Some girls do. Some girls don't. There's no magic formula for making someone like you. Do martial arts because you want to do it, not because you're trying to pick up chicks.
Yes it is attractive, but if the guy is a jerk just trying to impress girls... Well, we aren't stupid and can see right through that. I do martial arts myself, and it is attractive when a guy has good form and trains properly, not just as a way to get chicks.
Lets put it this way, if the boy is a jerk, martial arts will not make him more attractive. Someone who is insecure about what they are doing is also not very attractive and unfortunately you sound very insecure having asked such a question.
A guy who is kind, considerate, respectful, has compassion and who is secure in what he is doing is attractive and will stand up for a girl not to boost his own ego but because he genuinely cares about others. That is attractive.
I am a girl and I find it very attractive. I am also in martial arts though. I guess it just depends on the girl.
You seem like a boy who's asking this in order to affirm your choice to train in martial arts in order to impress a girl. Well, each girl is different and you definitely cannot generalize. It wouldn't make any difference to me, personally.
Who's cooler? The guy who goes to martial arts class and wins at sparring? Or the guy who stays at home and knits sweaters?
Do you find that attractive or do you find it stupid and so on..