FTP estimate error? (FW 15.20)

After I performed a full swing FTP-test (the official' test protocol), my Fenix 6 suggested my FTP dropped significantly: from 296 to 280w. The 20-minute power produced during the test was 325w. Shouldn''t the estimated FTP be around 308w, or at least show an increase. Or is there a factor at play that I don't understand in the algoritm?

Workout file: connect.garmin.com/.../6318332134

0 mcalista over 4 years ago

The autodetect really detects Lactate Threshold Heart Rate, and tries to associate a power number with that. It is not based on 20 minute power.

I find it undershoots significantly my power via the 20 minute method.

You can always enter your FTP directly into Garmin Connect if you use the 20 minute or 8 minute methods.

0 eezytiger over 4 years ago

I find the same thing. It is as mcalista says. They care more for heart rate (and HRV?) response than your actual power numbers. Of course, there is a link, but they consider more than just the power alone. This is clearly not the normal approach and will probably mess with FTP based workout targets.

0 aukerensen over 4 years ago in reply to mcalista

That would explain, but it’s still weird that the detection relies so much on the HRV-based lactate threshold and does not cross-check the actual performance. Thinking of this, I had my running heart rate threshold estimate lower (169) than the average heart rate (174) during an sub-60 15km road race. The question is: how reliable and usable is the HRV-based lactate threshold detection for serous athletes?..