For some reason I have been asked several questions geared toward the “bra-line area” over the last few weeks. My first response to that is to ask “how is your diet and cardiovascular training going?” 
Believe it or not, diet and cardio are the most important ingredients in the weight loss and “tone-up” potion. Lifting weights is the third ingredient. But, you need a combination of all three to be successful.
The “bra-line area” consists of a few main muscle groups and I am going to discuss the main two. First, the latissimus dorsi (side of the back or wings) is the main muscle group and pretty much the focus of the exercises below. This muscle is used for just about everything. If you ever go bowling and the muscle close to your arm pit is sore, that’s the latissimus dorsi.
Second, the rhomboids (shoulder blade muscles) play a huge role as well. This muscle is used primarily for retraction or pulling something into your body; a row for example.
I have put together a list of exercises that will help you target this so called “danger zone” and I recommend performing two or three sets of 20 to 30 repetitions along with your normal cardiovascular training. Good Luck!!