New Power meters for team Sky

Macaloon

Crack crank action. All I'm saying.

frenchfighter

Ha yeah I remember that anecdote DD. Dig deep or go home eh.

You get out with Rick today? So this new job means you will be cycling around London?

Ben6899

Rick Chasey wrote:

Have you not seen the picture of Frenchie's thighs, opqs shorts and white shoes??

... and the grey - formerly-white - socks. Yeh, seen that.

above_the_cows

Someone needs to tell Richie about the new power metres.

nic_77

amaferanga wrote:

nic_77 wrote:

amaferanga wrote:

Whatever Sky are up to, don't take that to mean Stages works. If you're lucky you'll get ok data some of the time, but you'll never know when your L/R pedalling symmetry changes and introduces an additional error of several percent.

Would you be willing to estimate said percentage over say an hour TT effort? And how this would compare to the +/-error advertised for all PMs.

P.S. I'm definitely not defending my buying decision, I am genuinely interested in your thoughts (despite your condescending tone). I am more than willing to accept the compromise as the ease at which I can swap bikes far outweighs the absolute accuracy of the device.

Well I can only speak for myself, but when doing threshold intervals on the turbo and on the road I see 50/50 L/R balance, 49/51, 48/52. That's actually not too extreme - many people are much more asymmetric (and things are more variable for me for more variable efforts). Even this asymmetry introduces an additional 4% variability on top of other uncertainties. So at a modest 300W, that means a real 300W could reported as only 288W by Stages (+/- any other errors so maybe even as low as 282W). Anyone taking training with power remotely seriously should agree that that's just unacceptable - you could probably do just as well with RPE.

For the pro peloton things are obviously worse - that 4% error from a slight pedalling asymmetry at the typical FTP of a pro is getting on for 20W. I don't for a second believe that a team with the scientific approach of Sky would accept that for training.

I appreciate your response and if nothing else I agree that it seems odd for any pro team to take onboard unproven technology (especially a team like Sky for which accurate data is critical).

I would argue a couple of points - 1) any +/-2% error is capable of producing a 4% swing when comparing two data sets. 2) pedalling efficiency is an interesting area as it hasn't been studied in great detail, however I would expect efficiency to degrade in a comparable manner when riding repeats (which I might want to compare - thus negating the effect of this error).

That said, I'm personally pretty surprised that Stages have settled on the x2 algorithm to calculate total power. With known crank position and velocity (via their accelerometers) I reckon they could derive something more accurate to take account of left / right variation and apply it to measured left crank power.

Stages do have an advantage over all but the latest models of other conventional PMs in that their hardware includes a temperature sensor and can take care of temperature variation on the strain gauge measurements (temperature variation can be a pretty factor on a long climb with a big altitude gain).

rick_chasey

frenchfighter wrote:

Ha yeah I remember that anecdote DD. Dig deep or go home eh.

You get out with Rick today? So this new job means you will be cycling around London?

No. Rick bailed.

ddraver

Ben6899 wrote:

Rick Chasey wrote:

Have you not seen the picture of Frenchie's thighs, opqs shorts and white shoes??

... and the grey - formerly-white - socks. Yeh, seen that.

Yep - Cyclo-commuting starts tomorrow, fixie on Ride to Work Scheme pretty much locked in

Rick -

ocdupalais

nic_77 & amaferanga -
I'd have thought the ability to measure the power outputs of both legs throughout the pedal stroke was one of the most important features?

My suspicion is that mastery of the science/dark art of the pedal stroke is the source of great potential performance gains for any cyclist... I'd be intrigued to know what resources the pro teams devote to this. Would not be at all surprised that this is an area of secrecy for some...

nic_77

OCDuPalais wrote:

nic_77 & amaferanga -
I'd have thought the ability to measure the power outputs of both legs throughout the pedal stroke was one of the most important features?

My suspicion is that mastery of the science/dark art of the pedal stroke is the source of great potential performance gains for any cyclist... I'd be intrigued to know what resources the pro teams devote to this. Would not be at all surprised that this is an area of secrecy for some...

Well yes. Of course there is one stunt that Stages could pull - stick one of their pods on the drive side crank arm too (clearances permitting). Stages already have the ability to measure torque effectiveness and power smoothness through the stroke... I wonder?

andyp

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

Macaloon

andyp wrote:

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

If they have novel technology, but lack resources, it can be a very good deal for partners prepared to take a risk.

Richmond Racer

Be interesting to see what they use in TDU. If Porte and Earle on Sunday are anything to go by, it'll be SRM business as usual out there

amaferanga

andyp wrote:

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

It's pretty clear why it's important - 2 x left leg power does not necessarily equal actual power (left + right). There was a very long discussion on the Wattage list about Stages some months back which would be worth reading if you don't get it.

whiteboytrash

amaferanga wrote:

andyp wrote:

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

It's pretty clear why it's important - 2 x left leg power does not necessarily equal actual power (left + right). There was a very long discussion on the Wattage list about Stages some months back which would be worth reading if you don't get it.

Years ago I was bike fitted and found that my right let producing more power than my left. The data was invaluable. It took months of stretching to correct the problem but without that datapoint it never would have and probably would have resulted in injuries (plural).

I returned to the fit studio over that time to see the imbalance improve. At that time there was no power meters showing that data on the actual road. That's why I like Vector so much. It may not be prime time now but has an excellent platform for improvement.

jscl

Above The Cows wrote:

Someone needs to tell Richie about the new power metres.

It's a head unit, it can collect data from non-SRM power meters.

displacedaussie

It looks like the pics of the Stages PM were from their first test. The chaps in Aus at the moment* are still using their SRMs (but presumably will switch to the Stages once they get back to Europe and _if_ Sky are happy with the data they're getting from them).






* rode behind Thomas, Stannard, Rowe and Deignan for 15 minutes the other day

Anonymous

displacedaussie wrote:

It looks like the pics of the Stages PM were from their first test. The chaps in Aus at the moment* are still using their SRMs (but presumably will switch to the Stages once they get back to Europe and _if_ Sky are happy with the data they're getting from them).






* rode behind Thomas, Stannard, Rowe and Deignan for 15 minutes the other day

Last year the riders who did the TDU didn't get their new bikes until they were back in Europe because they didn't want too ship them out to Aus. I think that is part of the reason they are on SRM there.

Plus that will have been Portes own training bike, I imagine his spare bike was going on the Greenedge car, like Cav at the Brits this year (but with Sky.)

ocdupalais

amaferanga wrote:

andyp wrote:

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

It's pretty clear why it's important - 2 x left leg power does not necessarily equal actual power (left + right). There was a very long discussion on the Wattage list about Stages some months back which would be worth reading if you don't get it.

My back-of-fag-packet grasp of maths tells me that the implication of a leg imbalance is this: if, for example, you've spent countless hours training to be a competitive cyclist and you still have left/right functional power of say 48%-52%, that left leg is generating only 92.3% of the right (48 divided by 0.52), which means you are only generating 96.15% of your total capacity at that point in time. For an elite rider at Team Sky - to pick a team off the top off of the page - 3~5% is quite a chunk to be missing.

Ben6899

OCDuPalais wrote:

amaferanga wrote:

andyp wrote:

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

It's pretty clear why it's important - 2 x left leg power does not necessarily equal actual power (left + right). There was a very long discussion on the Wattage list about Stages some months back which would be worth reading if you don't get it.

My back-of-fag-packet grasp of maths tells me that the implication of a leg imbalance is this: if, for example, you've spent countless hours training to be a competitive cyclist and you still have left/right functional power of say 48%-52%, that left leg is generating only 92.3% of the right (48 divided by 0.52), which means you are only generating 96.15% of your total capacity at that point in time. For an elite rider at Team Sky - to pick a team off the top off of the page - 3~5% is quite a chunk to be missing.

But the right leg is producing 108% of the left. If the rider is balls out, then he's producing 100% of his "total power", regardless of what the meter is telling him.

mike6

Ben6899 wrote:

OCDuPalais wrote:

amaferanga wrote:

andyp wrote:

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

It's pretty clear why it's important - 2 x left leg power does not necessarily equal actual power (left + right). There was a very long discussion on the Wattage list about Stages some months back which would be worth reading if you don't get it.

My back-of-fag-packet grasp of maths tells me that the implication of a leg imbalance is this: if, for example, you've spent countless hours training to be a competitive cyclist and you still have left/right functional power of say 48%-52%, that left leg is generating only 92.3% of the right (48 divided by 0.52), which means you are only generating 96.15% of your total capacity at that point in time. For an elite rider at Team Sky - to pick a team off the top off of the page - 3~5% is quite a chunk to be missing.

But the right leg is producing 108% of the left. If the rider is balls out, then he's producing 100% of his "total power", regardless of what the meter is telling him.

Not Quite. The more muscles you recruit, within reason, in an activity the more powerful or more efficient you will be. Try pedaling one legged for a while and see how you get on.

Ben6899

mike6 wrote:

Ben6899 wrote:

OCDuPalais wrote:

amaferanga wrote:

andyp wrote:

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

It's pretty clear why it's important - 2 x left leg power does not necessarily equal actual power (left + right). There was a very long discussion on the Wattage list about Stages some months back which would be worth reading if you don't get it.

My back-of-fag-packet grasp of maths tells me that the implication of a leg imbalance is this: if, for example, you've spent countless hours training to be a competitive cyclist and you still have left/right functional power of say 48%-52%, that left leg is generating only 92.3% of the right (48 divided by 0.52), which means you are only generating 96.15% of your total capacity at that point in time. For an elite rider at Team Sky - to pick a team off the top off of the page - 3~5% is quite a chunk to be missing.

But the right leg is producing 108% of the left. If the rider is balls out, then he's producing 100% of his "total power", regardless of what the meter is telling him.

Not Quite. The more muscles you recruit, within reason, in an activity the more powerful or more efficient you will be. Try pedaling one legged for a while and see how you get on.

I totally agree.

BUT, you're only ever producing maximum 100%. AND whatever the meter says - due to inaccuracies - the facts are still the facts. I read OCDuPalais' post as if it was saying the meter can cause the rider to produce less power... which is clearly wrong... it can cause a misinterpretation, but there isn't a direct link.

Anyway, I think we're into semantics now and I promised myself I wouldn't contribute to this one.

ocdupalais

Ben6899 wrote:

mike6 wrote:

Ben6899 wrote:

OCDuPalais wrote:

amaferanga wrote:

andyp wrote:

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

It's pretty clear why it's important - 2 x left leg power does not necessarily equal actual power (left + right). There was a very long discussion on the Wattage list about Stages some months back which would be worth reading if you don't get it.

My back-of-fag-packet grasp of maths tells me that the implication of a leg imbalance is this: if, for example, you've spent countless hours training to be a competitive cyclist and you still have left/right functional power of say 48%-52%, that left leg is generating only 92.3% of the right (48 divided by 0.52), which means you are only generating 96.15% of your total capacity at that point in time. For an elite rider at Team Sky - to pick a team off the top off of the page - 3~5% is quite a chunk to be missing.

But the right leg is producing 108% of the left. If the rider is balls out, then he's producing 100% of his "total power", regardless of what the meter is telling him.

Not Quite. The more muscles you recruit, within reason, in an activity the more powerful or more efficient you will be. Try pedaling one legged for a while and see how you get on.

I totally agree.

BUT, you're only ever producing maximum 100%. AND whatever the meter says - due to inaccuracies - the facts are still the facts. I read OCDuPalais' post as if it was saying the meter can cause the rider to produce less power... which is clearly wrong... it can cause a misinterpretation, but there isn't a direct link.

Anyway, I think we're into semantics now and I promised myself I wouldn't contribute to this one.

My point was that if one leg produces more power relative to the other, then there is a very obvious "inefficiency in the system" (i.e. The weaker leg) - And were I a coach I would be addressing that.
If that discrepancy is causing as much as a few percent reduction in total power, then that equates to quite a significant performance disadvantage - especially the more elite your standard.
If the stronger leg can generate 800W maximum, I know that in theory the other one should potentially be able to do the same.
Not sure how you read my earlier post as saying "the meter can cause the rider to produce less power" Ben? Certainly didn't intend that.

slowbike

Isn't there two issues here ...

1) Training - a coach and rider will need to know the left/right balance in order to achieve optimal training.
2) Racing/Riding - to a set power level - doesn't matter if left/right is imbalanced so long as they are uniformly imbalanced. So when the DS or coach says "ride up that mountain at 450w" then that's what you do - doesn't matter if it's one legged or both. It's just at a reported 450w.

1) I would think that during training the coaches will have the riders in the lab to do their physical testing and then out on the road to work on the results.
2) During a training ride or race they can't all ride to an arbitrary power level - it'll have to be the leadout that rides to his defined level and the others follow his pace - they're following in his slipstream so they'll be using less power anyway.
I appreciate that they'll ride to a predetermined pace, especially up hills, but even there they won't be riding to matched power outputs - so how do they know what to do? Do they have pre-agreed levels - so RP's uphill pace1 may be 450w, pace2 = 500w and pace3=550w ? CF's may be pace1 = 430w, p2=480w and p3=520w ? Each rider having their own individual wattage levels - eitherwhich way, the left/right balance in that situation is less or unimportant as the rider will be riding to the set individual overall level and riding "normally" rather than trying to train one leg to produce more power to match the other.

I am surprised that TS would consider stages though as I had it down as a leisure rider toy rather than a pro tool ...

Ben6899

OCDuPalais wrote:

Ben6899 wrote:

mike6 wrote:

Ben6899 wrote:

OCDuPalais wrote:

amaferanga wrote:

andyp wrote:

Who knows, maybe Sky and Stages have agreed to work together to improve the product and satisfy the nerds who insist that measuring power on both cranks is important, even though they struggle to articulate why?

Strangers things have happened.

It's pretty clear why it's important - 2 x left leg power does not necessarily equal actual power (left + right). There was a very long discussion on the Wattage list about Stages some months back which would be worth reading if you don't get it.

My back-of-fag-packet grasp of maths tells me that the implication of a leg imbalance is this: if, for example, you've spent countless hours training to be a competitive cyclist and you still have left/right functional power of say 48%-52%, that left leg is generating only 92.3% of the right (48 divided by 0.52), which means you are only generating 96.15% of your total capacity at that point in time. For an elite rider at Team Sky - to pick a team off the top off of the page - 3~5% is quite a chunk to be missing.

But the right leg is producing 108% of the left. If the rider is balls out, then he's producing 100% of his "total power", regardless of what the meter is telling him.

Not Quite. The more muscles you recruit, within reason, in an activity the more powerful or more efficient you will be. Try pedaling one legged for a while and see how you get on.

I totally agree.

BUT, you're only ever producing maximum 100%. AND whatever the meter says - due to inaccuracies - the facts are still the facts. I read OCDuPalais' post as if it was saying the meter can cause the rider to produce less power... which is clearly wrong... it can cause a misinterpretation, but there isn't a direct link.

Anyway, I think we're into semantics now and I promised myself I wouldn't contribute to this one.

My point was that if one leg produces more power relative to the other, then there is a very obvious "inefficiency in the system" (i.e. The weaker leg) - And were I a coach I would be addressing that.
If that discrepancy is causing as much as a few percent reduction in potential total power, then that equates to quite a significant performance disadvantage - especially the more elite your standard.
If the stronger leg can generate 800W maximum, I know that in theory the other one should potentially be able to do the same.
Not sure how you read my earlier post as saying "the meter can cause the rider to produce less power" Ben? Certainly didn't intend that.

See my bold addition. Until the inefficiency is addressed, then the power generated is the actual total.

ocdupalais

Not disputing that.
And how do you address an inefficiency if you can't measure it (my original point)?

If you are training to improve your performance as a cyclist there's your starting point (you as you are in the present) and an objective (you as you would like to be in the future).
If your current total power is being undermined by a measurable inefficiency, then that is a clear indicator of what you could target to improve your total power.

Clearer?

Ben6899

OCDuPalais wrote:

Not disputing that.
And how do you address an inefficiency if you can't measure it (my original point)?

If you are training to improve your performance as a cyclist there's your starting point (you as you are in the present) and an objective (you as you would like to be in the future).
If your current total power is being undermined by a measurable inefficiency, then that is a clear indicator of what you could target to improve your total power.

Clearer?

All good. It was just semantics. And me being a pedant.

RichN95.

http://www.teamsky.com/article/0,27290, ... 30,00.html

amaferanga

I'm not aware of any evidence that shows that working on pedalling style to get 50/50 power balance will actually benefit performance. And while it may be possible to maintain a 50/50 balance on a controlled training ride, in the real world it'd seem much less likely to happen.

I don't agree with calling a L/R balance an inefficiency anyway, but again maybe that's just semantics.

ddraver

Amaf - if what you want to ride to is measured on a stages PM anyhow, would such an imbalance make a difference. I.e if BradRichie FroomeArd rode at 450W up the alpe on an SRM, but the stages read 440W for the exact same effort, becasue of an imbalance , would that make a difference?

alihisgreat

amaferanga wrote:

I'm not aware of any evidence that shows that working on pedalling style to get 50/50 power balance will actually benefit performance. And while it may be possible to maintain a 50/50 balance on a controlled training ride, in the real world it'd seem much less likely to happen.

I don't agree with calling a L/R balance an inefficiency anyway, but again maybe that's just semantics.

I'd assume an imbalance would cause further imbalances elsewhere in the system and contribute to injury problems?

If you're putting more power out through your right leg, then surely your core is working in unbalanced way when responding to the right leg as opposed to the left leg?