Are there any helpful exercises for toning the area on the back where bra lines are?
To help firm the upper back around the bra line, you need to include aerobic activies in your workout plan. Often this area collects excess body fat, and firming the muscle alone may not get rid of the fat roll you may be noticing.
In addition to aerobics three to five times per week, push-ups would be a good way to work your upper body with just your own body’s weight. Be sure to keep your shoulders rolled away from your ears and lift your chest when doing your push-ups. This will recruit more muscle work in your back.
If you have a gym membership, try using the machines in your weight room that are geared to your upper back. Working your traps and lats would be extremely helpful in tightening up your problem area.
Finally, it is important to remind you that there is no such thing as spot reducing. To lose excess body fat in that part of your back, you may need to pay close attention to your diet and lose overall body weight. Stay away from high fat foods like cakes, cookies, chips, etc. (especially during the holidays). Stick to your workouts and watch what you eat, and you will see results soon!