I forget which one the logs support, but either the TCX or the GPX files that are downloaded from your watch and transferred are also stored on your computer, it's usally somewhere under C/User/Appdata/Garmin etc and you'll find it there. Having said that I'm not sure you can do a bulk upload (but I might be wrong). I just manually enter time and distance since I only log here for the challenges (100 runs, Big Kahuna, Fish) and use other platforms to actually analyze the data.

Sounds good. thank you.

Just to clarify, its under C/Users/*username*/Appdata/Roaming/Garmin/Devices/*deviceID*/History for me (Some of these folders are "hidden" in Windows so you may have to alter your map display settings to be able to see some of the folders). Another option is that you can usually export the TCX or GPX file from say Garmin Connect or Strava, but this would be a tedious process because as far as I know you have to do this for each activitiy individually.