Predicting maximum acceptable weights of symmetrical and asymmetrical loads for symmetrical and asymmetrical lifting.
Mital-A; Genaidy-AM; Brown-ML
J Saf Res 1989 Mar; 20(1):1-6
A model for predicting maximum acceptable weights of symmetrical and asymmetrical loads for symmetrical and asymmetrical lifting was developed. Eighteen healthy adult males, mean age 22.61 years, experienced in manual lifting activities were studied. Fifteen anthropometric and strength variables were measured for each subject. The subjects lifted five different box sizes and load distributions at rates of 1 to 8 lifts per minute from the floor to a height of 81.3 centimeters (cm) from a height of 81.3cm to 152cm symmetrically or asymmetrically. The maximum acceptable weight of lift was determined for each task. This yielded 60 combinations of four different task variables: lift frequency, lifting height, type of lift, and box size. The data for 12 subjects were used to develop a regression equation that predicted psychophysical lifting capacity in terms of the anthropometric and task variables. The data for the other six subjects were used to verify the model. The equation accounted for 91.6 percent of the variation in the data. Multiplicative factors for adjusting the predicted lifting capacities for inexperienced materials handlers and female workers were obtained from the literature. These indicated that the psychological lifting capacities predicted by the model had to be multiplied by 1.124 to obtain values for industrial male workers and by 0.90 for females. The authors conclude that the proposed model for psychophysical lifting because it deals with asymmetrical lifting is more realistic than other models.
NIOSH-Publication; NIOSH-Grant; Musculoskeletal-system-disorders; Psychophysiology; Materials-handling; Laboratory-testing; Work-capacity; Mathematical-models; Manual-lifting; Humans
Mechanical and Industrial Engr University of Cincinnati Dept of Mec & Indus Engrg Cincinnati, OH 45221
Journal of Safety Research
University of Cincinnati, Cincinnati, Ohio