Old injury, in my case, nearly 50yrs ago. Took out my ability to walk, for months. Eventually, developed enough strength and range of motion to be capable of moderate exercise. And, in time (a handful of years later), I recovered enough to get back the saddle doing many of the things I once did. But, I knew at the time it'd only be a matter of time before that amount of damage began to take its toll on the surrounding muscles that I'd learned to enlist in order to get around. As it turns out, while many of the more-energetic activities have been eliminated, cycling remains. It's one of the few things I can regularly do (along with rowing and "gym" [weights] exercising) to keep myself active. I'll be damned if I'll knuckle under. Despite the mess. Like the old Timex commercial ... took a lickin' but keep on tickin'. Wouldn't have it any other way. And I thank cycling every day.