Validity of a self-administered questionnaire for assessing physical work loads in a general population

The aim of the study was to evaluate eight questions concerning physical loads, used in public health questionnaires. Working women and men (203) completed a self-administered questionnaire twice, following a test-retest method. The questions were also validated with a structured interview. Response agreement was calculated with Cohen's kappa-statistics with quadratic weights (kappa(w)). Test-retest agreement varied from 0. 74 to 0.92, and inter-method agreement from 0.38 to 0.81. The lowest coefficients were for the questions concerning bent/twisted work postures (kappa(w) 0.38) and repetitive movements (kappa(w) 0.39). The results did not indicate any substantial influence of gender, type of work or musculoskeletal complaint. The questions concerning general physical activity and sitting work postures, and physical exercise/sports during Leisure times, had good validity. The questions concerning bent/twisted work posture and repetitive movements need to be re-designed.