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Is the Garmin running power measurement accurate?

Proletheus
3 months ago

Hello

I'm using the Epix Pro Gen2 with a chest strap and I'm wondering why, during a very intensive run for me, I spent 82% of the time in the Power Zone 1 "Easy".
My HR is in Zone 4.

Garmin automatically measures watts. I just don't know if and how the watch determines a kind of FTP (Functional Threshold Power) or if I should generally disable watt measurement while running.

  • 0 3 months ago

    In my experience, as a Stryd user, there is no absolutely correct "running power" figure. It's not as easy to measure as on a bike, for which I do have power meters.

    My Garmin power figure is always significantly higher than the numbers from Stryd. But, they track each other well in terms of the shape of the power graph. Therefore either one can be used for power training, but the numbers aren't interchangeable. Pick one or the other and stick with it.

    As to your results, I don't know how your running FTP was established. Maybe it needs adjustment to better align your running power zones with your heart rate zones. Personally I use my Stryd power and zones, so I've not dug into the weeds of his Garmin sets running FTP.

    Maybe there is something here that can help....

    the5krunner.com/.../

    EDIT : Added a comparative power graph for a 5k run. Garmin is solid grey and Stryd is the orange line. Stryd looks higher, but the scales are different, so it's very misleading. Nonetheless, the overall shape is quite similar.

    Better presentation using DCRainmaker Analyser....

  • 0 3 months ago

    You are right. There is a large discrepancy between the HR data and the power data. 

    You could test your data doing a field threshold test. Run 30mn at the fastest steady pace you can. You should be finishing at exhaustion. Take the last 20mn, evaluate the average HR and the average power. Multiply by 95%. You should be very close to your Threshold HR or yoiur Threshold Power. One of these 2 values will be wrong on your watch, most likely.

  • 0 3 months ago

    Exactly!

    This is due the fact HR takes much more time to go up while power goes immediately.

    Any variation on the terrain or speed causes the power to go up while HR doesn’t.

    Try to run smoothly on a really flat  track and wait your HR to stabilize and then after  make the math to math both zones. That will improve things but it will never be a match like in cycling .

  • 0 3 months ago

    Thank you for the many responses. I have now switched to "based on Thretholt Power" in the power settings. Now it seems to be roughly correct, and the rest will adjust automatically as I run more, since Garmin's TP is automatically adjusted. Previously, I had watts (first post) here.