In my middle-school days, there were some very sharp guys teaching in part because of the Vietnam draft. (No, I'm not young anymore.) At my high school (all boys, Catholic), the coaches had to teach real subjects: Algebra I, Trig, Plane Geometry, Biology, Chemistry. Now, one of the wrestling coaches sent a classmate of mine hurrying to the other class with his statement that a milligram was one million grams, but most of them seemed to do OK. Not all of the other male teachers were in orders, either, and most of them, lay or religious, ranged from adequate to good.