Actually, Im on 15 and since youre older you should know that barbell rows gives you back muscles,
Which helps stabalize and gives core for when your benching.
Power benching, (being able to push up the bar fastest you can with force)
Comes good with arm muscle, chest and back muscle.
That helps you cause to keep straight and being able to bench more and heavier..
I had no idea that you were a power lifter O.o yes arching your back will engage the muscles in the back which will help your bench press...but if you're goal is hypertrophy then you shouldn't be in a powerlifting stance. I mean obviously working your back is essential and you should do back rows, however, when you're benching (bodybuilding style) your back doesn't come into play. The goal to bodybuilding exercise is to get as much outer influence away from the movement. I.e. you hear that saying "Lift with your legs not with your back". This is good advice for a perhaps a piano mover but not good advice for a bodybuilder. Bodybuilders should in fact lift with there back. Of course you must do what is right for you and this is just my 2 cents worth. You will still use the chest if you are in a powerlifting stance for bench press...but not as much. Stay safe!
