thenammagazine
Super Freak
Regarding the 'peace has cost you your strength' line, while I think you raise good points regarding the toll his body took while being Batman, I interpreted it slightly differently - I think it's as much about peace costing him his strength in the sense that since Batman hasn't been needed, Bruce has been a shut-in and completely out of shape. So he's lost his strength also due to lack of practice and keeping up with his training.
Which was pretty easy to interpret from the film.