Other questions want to know how to train for isometric strength. I want to know what is physiologically different about a person who can hold static weights vs. a person who can lift heavy weights in a full range of motion.
While doing one type of exercise clearly helps in the other, there are people who are clearly stronger in one over the other.
Arm wrestlers tell me that their incredible static strength comes from stronger tendons. This doesn't make sense to me, since tendons are only a part of the chain. I believe there must be something different in the musculature, but aside from bigger muscles I have no idea how. One of the answers to this quetion says
Isometric contraction work outs major downfall is they only train the range of motion you are using (90º for example). This means if you wanted to have the same "grocery lifting" strength anywhere else in your range of motion you would have to move to that angle and train that portion (45º). You would then be less strong at all other angles than 45º and 90º.
So somehow the muscle is stronger at different levels of contraction. Clearly something more is happening here than just bulkier muscles, or else different angles wouldn't affect it. What is happening, then?