Running is a high-impact sport which makes succumbing to some sort of injury quite common, especially the longer you continue with the sport. You can mitigate this risk by doing things like run-specific strength training and following a well-constructed running training plan, but even then things can happen—I once scuppered a marathon training cycle by banging my knee on a radiator jumping across a room to impress my toddler.
When an injury does occur, it can be devastating. Not only do you lose out on the physical benefits of the sport and lose any improvements in fitness you had gained from training, it’s also hard on your mental health to not be able to participate in something you enjoy, especially if you’re friends with runners still training and taking part in events.
