Can a single-item measure assess physical load at work? An analysis from the GAZEL cohort.

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.