As runners, we’re accustomed to hearing that we’ll “ruin our knees” and other nonsense, usually from someone who uses that colloquial wisdom as an excuse to be a couch potato.  And although I find those people to be irritating, their assertions don’t trouble me.  Given the alternative of being a couch potato, I think my knees are better off belonging to a healthy-weight runner, thank you very much.  Yes, every time someone makes a comment about running ruining my knees, I want to say something snarky like, “I hope that can of soda doesn’t ruin your pancreas.”  So yes, I still find the insinuation oddly annoying.  However, it doesn’t give…