One hundred meters back you start calling out. A simple, “Good morning,” usually works but some need to hear: “passing on your left!” before noticing someone coming up from behind. Then there are those special snowflakes who pretend that the sidewalk, road or trail is their personal treadmill. You holler, yell, even shriek, but they don’t acknowledge you.
This is fine when these people stick to the edge of the path, but they inevitably drift to the middle, cutting off everyone else. You give them as much space as you can yet they still gasp in shock, curse or complain when you run past them. If they can’t care enough to pay attention, why care enough to curse at someone just because you were surprised by a faster runner or bicycle. Clearly, some people should never be allowed to run in public.