I've never played football. But you don't have to play football to know football. I know a lot of people who played HS football that actually don't know squat about technique or scheme, they were just physically bigger than other HS students. College football would be way more telling than HS, IMO. In HS its just about athletics, you get some brief introduction to scheming and technique, but its not till college when you realize you can't do it off athletics alone, because everyone is a better athlete, from the NFL your top notch athletics mean pretty much nothing. Everybody is one of the best in the world at their position, even the backups. You need technique and discipline to play at the highest level. But playing has nothing to do with understanding is the main point I'm making.