Lately I have started to use my Garmin Fenix to record my indoor virtual rides on MyWhoosh as a recent update to the platform caused them to remove the garmin edge as the default computer as the "device" used. As a result no training effect is being calculated anymore, so I started using my Fenix.
I did a workout this morning that was predominantly in my zone2 HR however the power was predominantly in zone3 when my ride finished and I saved the workout on my watch it told me it was High Aerobic (tempo) with a score of 80 or so.
I then downloaded the fitfile and used fitfile tools where I could add a device (edge 830) and reuploaded the file to compare and to my surprise it showed a low aerobic activity (base) with a score of 79.
I always thought that the training effect was primarily HR based, are new devices or watches using a different calculation where it also now looks at Power Zones?