I have a friend who decided to run a half marathon with minimal training. He would over due it. He would go 10-12 miles once a week and then not run for 3 or 4 days afterward. I tried to explain to him that is not a way to train for a race.
He did not care, he wanted to finish the distance. I told him finishing is great, but it would be better to finish a shorter distance and continue to be able to run. Sure enough, the night before his race, he slipped and hurt his leg bad enough, he needed to take a shot during the race with some kind of medicine. During the race, he made it about 10 miles, before his legs gave out on him and he walked the rest of the way. The following night he fractured his foot playing another sport and is not done with running.
While the injuries did not occur during a run, I think they occurred because his body was in a weakened stated from over doing it.