The immortal argument in my thesis paper is discussing the interesting argument of why some things are a sport, while others aren't. Chess, Poker & Magic the gathering vs Football, Baseball and Nascar.Look at a dictionary, key words are physical exertion, but it doesn't define how little or much counts.
I'm not an athlete. I don't claim in the slightest to be one. I'm more of a thin art person. However if the definition is to have physical exertion then chess, magic, and any other things like have been mentioned require physical movement yes, but not exertion. Exertion mean a large physical effort. I've played chess, Magic, and poker and I would never consider them sports. Games, yes, but not sports. Sports in my mind have a set physical requirement depending on the sport. Football requires you to be able to add 15+15+15+15 and have it equal 4 hours for some reason.