Activities via: https://www.strava.com/api/v3/activities
Shows "elapsed_time" in seconds but if the activity is longer than 24hours it seems to only contain the remainder after the first 24hours
e.g.
https://www.strava.com/activities/3886452961/overview = 27:52:15
/activities returns:
"elapsed_time": 13935 = 3:52:15
https://www.strava.com/api/v3/activities/3886452961 returns: