Interesting when you look at it this way, is punching any more a martial art? What makes a martial art? Now this is a very individual thing the word we are describing, maybe running could be part of someones individual art if involved in the self defense aspect of it all. I can go on forever with philosophical points of view, I think most would agree that for it to be a martial art it would have to involve combat, but for an individual a definition of a non physical thing, can never really be a fact, unlike say water which we know is hydrogen and oxygen. For me personally I would say no, but if someone thinks martial art is how they live and embody it everyday then I can't argue otherwise. I have always said parkour and martial art are like cousins, I think for self defense they compliment each other very nicely. There are certain times you may have to fight and certain times you may have to run.