I am a run-shuffler, and I tend to have problems on sidewalks and trails when I am not paying attention. I also run with my dog, which further takes away from my sightline, and sometimes I fall.
Sometimes the sidewalk will actually grab my foot and make me fall, and sometimes a tree root will spring up as I cross it mid-stride. Sometimes, I am just lazy, and I trip and fall.
I remember one time I was listening to some music while running with our two dogs. It was winter, and I was coasting along down a nice clean sidewalk when suddenly, the sidewalk reached up and tripped me. I run with a skijoring harness, and I am attached to the two dogs. So when I ski, they can pull me. My fall went something like this: Start falling, twist to try to roll onto my back. I was not injured, and the dogs pulled me another foot or so down the sidewalk. Fortunately, they stopped pulling me.
The key to this story is to learn how to fall. You don’t want to put your hands out, and you don’t want to use your face to stop the fall. I had a year of Aikido training, and something stuck in my head to make me try to roll. Don’t get me wrong. I am not out there falling every day. But I do fall, and most of the time, I end up on my back.