I'd just like to point out that Zombies, logically, would be just as subsceptible to injury as anyone else. They'd still have bones to be broken. You want my opinion, best thing to do when faced with a horde would be to spray machine gun fire below the belt, to cripple as many as possible. They'd drag themselves along, sure, but I think we can all agree they'd be considerably less dangerous.

Or you could just ascend a particularly steep staircase, that might also work.