No Hip Replacement Please

I’ve wondered if all the exercising I do with weights and running and jumping is leading me to hip or knee arthritis at the same time as it’s making my muscles and heart stronger. Could hard exercise be good for the muscles but bad for the joints?
I was happy to read this today in an article about cyclist Floyd Landis and his upcoming hip replacement:
“While it may seem as if all that bike riding before and after the accident contributed or even caused Landis’ problem, surprisingly, experts say this is not the case. ‘Cycling did not wear his hip out. There has never been a scientific study showing that any sport leads to arthritis of any joint. Injury is what leads to arthritis,’ says Michael Bronson, MD, chief of joint replacement surgery at the Mount Sinai School of Medicine in New York City. Moreover, he tells WebMD that continuing to ride may have actually helped the problem, allowing Landis to maintain a significant range of motion, which in turn allowed him to function better than if he were a couch potato.”
I hope this is correct. I know of way too many middle-aged people who have had, or have been told they should have, a hip replacement or two.