This seems like a throwaway episode. It is predictable and not very funny. It's the old "put one over on the wife" things that shows the writers were suffering from a block. Anyway, Ralph is set to have a physical to keep his job. Alice wants him to go to her mother's for dinner. He tells her he needs to rest up, but it is a ruse to go bowling with Norton and his team. Alice catches them as they are leaving and he acquiesces and decides to stay home. He has had back trouble and can't afford to hurt himself. That is, until Norton starts putting on the peer pressure, shaming him. The rest is pure formula and kind of sad. Also, there is no real satisfying conclusion.