Powercal?... really???

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Re: Powercal?... really???

Postby twizzle » Fri May 24, 2013 10:24 pm

Xplora wrote:...

Edit: Hmmm HR got down to 42 and stayed around 45 while sitting in front of the TV :| :| :|


Bit unfit, are we? :P


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by BNA » Sat May 25, 2013 8:40 am

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Re: Powercal?... really???

Postby foo on patrol » Sat May 25, 2013 8:40 am

Xplora wrote:And I'm testing it out now. I am thinking that 3s power is a bit excitable for my liking, but we'll see. You get power info while typing :lol: Resting heart rate staring at the screen is under 50bpm? :shock: Do a ride tomorrow, see how we go hey?

Edit: Hmmm HR got down to 42 and stayed around 45 while sitting in front of the TV :| :| :|


Never had a heart rate that low, even when fit! :shock: Bloody show off. :lol:

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Re: Powercal?... really???

Postby Xplora » Sun May 26, 2013 9:55 pm

First ride on the shop bunch ride with it was reasonably interesting, I had it linked to 30 second power on the computer and that's just not enough responsiveness imo. Found the HR data more useful, however I need to do an FTP test first to have some idea of thresholds, plus you need 3 months of data to get a reasonably accurate peak power curve over the various time scales. Right now, just knowing LTHR would be a bonus, but it is somewhat hard to figure out what is "normal" as far as HR goes since my resting heart rate was in the 40s and I've traditionally thought it was around 65. A lot of this confusion is really "getting the data" and "using the data?!" which takes time and effort.
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Re: Powercal?... really???

Postby vander » Sun May 26, 2013 10:02 pm

What HR can you hold for an hour thats pretty much your LTHR. IMO powercal is a joke.
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Re: Powercal?... really???

Postby g-boaf » Mon May 27, 2013 1:45 pm

Not really, it's a better HRM than the standard Garmin premium one, but that's about all. The power info is laggy and prone to big spikes as well... 2000 watts? I'm not that powerful.
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Re: Powercal?... really???

Postby Trek_Arty » Mon May 27, 2013 3:46 pm

Some interesting graph comparisons in this review... Seems the data output isn't the greatest

http://www.bikeradar.com/gear/category/ ... 47026#null
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Re: Powercal?... really???

Postby Xplora » Mon May 27, 2013 4:47 pm

Yep, the BikeRadar was the only negative review I've found, and to be honest, it doesn't seem to accept the severe limitations of the device. It's supposed to be HRM on steriods as opposed to a neutered Powertap LOL
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Re: Powercal?... really???

Postby Xplora » Mon May 27, 2013 6:43 pm

vander wrote:What HR can you hold for an hour thats pretty much your LTHR. IMO powercal is a joke.

Testing for that isn't easy if you aren't doing 40km TTs ;)
As far as the tool being a joke, what could you possibly be basing that on? Every single experienced power meter user that has bothered to do the data and do a review on it seems to be very positive about it. If you can afford a SRM then good on you. Many of us cannot, and if you use it wisely then it has potential to be extremely valuable. I'm not expecting it to be useful for pacing 2 minute efforts but more for TSS values and decoupling, which are helpful for gauging your progress in periodisation. I'm nursing a bung knee from overdoing it.
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Re: Powercal?... really???

Postby vander » Mon May 27, 2013 7:32 pm

Xplora wrote:
vander wrote:What HR can you hold for an hour thats pretty much your LTHR. IMO powercal is a joke.

Testing for that isn't easy if you aren't doing 40km TTs ;)
As far as the tool being a joke, what could you possibly be basing that on? Every single experienced power meter user that has bothered to do the data and do a review on it seems to be very positive about it. If you can afford a SRM then good on you. Many of us cannot, and if you use it wisely then it has potential to be extremely valuable. I'm not expecting it to be useful for pacing 2 minute efforts but more for TSS values and decoupling, which are helpful for gauging your progress in periodisation. I'm nursing a bung knee from overdoing it.


Its a HR monitor. Its not a powermeter they are very different things, a HR monitor cannot (as this is) pretend to be a powermeter. Second hand wired powertaps are pretty cheap these days (probably not much more than the HR monitor). Jump on the trainer for an hour do an effort for an hour what can you hold for that long. Alternatively go to Calga next sunday ride the 43km TT.
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Re: Powercal?... really???

Postby twizzle » Tue May 28, 2013 9:20 am

Xplora wrote:As far as the tool being a joke, what could you possibly be basing that on?


I agree with Vander - there is only a slight relationship between HR and power, and only for longer efforts. Wired PT hub kits were under $750US before they discontinued them last year.
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Re: Powercal?... really???

Postby twizzle » Tue May 28, 2013 10:06 am

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Re: Powercal?... really???

Postby Xplora » Tue May 28, 2013 10:24 am

twizzle wrote:
Xplora wrote:As far as the tool being a joke, what could you possibly be basing that on?


I agree with Vander - there is only a slight relationship between HR and power, and only for longer efforts. Wired PT hub kits were under $750US before they discontinued them last year.

And you don't think CycleOps is able to demonstrate an effective algorithm for that relationship? Unfortunately, even experts will not have access to the same amounts of data as one of the biggest power meter companies in the world. This company stopped even bothering with a calibration procedure because it didn't add enough accuracy. The simple fact is that HR isn't the only measure, but change in HR. If you can't be bothered thinking harder about that, then there really isn't much point talking about the product. It's no different to arguing speed vs acceleration. They are completely different, despite being related. A HRM cannot measure change in HR, the PowerCal can. It spits out something that is reasonably accurate to power. If you feel the need to go out and spend 700-1500-3000 bucks getting more accuracy, that's awesome. I will not stop you. There are people out there who pooh poohed the Stages power meter because it only measured one leg. A genuine power meter STILL isn't good enough if you want SRM levels of data quality.

If I am sacrificing 3% accuracy, I'm still doing better than using HR alone. I didn't have a HRM before, so spending an extra 40 bucks for HR deluxe/PM lite is hardly a serious imposition. For ease of use in training and bang for buck, there is no question that this is a good investment when you consider saving 200gms can cost hundreds of dollars. I suspect you might see a few successful names in Triathlon getting a bit of success from these over the next 2 years. There is a strong need for better TSS figures, and this could provide it.

It's not an SRM. Stop obsessing that it is. The power aspect DOES cost only 1% of an SRM setup. If someone can't let themselves accept that, you might want to wonder why you are so set in your ways despite lots of explanation to help you rethink?
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Re: Powercal?... really???

Postby twizzle » Tue May 28, 2013 10:31 am

Xplora wrote:And you don't think CycleOps is able to demonstrate an effective algorithm for that relationship?


No - I don't. Having run power analysis over my data files in the past, no two rides ever came up with the same relationship between HR and power. And that was just for my data, let alone trying to come up with an 'average' based on 'average' riders. My estimated FTP power is up 30W in two years, but my FTP HR is down by ~ 5 BPM. How would the Powercal account for that? The Powercal is a simply a toy.
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Re: Powercal?... really???

Postby Xplora » Tue May 28, 2013 10:46 am

twizzle wrote:
Xplora wrote:And you don't think CycleOps is able to demonstrate an effective algorithm for that relationship?


No - I don't. Having run power analysis over my data files in the past, no two rides ever came up with the same relationship between HR and power. And that was just for my data, let alone trying to come up with an 'average' based on 'average' riders. My estimated FTP power is up 30W in two years, but my FTP HR is down by ~ 5 BPM. How would the Powercal account for that? The Powercal is a simply a toy.

The fact that you have to ask questions, rather than answer them, seems telling Twiz. CycleOps has already said they are not sharing their algorithm. You've done analysis on your files. Awesome. CycleOps might have 1000 times the number of files you have, and for a certain chunk of the files this algorithm holds to be accurate within an acceptable % range. You might not fall into the group where this applies. I get the impression that the powercal won't be useful for every single rider because of the nature of the algorithm.

Ultimately, I come away from the discussion feeling like I've spoken to a jeweller who isn't happy with the new 10 pound sledgehammer on the market. It's not an appropriate tool for their needs, but it doesn't mean it's useless. It's a lot more accurate than the jackhammer we previously had, and while it's not a jewellers vice and chisel, it's a lot better than the alternative. Check out DCrainmaker's review. That's what did it for me. A hundred times more useful than nothing, but certainly a hundred times less useful than an SRM. My experience with my Bryton right now makes me wonder if I'd need to upgrade that if I did get a proper power meter... we can level these accusations at a lot of products on the market. Would a Garmin be good enough? :idea:
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Re: Powercal?... really???

Postby dalai47 » Tue May 28, 2013 12:01 pm

Xplora wrote:Check out DCrainmaker's review. That's what did it for me.


But note Alex's comment in this thread about DCRainmaker's review - 3rd comment on page one. There is a fundamental issue with the Powercal, therefore it is a power estimator only at best!

Note the price of new powermeters have come down a long way - Quarq's, Power2Max and even SRM's! And if you are willing to buy used can find wired SRM's under $500! Note I have bought mine all used and all work flawlessly…
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Re: Powercal?... really???

Postby TimW » Tue May 28, 2013 12:10 pm

I feel confident in saying that if Christine enters this debate, this thread will hit 20 pages :mrgreen:
edited :mrgreen:
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Re: Powercal?... really???

Postby Xplora » Tue May 28, 2013 12:32 pm

dalai47 wrote:
Xplora wrote:Check out DCrainmaker's review. That's what did it for me.


But note Alex's comment in this thread about DCRainmaker's review - 3rd comment on page one. There is a fundamental issue with the Powercal, therefore it is a power estimator only at best!

Note the price of new powermeters have come down a long way - Quarq's, Power2Max and even SRM's! And if you are willing to buy used can find wired SRM's under $500! Note I have bought mine all used and all work flawlessly…

And ultimately, that's the thing... they are all power estimators... upon reflection, if you're trying to measure something properly like peak power curves and making real time decisions based on that in a race (or spirited bunch sprint for coffee flavoured glory), then getting those low end PMs are a waste of time. We're talking about 1.5% variance in the best PMs... Friel uses 5% less power equals doubled time at a certain power. If you're using a 2.5% variance in your 500-1000 dollar PM, you're going to be potentially off by half of this "doubled time". for example, if you can do 300W for 60 minutes, you could guess that you've got 30 minutes available at 315W. But if your PM is telling you that you are doing 307W instead of 300W, then you aren't getting a useful pace. And you are paying 500 bucks for this?! Most of the older PMs seem to be in the neighbourhood of 2.5% accuracy. I can't help but think that 1.5% is worth spending proper money on.

But... while the PowerCal is probably going to be 5% out over the longer effort, I am not suggesting it will be useful as a critical pacing tool. I said quite early that it will be most useful for TSS values etc for which it is much more useful than just HR. If you want proper PM data, call Alex and buy a SRM off the bloke. Seriously. I don't think the PowerCal would possibly pretend to compete. But if you're going for a poke around on the kiddy trails on your old banger MTB then you'll get better TSS info than a HRM.

It's 40 bucks people. :lol: If you think its a toy, let me know how important your GPS data is. :wink:
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Re: Powercal?... really???

Postby twizzle » Tue May 28, 2013 12:55 pm

Xplora wrote:The fact that you have to ask questions, rather than answer them, seems telling Twiz.

It was a rhetorical question. Obviously... the powercal cannot account for day-to-day heart rate variations from simple changes such as hydration. It also cannot account for the slow-component VO2 changes on HR. It cannot account for the differences in HR observed between a road position and a TT position. It cannot account for when you have bonked.

An incorrect tool is often worse than no tool at all. And you could have used TRIMP scores for training.
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Re: Powercal?... really???

Postby dalai47 » Tue May 28, 2013 12:58 pm

Actually the accuracy values are always referred to as +- % So 2% is +-2%, so could be a 4% range.

Where does the PowerCal mention its estimated accuracy? Nothing on their site. If you claim the accuracy is +-5% - that is a 10% spread which is huge!

As to the cost only US$99 - is isn't the complete system. You still need the ANT+ receiver, and you may be surprised but many still don't have these... :shock:

My track cranks are the Science version so +- 0.5%. :wink:
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Re: Powercal?... really???

Postby vander » Tue May 28, 2013 5:28 pm

I think you are not understanding the debate here. We are not saying its not a useful tool. A HR monitor is a very useful tool many people have got great results from this sort of training and yes it is effective. Powercal is a HR monitor, so on that front its a good training tool. Powercal is not a powermeter is what we are arguing. Its power numbers means just about bugger all. It is an excuse for CycleOps to sell an expensive HR monitor to people that dont quite understand physiology that well and want to say they have a powermeter. Powermeters are not infallible either, Twiz has experienced this with his PM going out of calibration and giving him incorrect numbers.

Last point why do you think cycleops have so much data? A good coach like Alex will probably have seen a lot more data then cycleops. Once they sell the PM they do not see the data from it, its only in the testing stages that they would see the data or if people have issues with it. As oposed to coaches who would see all the data from all their clients and analyse at an indepth level.
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