Today, I'm lounging in Battery Park, the world's most valuable landfill. During my travels here, I used the bridge near Stuyvesant High School, and observed a tennis game being played.
I realized that the more upper class a sport is considered (tennis, golf, sailing, polo, formula one racing), the less physical activity involved. Of course, that does not mean that the hoi polloi (that's Greek for "the great unwashed) cannot also enjoy these sports. Nor that there aren't low effort sports for the masses (Bowling, for example). Perhaps the leisure activities which don't require money aren't considered sports (like watching television). Or there is little money to be made, so companies do not market the activity with special shoes, clothing, sponsorships, or paraphenalia.