A multiple-case study of ergonomics projects aimed at preventing musculoskeletal disorders (MSDs) led us to test whether the use of a model was desirable to ensure sustainable MSD prevention in companies. Once an MSD model incorporating both MSD etiology and the prevention project has been selected, according to the theory of "intermediate object", the use of an MSD model would seem to facilitate discussions among company actors concerned with MSDs. Moreover, the model seems to give them a better understanding of MSDs, which in turn encourages them to make suggestions for adjusting the model to suit their company. After using an MSD model, the authors propose further developments by incorporating both new information about MSD etiology and the adjustments put forward by the company actors.