationship might exist.
 
Apr 21, 2009
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Alex Simmons/RST said:
That's a very long bow Frank.

I'd say that Fergie found the endurance cycling events used (time trials and mass start road races) are unsuitable for assessing neuromuscular power and hence how NMP might vary with training stress indicators.

IOW perhaps a different form of input (e.g. one that includes a more reliable means to establish NMP) is required to assess what relationship might exist.
Ha ha isn't Frank funny.

Yes, was always going to be a stretch using max mean powers as a measure of performance. But even within a group of elite endurance cyclists competing in different events round the World and having different roles and abilities within a race the stats indicate we need better performance metrics to assess the usefulness of the PMC.

I headed in this direction in August and fair to say that Andy Coggan's webinars in November answered a lot of the questions I had hoped to answer with the study. So it's not breaking new ground but highlights many more questions to be answered. Fairly typical for a Masters project.

Still more stoked that I will be in Leeds for the start of the Tour!
 
Sep 23, 2010
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Alex Simmons/RST said:
That's a very long bow Frank.

I'd say that Fergie found the endurance cycling events used (time trials and mass start road races) are unsuitable for assessing neuromuscular power and hence how NMP might vary with training stress indicators.

IOW perhaps a different form of input (e.g. one that includes a more reliable means to establish NMP) is required to assess what relationship might exist.
OK. I guess one might ask why Fergie chose to study this if he didn't expect it to show a benefit but, surprise, it didn't. what kind of events might this information be useful do you predict? That having been said, could anyone point me to a single study that demonstrates a power meter provides an advantage for anything?
 

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