Since I naturally have big arms and I've seen some increase in biceps mass while going to the gym last month, I don't want them to get any bigger, because they are big enough now. But still I want to continue with training them, still working on them and increasing the muscle 'density' but stop gaining muscle mass ? What's the catch, lowering the weight ? So this question is not only about arms, I was always wondering what do I do when I reach my desired size but want to continue training without getting bigger in the process...