It's a charity baseball game in South Korea, and the players are comedians, show hosts, actors tv stars etc. They are doing what is called a 'chicken fight' where you grab one leg with one of your hand, and the other leg for balancing your body. Players must not let go of their leg or they get disqualified (or out). If an opponent rams into you and knock you off you're disqualified as well. Whichever team knocks out the other team wins. Alot of kids in Korea play this game, and not so violent as well. As for the clip itself, they staged a fight for entertainment.