Incorrect power meter data

[erlendostbye]

I have a 4iiii power meter, and i have discovered that there is a discrepancy between the average power i displayed in Garmin Connect and Strava. On my last ride Garmin claimed 223W, while Strava claimed 167W (Not too big numbers... hehe). That 56W in difference. I have checked that the power meter is registered, and that Strava does not estimate the power. Does anyone know how to fix this? 

[Johndinis]

Hi. 
completed my ride this morning, avr power was 190w and calories 847 

two hours later I checked on the app and the avr power has now dropped to 97 and calories dropped to 420 

how is this possible after morning ride has been done and completed 

[rafiniv]

Yes. I changed my setup in the Garmin to include zeros when calculating power!
I set the same settings as my friends.
It seems to my friends that the data from the Garmin app goes to Strava exactly as it is on the Garmin without any additional calculation on Strava.
For me, they are probably calculated in Strava, so I get a much lower result.

[Jane]

Hello @gerardgonzales and @rafiniv 

Thanks to your both for posting.  Have you tried changing the setting on your recording device to include zeros when calculating power?  If not, I would recommend giving that a try.   

[Jane · Accepted solution]

Hello @erlendostbye 

Thanks for posting about this and apologies for any confusion.

Weighted Average Power is similar to - but NOT the same as - Garmin's Normalized Power.
Both numbers attempt to capture the average effort of a workout by taking into account lactate accumulation and other types of fatigue. Strava uses an algorithm very similar to xPower for computing Weighted Average Power.   Find out more here. 

There will be differences between the Weighted Average Power and Normalized Power. How much and which direction will depend on the ride. Typically, for shorter rides, Weighted Average Power will be lower than Normalized Power.

This is a result of the different types of smoothing used by the algorithms. Both numbers have been used successfully by professional coaches.

Another thing to keep in mind is that on Strava we do not remove any sections of zero power from your data before we do our calculations.  Whether or not your Garmin power calculations are including sections of zero power depends on your Garmin settings.  You can check the Garmin Support site to find out how to adjust this setting if necessary.

I hope that provides some insight into this.  Please let us know if you have any further questions.

[Dicker01]

My question is the between Garmin Connect and Strava transfers a lot of data why is it not possible in this case you take also the PWR data from Garmin? If there is no Garmin Connect connection you can make your own calculations for standalone user thanks from 🇦🇹✌️

[BaldEagle]

Jane wrote: "Another thing to keep in mind is that on Strava we do not remove any sections of zero power from your data before we do our calculations."

Yes but Strava seems to be also including times when the ride is paused as 0W .. or better said: the bike is stationary - say at traffic lights and Strava includes this time as 0W in its calculations.

This is obviously incorrect and needs to be corrected...

for example today I did a a shortish ride and Elemnts & RideWithGPS apps both show average power of around 120W but Strava only shows around 50W.. this can't be right and I don't believe it is because of including times of 0W when the bike is moving... If I hadn't been pedalling for more than half the time I was moving, I don't think I would have got very far...

Please Strava correct this problem - or at least give us the option to exclude 0W in the calculations as many other cycling apps do..

[Jan_Mantau]

Usually Strava doesn't include the time and the 0 W when someone pauses. I did a ride with 1.25 hour moving and 1.5 hour pausing today and the average power in Strava was correct. It's possible that Strava didn't recognize the pause at traffic lights when the GPS is drifting and therefore some speed is detected.

[PK10]

Hi Jane. 
appreciate this is old but wondering what Strava’s reasoning is for not letting users decide what they want to see? Thx 

[Caa12k]

This isn't good, we want to exclude zeros as we want to see our workout for real in terms of average power produced, it doesn't matter about the rest period which in turn Strava is lowering our real numbers, please add the option like Garmin to exclude zero, and not change our data.