Baseball backstops are usually of the chain link variety, so why not the same for skateboarders? All that's missing is an umpire to call him out, or a cop to wail on him for skating on public property.
Don't fret too much for this guy. Not only because he's a skateboarder and therefore beneath your pity, but also that he shows a clear display of cognizance in being able to identify what part of his body just got mashed against a fence. Let that be your rule of thumb when throttling punk grinders. If they can scream out the part of the body you're damaging, they're not really all that hurt. If they scream "brains!" they're a zombie. You should probably run then.