You can add activity to the Strava website even if you didn't record it with a GPS device.
Simply enter time and distance for an activity (like a ride, run, hike, walk, etc). This is a great way to keep track of your training even if you didn't bring your device.
To do this:
- Log into Strava
- Click on "Upload" at the top right corner of the page
- Click on "Manual" as listed on the left side
- Select your Activity Type, enter the other required fields, and click "Create"