Musculoskeletal disorders (MSDs) are one of the common causes of work absences, but the majority of affected workers return at the end of three to four weeks. However, in approximately 8% of the cases, the absence lasts longer than 12 weeks. Several studies have attempted to identify the factors explaining prolonged disability, and it is now known that the factor that is associated with MSDs must be considered from a biopsychosocial perspective. For the first time, a study will document, in a context of occupational rehabilitation, the presence and variation over time of the uncertainty-related fears and concerns of workers who have been absent from work for more than 12 weeks due to an MSD. The researchers will use an observational protocol with repeated measures to document the levels of intensity of the components of the subjects’ generalized anxiety and to explore the strength of association of these variables and the biopsychosocial factors of MSDs. The results of this activity will help determine which of these factors should be re-examined in future research.