I took Tae Kwon Do as a kid. I got a red belt with two stripes, but stopped going when my dad couldn't drive me for a few months. Not too long ago, I was hanging out with a friend who had taken classes with me and had earned a black belt. We were talking about stuff since we'd seen each other, a little over ten years ago and it turns out we'd both been in situations where we'd had the shit beaten out of us.

I asked him if any of the stuff he'd learned came to mind. His answer? "Nope." Granted, it had been a long time for both of us, but we used to go to tournaments and all that nonsense.

Most martial arts classes in America are for competition. It's treated as a sport and you're taught to pull punches. Martial arts generally teach practitioners how to react to certain situations such that reactions to certain circumstances might be good, but in a live fight would ultimately be useless. There are still people that practice real martial arts, but honestly the point of effective martial arts is not for defense in the sense that it can be used defensively. It's for hurting someone until they can't pose a threat, which realistically means crippling or killing an aggressor in as little time as possible.

I hear mixed things about Krav Maga, but I have no real experience with it. In the Philippines people practice arnis de mano or eskrima. Most people know it as stick fighting, but really it's about using whatever is on hand. It takes a whole lot to take a person down, a shocking amount and the best way to do that is with an implement, be it a stick or whatever you can find. This is something an aggressor will know and will probably be doing.