Patterns of differences between the maximum weights of lift acceptable to experienced and inexperienced materials handlers

Abstract

Maximum acceptable weight of lift (MAL) data were collected on 74 inexperienced students and compared with data previously collected for 74 experienced (industrial) materials handlers under identical experimental conditions to determine the patterns of differences in the MAL of the two groups. The results revealed that while students and industrial workers did not differ significantly in their physique and isometric strength exertion capabilities, there were statistically significant differences in the weights the two groups were willing to lift for regular 8 h shifts. Male students, on the average accepted 11% less weight than industrial males; female students accepted 6% less weight than industrial females. For 12 h shifts, the MAL differences between the two groups narrowed down to within 2%. The reductions in MAL with lifting frequency, box size, and lifting height for inexperienced and experienced workers were found to be similar. When the psychophysical methodology is used, inexperienced students tend to underestimate their MAL less than industrial workers.

Keywords:

• Psychophysical approach
• Isometric strengths
• Maximum acceptable weight of lift