This is a Strava Premium feature:
Strava provides the option for Premium members to download or export the route data of another Strava athlete's activity. This data can then be downloaded onto a Garmin Edge device to use the map or courses features.
If you have a Garmin 800, 605, or 705, getting a GPX file on your device is easy. On any activity page you’re viewing, you’ll now see a “GPX Download” button located at the top-right corner of the activity’s map. Click this button to download the GPX file to your computer.
- Plug your Garmin device into your computer.
- Navigate to the Garmin drive on your computer and find the folder labeled “Garmin”. If you have a Garmin 800, inside the Garmin folder is a subfolder labeled “NewFiles”. If you have a Garmin Edge 705 or 605, the subfolder will be labeled “GPX”.
- Simply drop your downloaded GPX file into this folder and then safely disconnect your Garmin as you would any other USB device. (The method used to get the downloaded GPX file on your Garmin device will vary based on your computer setup, but in general, you can think of your Garmin as you would any other USB drive.)
Now when you turn on your Garmin Edge device, you should find the route under the “Courses” menu and you’re ready to go.
For Garmin 500 devices, the "Courses" feature requires a TCX file to be downloaded onto the device.
GPX files are tied to an athlete’s Privacy settings, therefore all activities available for export are stripped of any performance data upon download and respect Privacy Zones except for your own file. If an activity is private, only the athlete who owns the activity will be able to export the GPX.
There are some cases where you won't be able to export the GPX file of another athlete. If an athlete has Enhanced Privacy turned on, and you do not follow that athlete, you won't be able to download their activities.
For instructions on how to Export GPX files from your own activities that include time data, see here.