What is a joint sprain primarily caused by?

A joint sprain is primarily caused by traumatic twisting, which typically occurs when a joint is forced into an unnatural and unstable position. The twisting motion places excessive stress on the ligaments that support the joint, leading to their overstretching or tearing. This type of injury is common during activities that involve sudden changes in direction, awkward landings, or falls.

The other options might lead to different types of injuries or conditions. Impact force generally refers to direct blows or collisions that can cause bruises or fractures, while overextension may result in strains rather than sprains, especially if the muscles or tendons are involved. Friction during movement can lead to chronic issues like tendonitis, but it is not a primary cause of sprains. Thus, traumatic twisting is the most accurate description of how joint sprains occur.