If you floundered, whack. If you complained bigger wack. If you tapped out through exhaustion whack. His rule was 'you've had enough when I say you have'
Strange as it may seem we liked it and it took us to getting through barriers we were sure we couldn't.
I'm not going to say your teacher was abusive. I wasn't there. But I will say that this precise attitude is how situations that are abusive continue: the survivors view the experience as strengthening and/or empowering. "That which doesn't kill us, makes us stronger."