It says everywhere that he practices aikido, but IMO he's kind of a shame for aikido Aikido is all about warding off the other without any harm coming to him, so after a while when he realizes his ways are ineffective, he can just stand up and walk away.
Cool vid, although it would have been a lot better if some shots were a bit longer and when a he had put on a musictrack from himself instead of an other song every 3 seconds. @Pablo: Agree. I always liked Jackie Chan's fighting skills better, he makes sure that his opponents are out without doing much or any permanent harm. The kind of fracture Steven brings will never completely heal.