Almost everyone I know has a chronic injury of some sort. Maybe it’s a lower back that needs extra warming up before a long day, a knee that gets stiff on cold nights, or a tweaked shoulder that prevents good overhead positioning. They’re usually not crippling, debilitating, or otherwise serious infirmities, but they are injuries that limit quality of life and performance. And all those people, to a person, got their injuries from training. My understanding is that this is true for most people who exercise regularly. Injuries happen to everyone.
It’s possible that I’m experiencing selection bias. Perhaps the injury history of the general exercising public isn’t anything like the history of my circle of ex and current endurance athletes, serious fitness buffs, Ultimate Frisbee enthusiasts, and otherwise active individuals. But I’d wager that most people who step foot into a gym have a nagging injury of some sort. The research suggests injuries happen quite frequently.