Musculoskeletal disorders (MSDs) are universally prevalent among all age and gender groups and across all socio-demographic strata of society. Besides causing pain and decreased functional capacity, MSDs have a substantial influence on work capacity and quality of life. Altogether, they inflict an enormous financial burden on society through direct medical costs as well as indirect costs due to loss of productivity and social security benefits. The yearly burden of disease in the Netherlands for the two most important groups of MSDs, low back pain (LBP) and neck and upper extremity complaints, is over € 5.500 million. The majority of MSDs fall into the category of nonspecific disorders. Often these nonspecific disorders are related to overload, deconditioning or workrelated overexertion. Although much research has been performed, especially with regard to LBP, knowledge about the long-term pain patterns or predictors over the life course is limited. For many possible prognostic indicators, especially regarding the psychosocial domain, consistent evidence is lacking. Early identification of patients more likely to develop persistent symptoms could help to guide decisions regarding medical management. However, optimal management strategies, including attention for psychological and workrelated factors, are still unclear. In this thesis several studies are brought together about the course, prognosis and management of LBP and neck and upper extremity complaints. Together, these studies provide insight into the possibilities to identify subgroups of patients through the assessment of non-medical criteria, especially within the category of nonspecific complaints. These subgroups might profit from a different approach in treatment or guidance.