I know that most people have this issue with some part of their body . . . my bicep muscle on the right side (I'm right handed) is larger and more toned than my left. I try to add on extra reps, etc. for my left side, but haven't seen any improvements. When I'm carrying things, I try to remember to use my left hand. Not that it's a big deal, it's not like I'm competing and need a balanced body, just curious if anyone has had success in getting one side caught up to the other.