(cough) highway=path (/cough) 
The case I’d make here is that functionally the running track, the downhill cycle track and my “horse gallops” example do have things in common:
- They’re for people taking part in (or preparing for) something considered a sport
- That sport is non-motorised
- The “way from A to B” isn’t shared with a bunch of people who are just trying to get from A to B; it;s specifically for the sport/leisure activity.