Managing Grade 8/9 Boy's in P.E.

First of all, I can't say enough about my two week practicum. It was an incredible experience and I learned a lot from both my mentor teachers. However, one thing in particular kind of bothered me. My mentor teacher for the P.E. classes seemed to be incredibly strict when it came to dealing with his grade 8 and 9 classes. His presence in the gym was always known, and it seemed that if a student had even a smile on his face when Mr. H. was instructing, Mr. H. would stop talking a stare down the student. I will admit that the class listened to every thing that Mr. H. had to say, and he had very few managerial problems, but I remember my grade 8 and 9 teachers doing the same thing and it almost made me want to drop out of P.E. (my favourite class).
I guess my question is whether or not other people in this class had those same types of experience. Is this fear tactic simply the only way to keep grade 8 and 9 boys from killing each other in gym class, or is there a more friendly way to go about it? I for one hope so.