Which part of the body is not considered a legal blocking zone?

The forearm is not considered a legal blocking zone in roller derby because it does not provide adequate protection to both the blocker and the opponent during gameplay. Legal blocking zones refer to areas of the body that can be used to legally make contact with an opponent without committing a penalty. The chest, thigh, and upper arm are recognized as legitimate parts of the body that can be used for blocking because they help minimize the risk of injury and ensure safer gameplay by allowing for controlled contact. By focusing on these areas, players can effectively navigate the physical nature of the sport while following the rules that promote fair play and safety.