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Strava showing wrong power data for shorter intervals from Zwift workout

Mt. Kenya

Hi all, lately I've been noticing anomalies in the power data in Strava for a workout from Zwift. This has now happened a few times, only with Zwift workouts.
When I train outside with my Favero power meter, it works perfectly.
This is what happened:
- Export workout from Join to Zwift
- Workout done in Zwift, activity is uploaded to Strava, TrainingPeaks, GarminConnect.
The power data in Strava is very different from TP and GC. Especially for the 10-50 second intervals.
I'm following a training schedule from Join, which reads the wrong data from Strava, so it doesn't rate my workouts correctly, which makes pretty annoying.
I have attached screenshots from Zwift, showing the correct values. TP and GC also show the correct values, but Strava does not.
 I've already removed the activity from Strava, and added the fit file from Zwift again, but with the same results.
Using: Elite Direto XR smarttrainer connected via Bluetooth to Zwift on Apple tv. Powernumbers for longer intervals look OK, but for shorter, more intense intervals, they're not.

Anybody have an idea why this happening and is there anything that can be done about it?

Please let me know, thanks in advance!










Mt. Kenya

Currently having this same problem. Not finding any info on the internet about how to resolve...

Mt. Kenya

I’m also having the same issue and it’s just been happening the last few weeks so it’s definitely a new-ish issue. I’m not sure how to rectify it as the reply you have recieved doesn’t seem to help at all. Are you a further on? 

Mt. Kenya

Hi I have the same problem.

Has your issue been resolved?

Moderator Moderator


Thanks for posting about this. Please submit a support ticket and we’ll be happy to investigate further.

Jane (she/her)
STRAVA | Community Hub Team

Hi Jane, thank you for the reply.

I already submitted a case (#2549922) and this is the answer I received:

"I do see that there are some differences in the lap data, comparing what is shown within Zwift and what is displayed once the activity is uploaded to our system. 
This is due to how Zwift writes lap data to the FIT file. When you begin your workout, the first few laps will actually be missing valid activity stream data, basically it will look like there is nothing happening in those initial laps. Upon upload to our system, the missing data is automatically discarded, and laps may look slightly different overall.
This is simply a limitation of the integration at this time. Apologies for any confusion or inconvenience there."

Sounds to me like this is somewhat expected behaviour, but I don't really get it. Also, especially for the shorter intervals, it's not slightly, but a huge difference.

Why are all platforms reading the power data from Zwift correctly, except for Strava?

This is also how I replied in the case, hopefully somebody has an idea. I also looked at some older Zwift workouts from last year and most of them show the power data for shorter (sprint) intervals correctly.

Only since a few weeks, this is going wrong.

If anybody has an idea, I'd be happy to know, thanks!


Did you get the problem solved?