Which of the following is NOT a structural limitation to movement?

Muscle strength is not classified as a structural limitation to movement because it is more related to the functionality and capability of the muscles rather than a physical attribute that limits mobility. Structural limitations pertain to the physical and anatomical aspects of the body that inherently restrict motion.

The shape of bones, tight skin, and stiff muscles are all physical characteristics that can directly affect the range of motion. The shape of bones can determine the type of joint and the range of movement that can occur at that joint. Tight skin can limit flexibility and the ability of the body to move freely. Stiff muscles can restrict movement as they do not allow for the full range or ease of motion needed for various activities. Therefore, muscle strength, while it can influence performance and movement capabilities, does not reflect a structural limitation in the same way that the other options do.