[Musculoskeletal disorders of upper extremities caused by biomechanical overload: methods and criteria for the description of occupational exposure].

This article presents and discusses a model for describing and evaluating the principal risk factors characterising occupational exposure: frequency and repetitiveness of movements, use of force, type of posture and movements, distribution of recovery periods, presence of other influential (complementary) factors. For each risk factor, the authors propose a method of practical detection in the field, as well as criteria for classifying and interpreting the results based on a critical review of the available literature on the subject. Numerous examples are supplied to better illustrate the concepts presented. The various factors considered are classified using numbers or indexes, so that they can be integrated into a concise exposure index described by the authors elsewhere in this volume.