toning vs. mass building


I've never really understood the whole thing of low weights/high rep and vice versa. The women trainers I admire (including Kelly) always just lift the heaviest they can and they all looked toned and muscular in a good way. So, I've been doing the same and enjoy it. I can feel and see muscle development but when I flex, there is not a lot of definition in my arms. I don't know how to explain it and probably sound dumb but I don't have that "toned" look and maybe it's because my arms are just bigger in general so I kind of think I look more bulky muscle and not sure if I can change that? I see definition in my shoulders but not my biceps. I guess I can attach a picture but then I will really feel goofy! ;)