Hi,
Has anyone used the Powercal for Power/ TSS estimates?
Circumstances mean more commutes at the moment (no power meter due to bike security at work), and while I can use RPE in TrainerRoad, I thought the PowerCal might remove that need. Also, i’ve no power meter on my mountain bike, which comes out to play more in the winter.
I already use a HRM, and up until now have based the RPE on the HrTSS in Training Peaks. However, the calendar functions here and coming mean I’m ditching the Training Peaks account.
So is the PowerCal worth it for their estimates and the for my pure laziness at having to go in and update the rides? The reviews seem to suggest over a ride it’s not too bad - I wouldn’t be using it to train by, just for the TSS estimates really.
I did for some gravel rides. Far from perfect, but gets you in a ball park for overall stress. Try to ignore any peaks as it really gets odd at times. For steady-ish state rides, it is reasonable. But for interval type work, it really is no help.
I had one for a couple of seasons, prior to getting a PM, and looking back over those seasons my calculated power output on the PowerCal was a little on the high side. So much so that I have had to exclude all PowerCal rides from PRs as they are not an accurate reflection of actual power. Not a problem if you are using for TSS although it is likely to mean that the TSS given will be higher than your actuals. I put them in the same bracket as Virtual Power off a trainer.
Purchased one of these on eBay as I am travelling a lot and wanted to see if this could be of any help. The thing that strikes me about this device is that it generates a power estimate purely from heart rate, without using FTP or any form of user-specific calibration in the algorithm. Other apps (HR2PV) use FTP, max- and rest-HR as input, and can understand how that is used to calibrate a HR-power curve. The Powercal apparently does it purely based on the shape of the HR trace. That is pretty remarkable, and makes you wonder about physiology. So muscle- and blood composition don’t seem to matter much, it is the heart muscle that predicts performance…?
What they are doing is some decent guessing and association, but it’s fallible and should be used with some consideration & caution (largely because it can pollute your power data stream that may be related to things like AI FTP Detection or other power adjacent tracking).
Yes, familiar with that piece. It is what triggered me to buy an old one a decade later. DC Rainmaker is great in his analysis, but what is so striking is that he does not address the underlying mechanism of action. Without owning the device I always assumed there was some user-specific input (FTP) in the algorithm, but there is not and find that quite perplexing.
In absence of FTP there must be some second order analysis going on. There is the acceleration of heart rate that signals differences in power, but more interested in understanding how this device can be reasonably accurate when averaged out over a longer period of time. An elite athlete and amateur will have enormous difference in output at the same HR. So the device must be able to deduct stroke volume or something similar from the HR trace. Cannot find much in that direction online.
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