I play netball, there doesn't seem to be an activity for it. When I set it to anything whilst I'm playing, it seems a message to my emergency contacts. Any clues?
Have you checked the settings for "Safety and Tracking Features"?
https://www8.garmin.com/manuals/webhelp/vivoactive4_4S/EN-US/GUID-64F677A5-03E0-453F-BFE3-E1B93D6FA3FC.html