[Connections between musculoskeletal complaints and personality]

Modern research has demonstrated a weak association between level of muscle tension and experience of muscle pain. Anxiety and dysphoric over-responsiveness are the traditional psychogenic risk factors in muscle tension. Results from recent Norwegian research lend support to a more multidimensional causal understanding of muscle tension and of pain. Generally, personality factors were found to be a contributory cause of muscle pain of the neck and shoulders, whereas ergonomic load was found to be of greater significance for low back pain. Personality factors may induce patterns of skeletal muscle activation discrepant with characteristics of the skeletal muscle physiology: Preference for aerobic activities may develop through social learning, whereas the muscles may be genetically biased toward anaerobic activities. Furthermore, personality factors may be challenged by the work setting, and may result in mismatch that provokes muscle pain. Impatient expenditure of effort has appeared as a mediating personality risk factor among workers exposed to high ergonomic load, whereas dysphoric over-responsiveness mediated back pain primarily among staff exposed to high emotional load.