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20 minute power calculation is wrong

I did an 80 minute indoor cycling activity today. The average power for the activity was 190 watts. However, the Max 20 minute power is showing as 172 watts in both the Android app and the web GC. How can that be correct, surely it must be >= average power?

On Strava, using the Elevate plugin, I see Max 20 minute power set to 196 watts, which is in line with my expectations.

Can someone confirm whether this is a bug in GC, or whether my expectations are wrong?

The activity is at https://connect.garmin.com/modern/activity/5476104500

Top Replies

Former Member over 4 years ago in reply to fishyweb +1 verified

fishyweb

not every second is recorded as I expected

did a recalc to every second with help of Fit File Repair Tool

check this file fishyweb-xxx-everysecondornot-5507594592-fixed.zip

happy & safe sport…

All Replies

0 fishyweb over 4 years ago

Is no one else seeing this issue? I'm getting it on just about every activity. E.g. today's 110 minute virtual ride is at
connect.garmin.com/.../5507594592 and shows average power over the whole activity as 175 watts, but the Max 20 minute average power as 162 watts. That is patently wrong.

Anyone else seeing this issue?

0 trux over 4 years ago in reply to fishyweb

Likely a problem with the imported data. Record the activity with a Garmin device, if you want to dispute the results with them. I do not think they'll take any responsibility for data comming from 3rd parties.

0 Former Member over 4 years ago

fishyweb

hi,

am I correct in the assumption that your uploaded data is not recorded in every second format ?

for a correct average connect needs data for every second otherwise you get what you see

or I am talking nonsense

happy & safe sporting

0 fishyweb over 4 years ago in reply to Former Member

The affected activities are uploaded from a 3rd party app - RGT Cycling - so there must be a connection here as @trux suggests above.

However, loading the same activity .fit file into Strava, the Elevate plugin manages to produce an accurate 20 minute power statistic, so it is not clear why Connect is failing to do so. I guess I'll just have to live with it.

0 Former Member over 4 years ago in reply to fishyweb

fishyweb

hi,

not answering my question

download the original from Garmin Connect and drag & drop the zip file onto your next post

zip first when the downloaded original is not zip already

happy & safe sporting

0 fishyweb over 4 years ago in reply to Former Member

5507594592.zip

Zipped .fit attached!

0 Former Member over 4 years ago in reply to fishyweb

fishyweb

thx for the feedback

will have a look at it

happy & safe sporting

+1 Former Member over 4 years ago in reply to fishyweb

fishyweb

not every second is recorded as I expected

did a recalc to every second with help of Fit File Repair Tool

check this file fishyweb-xxx-everysecondornot-5507594592-fixed.zip

happy & safe sporting

0 fishyweb over 4 years ago in reply to Former Member

You are right - that new file does indeed give a realistic 20 minute power value in Connect, the same value that I get from the Elevate Strava plugin with the original file. I wonder why Connect requires every second recording for their calculation, whereas Elevate does not.

Thank you for your help.

0 Former Member over 4 years ago in reply to fishyweb

fishyweb

no problem

happy & safe sporting