[Mr Rogers]

"Or runners who need hip and knee replacements by their mid forties, sometimes two replacement each."

As someone who is still running at 60, there is no way to know if running in your 20s will damage your knees or not. But if someone has problems with knee pain, and they run, then "Walk" might be a good prescription. Or "bike".

"Doctor! Doctor! Every time I play tennis, my elbow hurts!"

"Stop playing tennis. That will be $20!"

[rktman]

“It hurts when I do this.” “Quit doing ‘this’ then.”