Comparison of two methods of sorting recyclable materials on posture among trash sorters in Brazil: a cross-sectional study.

Objective. The aim of the present study was to compare postural exposure between two methods of sorting recyclable materials: manual sorting on a fixed work surface and the use of conveyor belts. Materials and methods. Postures and movements of the head, upper back and upper arms were recorded during 2 h among 40 workers using inclinometers. Sociodemographic variables were collected with the aid of a standardized questionnaire and musculoskeletal symptoms were evaluated using the Nordic musculoskeletal questionnaire. Results. The angular velocity of the head, upper back and upper arms was significantly higher when sorting on a fixed work surface compared to the conveyor belt method. Upper arm elevation was also higher on the fixed work surface. Conclusion. The conveyor belt method showed lower angular velocities during the manual sorting of recyclable materials compared to a fixed work surface.