Repetitive strain injury (RSI) is a syndrome in the upper extremities (hands, arms, shoulder and/or neck) and is characterized by sensations of pain, stiffness, fatigue, heat and cold, tingling, numbness, redness of the skin, cramps and loss of fine movement control, eventually leading to general disability. Usually pain, fatigue and stiffness, especially in the neck and shoulder region, are early symptoms, whereas functional loss and disability are mostly seen in advanced states. Initial, temporary episodes of pain and fatigue during repetitive tasks are defined as phase I severity. In phase II the pain has become more persistent and has generalized to other everyday movements. In phase III, pain and functional loss are continuous and unrelated to repetitious movements.

Since symptoms primarily develop in people whose work involves repetitious movements during long shifts, RSI is considered a typical occupational disorder with overuse of upper extremity muscles as a common denominator, although excessive computer gaming has been known to cause RSI complaints as well (‘Nintendo arm’). Alternative terms are ‘occupational overuse syndrome’, ‘work-related upper extremity disorder’ (WRUED) and sometimes ‘focal dystonia’, although the latter term essentially refers to a different, neurological disorder.

Specific and non-specific forms of RSI

RSI complaints generally do not relate to any known biological disorder. Only in a minority of cases (<15%) does standard medical examination reveal tendomyogene or peripheral neuro-conductive abnormalities (Kiesler & Finholt, 1988). To allow a differential diagnosis of specific or non-specific RSI a protocol has been developed with discriminating provocative tests (Sluiter et al., 2001).