Bicep curls, by Ron Burgundy. Yesterday I was chatted up by the manager of the gym where I (sometimes) work out. Cinco Pirouettas is a stout man in his forties who claims to have been a ballerino when he was young.  He spends most of his time talking to girls at the machines. He also bosses around skinny young men who appear to have never lifted weights before. He sometimes talks to mothers. “Did you do ballet?” he asked me point blank one afternoon, about a month ago.  I was stretching on the floor. Yes, I told him, a long, long time ago. He puffed up his chest. “I did ballet. How many pirouettes in a…