When a muscle contracts, but not all the muscle fibers are activated, what happens to the remaining muscle fibers?
I don't think the unused sacromeres will contract though because every time you contract, it requires ATP and so it will be really expensive if you contract when you don't need to. I believe the unused muscle fibre will just be compressed or bent, since cells have a certain degree of compliance. I am guessing that is also why you won't feel your muscle as hard if you are not doing MVC