I had to drop my kid off at a birthday party which was being held at a local fancy health club. While waiting I took the tour and listened to the sales pitch. While talking to the Member Services lady we talked about past gyms and clubs I have belonged to, and my running. I said how it was really working out for me (unlike gym or martial arts) because you can do it any time and any place, the flexibility has helped me stay with it to where I ran some HM's last year, etc. She said "that's great, but once you turn 45 you'll have to find something else." I laughed and asked why. She said running really messes up your knees. She mentioned "people" who have knee surgery at 45 and can't figure out why – hell-oo – it's because you're running 10 miles a day. Out of politeness I didn't take her on. Now I know her position makes her extremely biased, and she probably has a personal example that "proves" her prejudice. But it bugs me when people present this as if it is known fact (a less informed person might take it as such, coming from a "fitness professional"), and it is the runners who have been duped or are operating under misinformation that it is good for you.
I was reading a self-help website promoting purposeful walking (pedestrianism?) as a means of increasing your daily exercise. All for it, but then there is a clever reference to "without being a slave to the gym, or grinding the cartilage off of your knees running."
A local radio host who was watching the local marathon, which goes right by his residence, goes off on an (annual) diatribe against running, using the "pained expressions" on people's faces when they run as proof that it can't be good, and yet thousands of people put themselves through it in the name of fitness, at the cost of their future knees.