[HoneyBadger]

As far as representing martial arts in a game-if the game we're talking about is Dom3, for example, you might consider that applying a specific martial art to a "basic unit" might give, for example: an additional fist attack (boxing, or striking martial arts), defensive points (aikido), protection (iron shirt), kick (kickboxing, savate, tae kwon do), movement (monkey style kung fu, capoera), claw attack (tiger style kung fu), extra hitpoints (drunken boxing), size (sumo), magic resistance (tai chi, dragon style kung fu), attack (dueling/fencing), stealth (ninjitsu), strength (pankration, Indian wrestling) or spiked armour (grappling forms).

Ofcourse, these are broad generalizations, but they would debatably relate, in some way, to those in-game abilities.