Map My Run not registering on Workouts
I use Map My Run to track my runs. It has an Apple Watch app. However, when I open the "Activity" app on my phone and go to the "Workouts" tab, it has logged all the runs i went on over a year ago using the Couch to 5K app, but it doesn't log any of the runs I've done using the Map My Run app. Does anyone know how to fix this? I didn't do anything specific to let Couch to 5K share data with the Activity app, it just did it automatically. I don't know if it's a matter of Activity not supporting this particular app or if there's something I need to do so it will share data.
Apple Watch, iOS 10.3.1