First power meter - guidance and feedback please
- Alex Simmons/RST
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Re: First power meter - guidance and feedback please
Postby Alex Simmons/RST » Sun Apr 01, 2018 9:18 am
As a ROT, energy expended in kcal = 1.05 - 1.15 x mechanical work done in kJ.
IOW if you take the kJ reading from your power meter, add 10% and call that Calories metabolised, you'll most likely be in the right range give or take 5%.
While there are differences, on average, in efficiency between untrained, recreational and trained cyclists, those differences are smaller than the individual variability of efficiency between riders at each level. IOW a recreational rider can still be more efficient than a trained cyclist.
That's because inherit biochemical factors, muscle fibre type mix and the duration and relative workload of effort are more influential on one's individual GME than various and often purported pedalling technique improvements - due to the fact that cycling is a motion performed without many degrees of freedom.
You can be more precise with metabolic energy demand from cycling if:
i. you know your GME via gas exchange analysis performed in a lab, and
ii. your cycling is mostly relatively steady state.
That said it is possible to determine VO2max (and hence GME) with reasonable accuracy using a good power-duration model if you have sufficient quality mean maximal power data across a decent range of duration (e.g. from 5s to 3600s). But this is relatively new and its application requires care in understanding limitations (usually a result of factors influencing the quality of data inputs and a wise choice of model).
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Re: First power meter - guidance and feedback please
Postby CKinnard » Sun Apr 01, 2018 11:57 am
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Re: First power meter - guidance and feedback please
Postby Arbuckle23 » Sun Apr 01, 2018 12:05 pm
I have plenty of gasCKinnard wrote:Gas exchange analysis
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Re: First power meter - guidance and feedback please
Postby Alex Simmons/RST » Sun Apr 01, 2018 12:48 pm
So?CKinnard wrote:Gas exchange analysis is confounded by diet composition, bodyfat %, fat burning adaptation, and insulin resistance.
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Re: First power meter - guidance and feedback please
Postby CKinnard » Mon Apr 02, 2018 12:26 pm
These are factors that effect GME calculation and result.Alex Simmons/RST wrote:So?CKinnard wrote:Gas exchange analysis is confounded by diet composition, bodyfat %, fat burning adaptation, and insulin resistance.
Pedaling technique has been too casually dismissed in its influence on GME. i.e the influence of cadence on climbing efficiency.
And more significant inputs to GME are a higher % of total blood flow (cardiac output) to key cycling muscles, and glycogen storage in same.
Experienced riders on average are likely to have an advantage in both.
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Re: First power meter - guidance and feedback please
Postby Alex Simmons/RST » Mon Apr 02, 2018 2:50 pm
Again, so what?CKinnard wrote:These are factors that effect GME calculation and result.Alex Simmons/RST wrote:So?CKinnard wrote:Gas exchange analysis is confounded by diet composition, bodyfat %, fat burning adaptation, and insulin resistance.
Pedaling technique has been too casually dismissed in its influence on GME. i.e the influence of cadence on climbing efficiency.
And more significant inputs to GME are a higher % of total blood flow (cardiac output) to key cycling muscles, and glycogen storage in same.
Experienced riders on average are likely to have an advantage in both.
In the context of this thread, i.e. guidance on using a power meter, it's hardly pertinent.
Yes, elite riders are, on average, a little bit more efficient than trained, recreational and untrained riders. So what?
The differences in efficiency between such rider levels is not actually all that much (~10% on average), and they pale when compared with the differences in sustainable power output for riders across the capability spectrum (which are of the order of ~300-400%). IOW differences in efficiency only account for a small proportion of the differences in physiological capability. And our ability to positively influence GME is rather limited because it is dominantly an inherited trait.
When testing efficiency there are typically controls wrt the relative intensity one tests at, and what pre-test controls are put in place, such as diet, fatigue, glycogen levels and so on. Yes efficiency varies with cadence and other factors affect it on an acute and chronic basis. Environmental conditions or hydration status for instance. Yawn. Tell us something new or useful in context of this thread.
Cadence is not "technique". It's just a measure of crank rotational velocity.
Indeed cadence is not something we can actually independently control, despite what one might believe.
What we can control is our level of effort (power output) and gear choice. Cadence is then an outcome of those choices and the resistance forces acting against us at the time.
As for technique being lightly dismissed, meh I just refer to the published science which demonstrates changing "technique" from that which develops naturally really doesn't do all that much.
In any case we don't typically pedal at cadences equated with the highest efficiency (we tend to pedal more quickly that that) since maximising efficiency isn't typically the objective of cycling (certainly not in any competitive or performance sense). What does matter (physiologically) is the ability to sustain power output over durations of relevance. Fortunately that's what a power meter tells us, and is what makes it really useful.
In any case, esoteric discussion of GME is not really of much value here.
Information about using the power meter in a productive manner is the topic.
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Re: First power meter - guidance and feedback please
Postby MichaelB » Mon Apr 02, 2018 3:40 pm
Anyway, even if I could work it out with a power meter, I wouldn't work it out.
Far beyond what this thread was all about anyway. BoT.
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Re: First power meter - guidance and feedback please
Postby Alex Simmons/RST » Tue Apr 03, 2018 7:07 am
Gross Mechanical Efficiency.MichaelB wrote:I dunno what GME is ?
It's the ratio of mechanical energy applied to the cranks of the bicycle to the total energy metabolised by our body.
Approximately 1/5th of the energy we metabolise ends up reaching the cranks. The vast majority of the balance is given off as waste heat.
That was my point. Focus on power as it's the integral of all the underlying processes and factors, and is what matters.MichaelB wrote: Anyway, even if I could work it out with a power meter, I wouldn't work it out.
Far beyond what this thread was all about anyway. BoT.
For those interested in using the power meter for keeping an eye on their energy balance (i.e. food calories in, exercise and base metabolism calories out), then just use the simple method I outlined earlier for estimating the energy demand while cycling.
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Re: First power meter - guidance and feedback please
Postby Arbuckle23 » Tue May 22, 2018 6:48 pm
Had problems with the first sensor, so Watteam sent me another. It too gave problems.
Getting dropouts all the time, readings all over the place, even on a trainer
Contacted Pushys and returned to them for a full refund.
Big Kudos's to Pushys, no problems in returning when I voiced my dissatisfaction with the product.
But the little taste of power now has me in.
Spent a little more on pedal based Favero Assioma.
Been using for a week with no problems, very happy. Solid as a rock.
Riding with/to power is such an eye opener. A lot more to learn, but will enjoy the learning.
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Re: First power meter - guidance and feedback please
Postby MichaelB » Tue May 22, 2018 9:51 pm
Presume single sided ?
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Re: First power meter - guidance and feedback please
Postby Arbuckle23 » Wed May 23, 2018 6:54 am
All the chat about single sided got to me, upgrading later would cost even more.
The good thing is that the pedals can fit my backup bike now. Different crankset types on each bike.
The interesting thing I have learnt about knowing both sides, is that I consistently seem to be 52/48 L/R. And slightly more again on the left when working harder.
Being right handed and useless with my left hand and foot I would have thought it should have gone the other way?
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Re: First power meter - guidance and feedback please
Postby MichaelB » Wed May 23, 2018 8:37 am
Get War Office approval ?Arbuckle23 wrote:I decided that I would blow the budget right out of the water and got dual sided .
..
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Re: First power meter - guidance and feedback please
Postby Arbuckle23 » Wed May 23, 2018 9:50 am
SshMichaelB wrote: Get War Office approval ?
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Re: First power meter - guidance and feedback please
Postby Alex Simmons/RST » Wed May 23, 2018 11:33 am
Power asymmetry is variable and often unrelated to what is our natural side.Arbuckle23 wrote:I decided that I would blow the budget right out of the water and got dual sided .
All the chat about single sided got to me, upgrading later would cost even more.
The good thing is that the pedals can fit my backup bike now. Different crankset types on each bike.
The interesting thing I have learnt about knowing both sides, is that I consistently seem to be 52/48 L/R. And slightly more again on the left when working harder.
Being right handed and useless with my left hand and foot I would have thought it should have gone the other way?
But to put it into context, there were times when I was measured as left side dominant while at an easy endurance power level which considering I'm a left below knee amputee may be a little surprising. As the power level went up, I evened up in my power balance.
One of the things with meters which measure each crank/pedal independently is you now actually have two power meters, each with potential error or bias in their readings. It's also twice as many things to go wrong
All good fun.
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Re: First power meter - guidance and feedback please
Postby Alex Simmons/RST » Wed May 23, 2018 11:35 am
Bummer. But what matters most is that the after sales support backed you up. That's the bit I worry about with the newer players. Perhaps less so early on but later when the weight of longer term financial viability begins to bite.Arbuckle23 wrote:At the risk of Alex telling me "I told you so" The Powerbeat has been sent back.
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Re: First power meter - guidance and feedback please
Postby MichaelB » Wed Nov 14, 2018 3:38 pm
It does however, do what I want it to do, so all is good in the world.
BUT, I've now bought a Gravel bike, and will use that a bit as well. So that I don't miss the data sets that I would get when I use the bike (the hrTSS is typically 25% lower than the TSS recorded for the same route (and times) when using a PM).
The bike is a Cannondale Slate and comes with their Si crankset. BikeBug have a 50% off sale on the Pioneer Cannondale Consumer Supplied Left Crank Power Meter for $399.
I know this isn't as accurate as other PM's etc, but compared to the similar options like Stages and 4iii, is this probably the best deal for this type of PM ?
TIA
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Re: First power meter - guidance and feedback please
Postby MichaelB » Thu Nov 15, 2018 8:22 am
Hi Michael
That is still the case.
Here's a pre install check list that gives the clearances you need:
We generally allow 2 to 3 business days for installation upon receipt of your cranks here:
3/595 Princes Highway
Tempe NSW 2044
AUSTRALIA
After ordering send them in along with a copy of the order and the completed check list.
It is a Pioneer requirement that it is installed and calibrated here.
Now, the colour & highlight of the last sentence is mine. What a CROCK !! And what annoys me even more is that it's not stated anywhere in the ad.
Oh, I can take it off myself, but can't put it on and link it to my computer. How dumb is that.
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Re: First power meter - guidance and feedback please
Postby madmacca » Thu Nov 15, 2018 1:53 pm
DCRainmaker's annual power meter guide has just come out at https://www.dcrainmaker.com/2018/11/pow ... -2018.html if you want to check his view of the market.MichaelB wrote:OK, I've now been using the PM (FSA Powerbox) for almost a year now, and am really happy with it, even though I don't use it as well as I could.
It does however, do what I want it to do, so all is good in the world.
BUT, I've now bought a Gravel bike, and will use that a bit as well. So that I don't miss the data sets that I would get when I use the bike (the hrTSS is typically 25% lower than the TSS recorded for the same route (and times) when using a PM).
The bike is a Cannondale Slate and comes with their Si crankset. BikeBug have a 50% off sale on the Pioneer Cannondale Consumer Supplied Left Crank Power Meter for $399.
I know this isn't as accurate as other PM's etc, but compared to the similar options like Stages and 4iii, is this probably the best deal for this type of PM ?
TIA
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Re: First power meter - guidance and feedback please
Postby MichaelB » Thu Nov 15, 2018 2:23 pm
Cheers for that.madmacca wrote:
DCRainmaker's annual power meter guide has just come out at https://www.dcrainmaker.com/2018/11/pow ... -2018.html if you want to check his view of the market.
The only key for me is the 50% off at Bike Bug. That's where the Pioneer comes in better, and for the Cannondale arms, Stages are exxy.
Update on the fitment stuff : Seems I can get it 'fitted' at the Adelaide store. Still a bit stoopid, but workable, especially for that price.
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Re: First power meter - guidance and feedback please
Postby macca33 » Fri Nov 16, 2018 12:58 am
MichaelB wrote:Duly sent off email clarifying the 'how', and got this reply ;
Hi Michael
That is still the case.
Here's a pre install check list that gives the clearances you need:
We generally allow 2 to 3 business days for installation upon receipt of your cranks here:
3/595 Princes Highway
Tempe NSW 2044
AUSTRALIA
After ordering send them in along with a copy of the order and the completed check list.
It is a Pioneer requirement that it is installed and calibrated here.
Now, the colour & highlight of the last sentence is mine. What a CROCK !! And what annoys me even more is that it's not stated anywhere in the ad.
Oh, I can take it off myself, but can't put it on and link it to my computer. How dumb is that.
I'm fairly sure that the 'installation' is the physical bonding of the PM sensor to the crankarm and I'm fairly sure that it has to be done to an exacting specification, which is why they need your crank arm sent to them.
cheers
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Re: First power meter - guidance and feedback please
Postby biker jk » Fri Nov 16, 2018 7:05 am
Exactly. That's what 4iiii requires as well with their factory install option. You send them your crank.macca33 wrote:MichaelB wrote:Duly sent off email clarifying the 'how', and got this reply ;
Hi Michael
That is still the case.
Here's a pre install check list that gives the clearances you need:
We generally allow 2 to 3 business days for installation upon receipt of your cranks here:
3/595 Princes Highway
Tempe NSW 2044
AUSTRALIA
After ordering send them in along with a copy of the order and the completed check list.
It is a Pioneer requirement that it is installed and calibrated here.
Now, the colour & highlight of the last sentence is mine. What a CROCK !! And what annoys me even more is that it's not stated anywhere in the ad.
Oh, I can take it off myself, but can't put it on and link it to my computer. How dumb is that.
I'm fairly sure that the 'installation' is the physical bonding of the PM sensor to the crankarm and I'm fairly sure that it has to be done to an exacting specification, which is why they need your crank arm sent to them.
cheers
- MichaelB
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- Location: Adelaide, South Australia
Re: First power meter - guidance and feedback please
Postby MichaelB » Fri Nov 16, 2018 7:40 am
Maybe didn’t have enough coffee yesterday.
Anyway, ordered, measurements taken (it’s a bit close, but should be fine) crank removed and ready to be sent off today.
Interesting that Pioneer also want the pedal centreline length as well.
Anyway, getting posted today
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