Can a single-item measure assess physical load at work? An analysis from the GAZEL cohort.: Validity of a work-related physical strain measure

Abstract : OBJECTIVE: The assessment of workplace physical load is highly resource intensive. This study tested whether a single-item measure asking individuals about perceived physical strain (PPS) at work was an acceptable proxy for physical load. METHODS: The study was conducted in a subset of the GAZEL cohort (n = 2612) undergoing assessment of exposure to 38 occupational biomechanical constraints (representing eight domains) in 1994. Test-retest reliability analyses compared PPS in 1994 and 1995. Validity analyses compared PPS in 1994 to concurrent strains assessed in the more extensive measure. RESULTS: The measure showed adequate test-retest reliability. Within and across domains of physical load, linear relationships (P < 0.0001) existed between n exposures and PPS. Domains considered more strenuous (carrying loads, pulling objects) showed the highest PPS. CONCLUSIONS: Perceived physical strain approximates physical load in the absence of detailed measures. Perceived physical strain could be used in nonoccupational epidemiologic studies.