Repetitive Strain Injury (RSI) is a term used to refer to a group of painful injuries affecting the muscles, tendons and nerves primarily of the hands, arms, neck and shoulders. These injuries are sometimes known as Upper Limb Disorders (ULD) or Work Related Upper Limb Disorders (WRULD).

• Specific named forms - these include Carpal Tunnel Syndrome, Tennis Elbow, Tenosynovitis, Bursitis, etc and are medically identifiable conditions often with noticeable signs such as swelling. There are more than twenty of these disorders of the musculoskeletal system.
• Diffuse RSI - This is where there is no clear-cut diagnosis but a range of symptoms exist. It may also be called Non Specific Pain Syndrome. Recent research attributes this to nerve damage.