Today for the first time in my life I decided to try rowing in the local gym ergs instead of home. While i was rowing in this gym (the have the same c2 erg that i have at home), one of the gym teachers there came to me to correcy my technique. He said I was leaning too much at the end of the drive ("The Finish"). He said the back should be perpendicular to the floor at all times.
I ignored that advice as I feel it would put lots of pressure on my lower back, in contrast with leaning slightly at the end of the drive by simply using my own body weight, but the doubt arose: ¿how much should I lean back at the end of the drive?
I checked the concept2 website and in the "How to row" section it states -"Lean your upper body back slightly", so not much there for the detail I was looking for

So, I am interested in other opinions about the sweet spot on how much to lean in order to maximize the pool and avoid injuries.
So far, I feel comfortable with my techniche and I think the advise i was given in the local gym is not good at all for your back.
Thanks!
Saludos from down south
Gustavo