I use data fields on my Garmin that estimate virtual power and vo2max which are saved to the FIT file. According to fitfileviewer.com the fields are maxVpower, avgVpower, VO2maxSession and VO2maxSmooth. GarminConnect and SportTracks can display these for each activity. Is there a way to make these show up in Intervals.icu?
Reply to self: found a way to get a FIT file with virtual power data into Intervals.icu.
- Get the FIT SDK from Download the FIT SDK | Garmin Developers
- Use the FitCSVTool in the java folder to convert your FIT file to CSV
java -jar FitCSVTool.jar -u yourfile.fit
This will create yourfile.csv - Use a text editor to do a search and replace. The field name for the virtual power in my file is “curVpower”. Change all occurences to “power”.
- Encode the edited csv
java -jar FitCSVTool.jar -p2 yourfile.csv
This will create (and overwrite the original) yourfile.fit - Get the new file into Intervals.icu (I use Dropbox to do this) and the power data will be recognized.
hi,
Pls, which data field do use for virtual power? tks
I use the vPower data field from the Garmin Connect IQ store: Connect IQ Store | Free Watch Faces and Apps | Garmin. It will add curVpower to the FIT file. Use the procedure above to make it visible in your Intervals.icu stats.
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Have you found power values to be good for outdoors rides with that?
tks
I use it outdoors and it seems OK as far as I can tell.
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Please send me a link to one of your activities with the virtual power fields that you haven’t converted and I will have a look. Adding support for that is probably fairly easy.
Found out some more on power estimates.
Strava will calculate a power estimate for an activity with HR but without power data. (It seems the Garmin vPower data field uses the same calculation.) However, a sync connection to Strava will not transfer the power estimate into Intervals.icu.
There is a workaround: install the Sauce for Strava extension in your browser (Chrome or Firefox). This will add some extra options for each activity, one of which is a FIT download. The downloaded file contains the Strava power estimates that will show up in Intervals.icu.
Do you know how well curVpower compares to real power? I am a little worried about pulling this in as real watts if it is very bogus … I always found the Strava power estimates to be way off.
I have added support for curVPower and will deploy Wed AM (GMT+2).
Thanks! I will keep an eye on its behaviour. I believe it uses the same formula as Strava which means -as far as I can see- that there’s an overestimation in some of the cases. Haven’t figured out what triggers it.
Excellent! Syncs straight from GarminConnect now.
I noticed there is a column Power (“Power from real power meter”) in the activities list. Would be nice if this could be set to “No” for virtual power data. It’s “Yes” now.
Tx. That setting is a legacy thing from when Intervals.icu only connected with Strava. Strava doesn’t give out estimated power via the API so I ended up using that as a “ride has power” indicator. I need to do a bit of work to sort that out before I can use it as a “virtual power” indicator.
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HRtoPower is definitely better. The best power estimation results from all available fields. Provided it is customizable to your own FTP, LTHR, Based on heart rate, but the estimated power can be matched to that measured with your power meter by setting PWR Adjust +/-%. It seems to use not only the heart rate itself, but probably also the HRV, because it reacts quite quickly to changes in power and as soon as you increase the pedaling power, the field estimates more power than before. Of course, the cadence is taken into account, it can be used in stationary training, but there is the problem of increased heart rate drift with poor cooling of the body.
I use it in bikes in which I do not have a power measurement (e.g. MTB / CX), but when I compare the data from the field to the power meter from a road bike, the power is usually very close +/- a few% (generally up to + / - 3). Of course, it depends on the nature of the training, with short and strong intervals the accuracy will be lower, with a fairly steady ride you can get an almost identical estimate as measured with a power meter.
The use of HR data is quite convenient because you do not have to take into account changes in resistances, e.g. wind or surface.
The greatest discrepancy is at the beginning of the training, after warming up as the heart beats in the working heart rate, the estimate with the measurement is quite consistent.
Garmin Connect, unfortunately, does not take into account data from this field, in the absence of data from the power meter. I do not really want to manually combine with transferring data from the Developer field: POWER-2 (there are also fields HR2PwrA (average estimated power), PwrDiff (difference between measurement and estimation).
An example file with data containing the recorded power from the meter and the field: 206.2 KB file on MEGA
I sincerely recommend estimating the power with this IQ field, especially for owners of power meters in bicycles, e.g. road bikes and users of bicycles without meters, e.g. MTB.
Adding POWER-2 field support in the absence of registered power data would be very useful.
Thank you! I will definitely try this. Would indeed be nice if Intervals.icu could support it in the absence of regular power data.