If you record activities with Wahoo's SYSTM (formerly The Sufferfest), you can automatically upload your activities to Strava by connecting your accounts. If you choose not to upload a specific activity to Strava, click the Strava icon when you complete an activity, but before you click Save.
In the SYSTM app:
Navigate to More > Settings > Authorized Apps > Strava.
Authorize Strava by logging in and confirming permissions.
Ensure that the box next to 'View data about your private activities' permission on the Strava authorizations page is selected.