Industrial wrist motions and incidence of hand/wrist cumulative trauma disorders.
Schoenmarklin RW; Marras WS; Leurgans SE
Ergonomics 1994 Sep; 37(9):1449-1459
A quantification of known kinematic risk factors for hand/wrist cumulative trauma disorders (CTD) in industrial jobs and their incidence was investigated. Forty industrial workers aged 25 to 62 years (22 males, 18 females) employed at eight industrial facilities in the United States Midwest area were monitored. The minimum acceptable number of fundamental wrist movements for eligibility was 13,000 during an 8 hour shift. Wrist motion and forearm rotation were measured by a wrist monitor and a pronation/supination device, respectively. The experimental protocol consisted of at least ten trials lasting 10 seconds each for each worker at a normal job pace. Kinematic data were analyzed using discriminant function analysis and multiple logistic regression. Results showed that average peak flexion/extension (flex/ext) acceleration predicted CTD incidence rate better than any other variable, with odds ratios (OR) of 6.05 and 5.03, respectively. The second best predictor was flex/ext average velocity and radius/ulna acceleration, with ORs of 3.8 and 3.3, respectively. Position values predicted CTD poorly (OR 1.23 to 1.52). Acceleration in the flex/ext plane was the strongest predictor of groups of low and high CTD incidence rate. The 75th percentile peak acceleration from the high incidence (HI) group was greater than all but a few of the peak accelerations from the low incidence (LI) group. Above the 75th percentile level, there was a 98% probability that the job had a HI of CTD. At peak acceleration less than the 50th percentile, there was about a 67% probability than the job had a LI of CTD. The authors conclude that the relative risks for repetitive jobs that do not use hand tools can be worked out using the values from this study. The authors recommend that the methodology be used for ergonomic assessments.
NIOSH-Publication; NIOSH-Grant; Musculoskeletal-system-disorders; Carpal-tunnel-syndrome; Ergonomics; Hand-injuries; Mathematical-models; Cumulative-trauma-disorders; Occupational-hazards; Repetitive-work; Risk-analysis
Industrial and Systems Engr Ohio State University 1971 Neil Avenue Columbus, Ohio 43210
Ohio State University, Columbus, Ohio