I don't know how true this is. I've used dumbells for years and my left arm has always been stronger doing one arm dumbbell curls. I can always crank out one or two more with my left arm even after my right is completely gased. And as much as I've tried, the right arm never seems to catch up. Which is odd considering I'm right handed. (makes me wonder how strong my left arm would really be if I switched it up, so to speak )....I don't believe that you can attain true balance when it comes to strength. Whether using dumbbells or the barbell. The key is to look balanced, and even this can be hard. All this said the routine outlined by IW was not an advanced routine which would incorporate isolation movements using dumbbells but one based on the fundementals and compound movements used by a beginning bodybuilder to not only shed unwanted bodyfat but build bulk.