The negative aspect of arm strength is when the arm itself becomes the primary mechanism to throw the baseball. This can also be described as “disconnection.” Disconnection means the arm has lost its ability to receive/transform momentum from the body. A consequence of this disconnection forces the arm-shoulder complex to become more active than it should in terms of throwing a baseball. The player is trying to make up for the lack of efficient transfer of momentum by “muscling” the ball to the plate.
This is a tremendously great article that you HAVE to read. There are a lot of animations involved.