Your going to have to become very aware of how you treat your back the other 23 hours a day you're not working out.
I know I've harped a lot on what you can do in the gym to keep your back healthy but you know, you can't make up for what you do MOST of the time with what you do during a couple of workouts a week.
A case in point..I very flexion sensitive. My back cannot tolerate long periods of time in a position of even slight flexion (lower back I mean of course).
I was reading Mcgill and he was saying how it was counterintuitive, but people who are extension sensitive then to seek out positions of extension and people who are flexion sensitive then to seek out positions of flexions. Weird but...
I realized this is EXACTLY what I do. I just realized I was doing it as I typed this.
So that is an example of the kind of thing you need to become aware of, I guess.