2. MATERIALS AND METHODS
2.1. Examined Population
This cross-sectional study was conducted from August to December 2007 among the production workshops of an Iranian sugar-producing factory. This plant employed 700 male workers, divided into three shifts and four groups. One hundred
and sixteen workers with at least one-year job tenure were randomly selected for this study. Workers with background diseases or accidents affecting their musculoskeletal system were excluded from this study