Submuscular or subglandular Breast Implants for a small-chested rock climber?

Subglandular placement gives you an easier recovery but it increases the chance of implant palpability and capsular contracture and it interferes more with mammography. Once healed submuscular placement shouldn't your strength in the long term. Implant displacement may be more of an issue below the muscle though. It is best to discuss your concerns with your plastic surgeon though as he or she has been able to examine you and can give the most accurate advice for your case.

Thank you for the question and pictures.
There are pros and cons to the placement of breast implants and the “sub muscular” position versus the "sub glandular position”.    I will try to outline some of the differences here;  you may find the attached link helpful as well.
I think it is in the best interests of most patients seeking breast augmentation surgery to have implants placed in the “dual plane” or sub muscular position.  This positioning allows for more complete coverage of the breast implants leading to generally more natural feel/look  of the implants in the long-term. This position will also decrease the potential for rippling and/or palpability  of the implants (which may increase with time, weight loss, and/or post-pregnancy changes).

The submuscular positioning  also tends to interfere with mammography less so than breast implants in the sub glandular position. The incidence of breast implant encapsulation (capsular  contraction)  is also decreased with implants placed in the sub muscular position.
On the other hand,  sub glandular breast implant positioning does not have the potential downside of “animation deformity” (movement/ distortion of the breast implants  seen with flexion of the  pectoralis major muscle)  they can be seen with breast implants placed in the sub muscular position.   
Everything considered, the vast majority of patients in my practice (including athletes) undergo breast augmentation surgery with breast implants placed in the sub muscular ( dual plane) position.
Best wishes.