well i started incorporating lunges again. Actualyl felt real good yesterday, but squat was shit. I'm guessing cause my lower back was a lil tired from something, woke up having that minor feeling. So i guess my back gave in before my legs do.
If you're talking about normally, i always try maintaining a straight back(i'm not those crazy flexible ppl who could arch in the first place, so i'd said archign wont be my issue), but might probably round a little once in a while.
Yesterdya was bad though. My middle back(lats?trapz?) was the weak chain in my squat. on my last rep, the 4th, i actually unconsciously rounded it as i was close to failing. even in deadlifts my middle back gives in , which i'm correcting of course.