My 6yo staryed Tai Kwon Do and still does 2y later. The nice thing about it is that there are different disciplines. Style or fighting. So they find something they like. He also said that he needs it now. Although after a year he wanted to quit. He stuck with it and now he misses it if he misses training. Don’t know karate. For what it’s worth.
An episode of Batman including Catwoman?