Can lost muscle regenerate?
if someone was operated and implanted with a pacemaker, and in this process if the surgeon removed some chest muscles to make space for the pacemaker could that muscle regrow? or is it lost forever?
for example if I got hit with a sword to my lats and a piece of my back has been cut from my body could I regrow that with exercise? or will it be lost muscle that I cannot get back?
It often depends on the extent of the muscle excision. Muscles can undergo hypertrophy, of course, but if a significant portion of a muscle belly is excised, it is common for there to remain at least some loss / visible defect in the area.
This is one of those situations where we’d point out that regardless of the answer to this question – what are you going to do about it? I’d train just as hard either way.