Injury Definition a cumulative trauma disorder stemming from prolonged repetitive, forceful, or awkward hand movements resulting in damage to muscles, tendons, and nerves of the neck, shoulder, forearm and hand which can cause pain, weakness, numbness, or impairment of motor control. Some Causes of RSI Repetition. Fine hand movements repeated hour after hour strain muscles and tendons of forearms and fingers, causing microscopic tears. Injured muscles contract, decreasing range of motion. The sheath covering tendons runs out of lubrication, causing tendon and sheath to chafe.
Scar tissue can develop, further limiting range of motion.