The positional support structure of the
fat sex doll hides risks. Biomechanical experts point out that although the titanium alloy skeleton commonly used in the
American sex doll is light, if its joint movement angle exceeds ergonomic standards, it may cause muscle strain from the user. A lawsuit revealed that a brand caused chronic damage to the iliopsoas muscle of 23% of users due to arbitrarily modifying the curvature of the knee joint. When purchasing, you should focus on checking whether the product complies with the ASTM F3180-17 position auxiliary equipment specification. This standard is specially formulated for the biomechanical safety of the American sex dolls.