Should the upper or lower back be arched, and how much? If so, is it better (muscle-gaining wise) to arch it or keep it flat? Me and my friend have different opinions. I just want to see if I'm right.
The Bench Press if you want to move more weight arch if you dont care then dont. i would recomend arching tho
The Bench Press Powerlifters tend to arch their back and lift their asses off for bench press. The back should be arched when doing bench press, chest is put out to put more stress on it
The Bench Press Powerlifters dont lift their asses off the bench wouldnt count in a meet they keep an arched back and chest up very high to limit the range of motion. Less ROM, less distance to move the weight = easier bench press.