John Donahurt has a very interesting way of thinking about Jiu Jitsu that reveals the chest of it, the like the science of it. I'm running in calisthenics and some things like that, but it allows you to still think about a problem. If you're going to a judo club or something you're, you've got a fixed start time. Or maybe seven o'clock or whatever, 10 o'clock on Saturday.