Give the option of grouping multiple activities from the same day in one post to avoid clogging up the feed with warm ups/cool downs etc.
Activities grouped together would be able viewed separately when clicked on, or could be scrolled through by swiping through on the feed screen. This would allow athletes to separate their activities on their watch if that's what they prefer to do, while reducing the amount of separate activities for the day and still sharing the information about all parts of the run.