Do whatever, as long as it aint the straight bar. Straight bars destroy rotator cuffs over long and sustained periods of training!
Dumbells are the way to go!
And yeah, if you wanna totally screw your back up (and live in pain for the rest of your life), keep squatting and doing deadlifts!
Yes retards, prevent lower back and shoulder injuries by training smart. Avoid the bread and butter exercises.
