FTP and Power Spikes

As I understand your chart, if a short term power output exceeds what is expected based upon a user’s stated FTP then it is considered to be an anomaly and thus is eliminated from your analyses. Also, it is suggested that if the short term power output is not an anomaly, then this indicates that the stated FTP is set too low. My FTP as measured by Zwift and Wahoo Kickr ramp tests is about 199 and Intervals ICU pegs it at an estimated 194 and though I would like to believe it is higher I suspect it is an accurate reflection of my current capabilities. During a Zwift ride I just completed on my Kickr (spin down yesterday), I produced a 730 watt short term effort and many times in the past I have met or exceeded this reported wattage. Do you think that this is error produced by my Kickr or is it possible that, at least in my case, the algorithm that controls the Intervals ICU software does not provide an accurate description of my physiology. I am a boxing fan, and I know that in that sport, short term power is the last to go in an and aging fighter.

Thank you,
Russ Zeckner

I had a look at the graph for that ride and the power looked normal. So I clicked the “power spike detected” message and bumped the threshold to 30% and it restored the power. It seems 20% is a bit aggressive for you so I changed your default in /settings to 30%.

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This feature is really great, it appears to have fixed my unlikely 4 mins at 1500W which happened on a recent ride. Is there any way to export the new ‘fixed’ data and re upload it to Strava and Trainerroad? As it stands they are registering insane TSS!

Tx. Unfortunately the Strava API doesn’t support updating ride data so I can’t do that.

Did the ride originate from TrainerRoad?

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If you have a FIT file, you can use fitfiletools.com to easily remove the spikes.

It was an outdoor ride recorded on Wahoo then uploaded to Strava and synced to TR. Is there a way to download the corrected file? I could delete the Strava one and re-upload to have a correct file. It’s just annoying as the spikes gave me a TSS of something stupid like 780!

Thanks, sadly it was from Wahoo so not FIT. I tried converting the file, but it stripped all the data out.

Currently Intervals.icu doesn’t support downloading a .fit file for updated activities.

The other thing I could do is to support uploading .fit files (and likely others) to Intervals.icu, fixing the power and then uploading to Strava. You can upload new activities via the API. That is already on the todo list.

My thoughts were to fix the file - but no FIT format available, so no go - and then upload that to Strava, so it would show up automatically on intervals.icu. Your solution would work too, but the only advantage of that would be that you can attract users without a Strava account. Then again, most have either that, or Garmin Connect, so…

Ah, I see - in that case, fitfiletools will not work and although there are TCX editors, that would be much more of a hassle… In that case, syncing back to Strava would indeed be perfect, but I’m not sure if that’s even feasible. I know that Xert does that and adds some metrics in the remarks / notes field for you to view on Strava, but that’s on a Xert to Strava sync and not two-way. I.e., it’s not data from Strava that gets a ‘write back’ but it’s either a file import, or data coming from Garmin to Xert, which then gets synced to Strava.

jumping in here…I dont really understand the power spikes…on my rides I sometimes tend to get out the saddle and go for it. Therefore I would expect a large spike outside of my FTP.

In august my FTP was 250, it’s now 210 but I can still put out power for short periods of time that I was putting out at 250 FTP.

What setting should I have it set too? As I am training to get back to 250 FTP and above, so “spikes” would be normal as I gain my fitness?

The spike detection is relative to the assumed power curve for your FTP. So if your FTP is say 300w then the model says you can to 420w for 2 minutes. So if you do 20% (default spike detection threshold) more than that (504w) then it is considered a spike and clipped.

Issues normally happen with shorter durations if your anaerobic side is good. The solution is to bump up the spike threshold in /settings.

This is all a bit irritating if your power meter is always on point, but lots of people have PMs that do weird things when running low on battery etc. and just one ride like that trashes your power stats if it isn’t fixed.

Ok thanks David, if I was to set it to say 99% it would be what power I outputted, my power meter is always charged and updated so hopefully nothing funky is going on.

Yes setting to 99% will effectively turn it off.

For mere curiosity, my setting was blank, I guess it was the same as no spike detection ?

No in this case blank means “default” which is 20%.