Final answer:
Pain occurs with active motion of the extremity.
Step-by-step explanation:
Pain occurs with active motion of the extremity. In other words, when you move the extremity, such as your arm or leg, and feel pain, it is usually associated with an active movement. For example, if you have a fracture in your arm and you try to lift something heavy, the pain will likely increase or be felt when you make the movement. This is because when you actively move the injured extremity, it puts stress on the affected area and can trigger pain.