Meeting every Sat for a 5k run is not a community of practice, but it is a community of runners who share a common interest in running. Regular interaction and shared experiences is a fine thing. Organisation around the transfer of knowledge and experience to solve a particular problem makes it a community of practice.
For too long now sports have been organised around the development of the sport itself and not the people who play it. Perhaps it’s time to acknowledge and name the problems we see in society based on inactivity and organise ourselves around them, not the badge on our tracksuit.