I think that you might be misstating the actual mechanics of what is taking place when a charging animal or human is shot. I suppose if you were able to actually shoot the limbs off of a charging dog that this would stop its forward momentum. But in the vast majority of cases what stops any animal which is charging at you is not “breaking the muscles”, it is either destroying the brain with a projectile, or a brain that has been deprived of oxygen by lack of blood flow.
A projectile that destroys the heart or one of the vessels into or out of the heart will do this quickly, otherwise you must hope that the holes you made will cause blood to leak out of the circulatory system quick enough to cause the brain to be deprived of oxygen. Muscles can function without oxygen by anaerobic means for some time, but the brain stops functioning almost immediately without adequate perfusion.
Pit bulls are an easy study in canine muscles. You can see them pretty easily.
Hit a tendon, and that muscle group is down for the count. The dog has a lot more tendons in the chest than humans, and they criss-cross and anchor in areas that are exposed. I’m not talking about “shooting legs off”.