This is an automatic feature that detects if you recorded an activity at the same time as other users, and on the same route. When we detect this, your activity becomes linked to any matching group activities and we display the group activity differently in your Dashboard Feed. When viewing an activity details page on either the website or from the mobile apps, you will also be able to see those other users detected as "also on this Ride/Run".
How Group Activity Detection Works:
In order to be detected as a group activity, our algorithm considers the percentage of elapsed time in your activity that the other activity is 'nearby.' If the other activity is nearby for more than 30% of the time, it is considered a match. This threshold allows for other users to join a group ride or run mid-way through, or leave early as long as they match the set percentage.
Troubleshooting Group Activities:
Timing: If you are having trouble matching to your group activities and you are a Strava mobile App user, try checking your device's internal clock settings. If you set your phone's clock manually, your set time could be over 1 minute off from the automatic clock from cell towers/satellites causing you to miss the group activity detection. Instead, try setting your clock to update automatically.