Jerry Seinfeld says comedians stop being funny when they lose their physical strength "we talked about the the physical challenge of comedy which I don't think people think about...some of the really funny people funniest that I've ever seen like Michael Richards or Caesar. I've heard a lot of people talking about these guys like are crazy strong guys" "one of the things that will destroy your comedy is when you don't have any physical strength because there's an energy. Comedy is a concentration of energy on a point...It's like throwing a punch and it takes energy to do it" "a lot of comedy people as they age they just don't physically have the the juice"