Lean Job Design and Musculoskeletal Disorder Risk: A Two Plant Comparison

This study examined the relationship between lean job design and work-related musculoskeletal disorder (WMSD) risk factors. Repetition, force, and posture were assessed for a sample of 56 production jobs across departments at a lean automobile-manufacturing plant and compared to 56 similar jobs at a traditional automobile-manufacturing plant. The results showed greater productivity in the lean plant: less waiting (p = .006) and walking (p < .001); and greater repetition exposure (p = .001). The mean rating for repetition was 5.5 in the lean plant, compared to 5.0 in the traditional plant based on the Latko (1997) hand activity level scale. However, the lean plant had significantly lower peak hand force ratings (p = .01). When examining force and repetition combined, the lean plant had a lower percentage of jobs above the American Conference for Governmental Industrial Hygienists (ACGIH)-recommended Threshold Limit Value (TLV (R)). The findings suggest that lean manufacturing does not necessarily increase workers' risk for WMSD injuries. (c) 2009 Wiley Periodicals, Inc.