Hi Diamond
The decision to go over and under when having breast augmentation can be a very difficult one especially in women who are fitness instructors or do fitness modelling.
Here's why:- fitness women are generally very lean with no subcutaneous body fat, therefore placing an implant above the muscle, especially such a large implant as you desire (500-550cc) leads to the implant being palpable and visible especially the upper edge. Which is undesirable.
- To camouflage the upper pole of the implant it is advisable to go below the muscle, however this then becomes an issue in your case because you work out alot and have strong pec muscle. This can lead to animation of the implant and rotation of the implant.