Being a gamer doesn't count, because you're still staring at a TV/computer screen, and your easy chair has a firm grasp on your ass. Why do you think Wii has a boxing game that is themed after Hajime No Ippo? To counter the grasp of the easy chair. But even then, it's still a computer game.
I know that incompatibility between anime and jocks is largely a stereotype, but there is *some* basis in reality. Most of the people in anime clubs in my area (West Coast US) are not very athletic, and in fact overweight. Based on just that, I would say the stereotype is being perpetuated. But... after I understood the situation better, I realized that most of the anime watched by the aforementioned anime clubs was not sports-themed, but rather fantasy-based stuff like Naruto, Dragon Ball and Cowboy Bebop. Jocks see the same thing I do - unathletic people watching some boring stuff - and make conclusions based on what they see.
I watched some of the same stuff that jocks enjoy - think "Top Gun" and "Rudy", and enjoyed them. Most American jocks simply don't know about stuff like "Slam Dunk!", "I'll/CKBC", "Prince of Tennis", and "Eyeshield 21", all of which are just as good as "Rudy". Based on that, I can say that while the anime/jock incompatibility is just a stereotype, it arose out of several factors. One is - people do perpetuate the stereotype in real life. Two - Understanding of anime is very limited, and jocks have their sports to worry about. For example, in "Slam Dunk!", does Sakuragi go to movies or other entertainment? He may sometimes try to sneak into a pachinko parlor with his friends, but he usually does not have the time for that, he's in the gym training his ass off!