> If you're in a running club I bet you do too.
I'm not in a club but am a runner myself, although currently in a trough ever since I got a kid, and in the process of picking the habit up. I do know a bunch of long-time runners far above my level (a couple doing trail). Most injuries I heard about are ankle or knee sprains. When tracing the root cause of injuries most of those appeared to be:
- accidents (an overlooked hole or bump in the ground)
- skipping (or rushing) a warmup
- seeking performance or improper recovery, thus soreness/tiredness during effort, thus pushing it into the area where muscles and tendons could not compensate for the strenuous effort anymore.
My mother's SO has been a runner (and bike rider) for most of his life and is still running and riding despite nearing its 70s (TBF he is dialing it down, mostly because of age). AFAIK he never had a serious injury due to running; he certainly does not have lasting damage. One key thing seems to be that except in his early youth he's never been looking for performance, instead it's more of a lifestyle habit for him. Effort, yes, strenuousness, no; the long scale game not being a marathon or something, the long scale game being several decades of healthiness.
> I don't know any cyclists or swimmers where the sport by itself has caused that kind of damage.
Conversely, I do. Again it's a performance seeking scenario. There's a swimmer who started to have severe back issues (started with butterfly, a few years later he could only back crawl). A couple cyclists started to suffer knee and hip issues because of the repeated continuous pressure heightened by leaning forward during a high-lever effect ~90deg (well, closer to 90deg than when running) pedal push. Several suffered chronic Achille's heel or popliteal tendinitis. Again, a performance seeking scenario, combined with an apparatus that that allows you to go "beyond spec" to eke out the most energy-to-speed ratio.
That said bikes are brilliant, and extremely efficient at transforming downward energy into forward motion.
> I can ride a 150 miler when I'm not that fit or flexible and once the tiredness has worn off I'll have no issues
The above efficiency note biases bikes a lot. My previous comment was not an argument against bikes at all, it was about trying to dispel the blanket canned statement that "running is the worst and very damaging to joints because impacts, you should not do it".
> I remember running a half marathon once when I was fit but without a long, structured training and I was limping around for a week afterwards.
However you slice it, a half marathon can already be quite straining and requires, as you mentioned, intentional training to be achieved without damage in our modern societies. Now, running a 5K three times a week at a brisk but not strenuous pace should not produce any damage if proper form is used (assuming bad form all bets are off anyway and even 1K could easily smash your joints and back if one constantly hits heel first, but then again bad form on a bike can be quite disastrous as well).