I read somewhere that after breaking your muscles apart (f.e. by working out) they start to repair until the muscles reach their new maximum volume/strentgh. All information which is not new for me, ...
Long time ago I used to run in the mornings, workout in the gym 2 days a week, and some martial arts. I was not a gym freak at all but I had some nice definition. Now 8 years later (and 30 years ...