Shoulder Disorders: NIOSH (1997) identified over twenty epidemiologic studies investigating shoulder musculoskeletal disorders. Evidence of association between repetition and shoulder disorders was identified. Few studies investigatedactual repetitive neck movements. There is also evidence of association between a combination of risk factors; repeated or sustained exertions and elevated shoulder postures (>60 degrees of flexion or abduction) and shoulder disorders.There is insufficient evidence for an association between force and shoulder MSDs. The evidence for specific shoulder postures is strongest where there is combined exposure to several physical factors, such as holding a tool while working overhead.