No saved activity after recording stopped. 😭 Can I rebuild it with average hr/power data?

[aaronbhend]

I always record my indoor cycling sessions with the Wahoo app.

Earlier today, I was about 20m away from finishing a 2h session when I noticed it had stopped recording. Turns out my phone had dropped to 2% battery.

I thought it disconnected the bluetooth to save battery, but then I noticed the bike and the Wahoo TRACKR heart rate monitor were somehow still connected. Anyway, I knew exactly where I was in the workout (just finishing the last interval and about to start the cooldown), so even though it wasn’t recording, I kept an eye on the numbers and finished the session.

I assumed it would save the activity up to that point… but nope.

So my question is: is there any tool that lets me create a FIT file (or another format) with time and average hr and power for each interval, so I can upload it to Strava and Intervals.icu?

I know I can add a manual activity, but without hr/power (and therefore training load), it doesn’t impact metrics like relative effort, fitness, fatigue, form, etc.

Is there any way to build a file with average values like this?

Any help would be very much appreciated!

[Gabriel_Vargas]

I would try downloading the activity CSV, editing it (adding rows with the known data), and then uploading it back.
I’m not sure if it will work, though.

[aaronbhend]

Thanks Gabriel!

I downloaded the CSV from another activity and edited it to match what this activity would have looked like. That was easy enough, but now how do I upload it to Intervals.icu? Or convert it to a format that Strava will take? I tried converting to TCX, but when uploading to Strava it failed with the message “Time information is missing from file”.

[Gabriel_Vargas]

Hi Aaron
I wasn’t aware that importing a CSV file back is a supporter exclusive feature. Please see more details about CSV downloading and importing below:

Download and upload activity streams CSV

All Intervals.icu users can download a CSV of the streams (power, heart rate, cadence etc.) for an activity for analysis in Excel, Google Sheets etc., on the activity data tab. Supporters can also upload the CSV to add or edit data. [Screenshot 2025-10-27 at 19.13.59] [Screenshot 2025-10-27 at 19.40.24] Google Sheets Do File → Import and select the CSV file. If the activity has any array valued streams (e.g. HRV or a custom stream using array values) then you need to untick the “Convert tex…

[aaronbhend]

Yeah, I noticed that too.
I think I’m gonna sub, but only after my Strava expires.

Anyway, I just checked the Wahoo app and for whatever reason now the activity is showing up… It’s incomplete, but it’s better than nothing…

Thanks anyway!

[MedTechCD]

If you have a very similar activity, you can change the date with fitfiletools.com and then import that copy on the set date.