I want to train in Mixed Martial Arts at a local place, how do I tell my parents?

I want to train in Mixed Martial Arts at a local brazilian jiu-jitsu place. Luckily, its only about 3 blocks away. How do I tell my parents I want to take something that involves fighting? It's not a money issue it's just that I don't want my parents to think I'm some type of crazy obsessed kid with fighting. I mean I've always liked fighting throughout my life even when I was a little kid and they know that. They laugh because my grandpa loves doing that stuff too but how do I tell them? My parents are usually pretty relaxed about things but I want a non-awkward way to tell them. Thank you for any suggestions!

I want to train in Mixed Martial Arts at a local place, how do I tell my parents?
Tell them it will teach u responsibility, control over your emotions, poise, how to give respect etc. Every one should know how to defend themselves!
Reply:Just tell them you're taking "martial art classes" in a safe supervised environment, to improve your mental discipline, physical health, overall well-being, etc. If they ask what kind of martial art you can honestly say "it's generic, like a mix between judo and [whatever martial art they might be ok with]"