Maximum weights of lift acceptable to male and female industrial workers for extended work shifts

Abstract

This paper reports the development of maximum acceptable weight of lift databases for male and female industrial workers for 12-hour work periods. Using a psychophysical methodology, 37 males and 37 females, experienced in manual lifting, performed various lifting tasks involving four frequencies, three box sizes, and three height levels. The maximum acceptable weight of lift was significantly influenced by the frequency of lift, height of lift, and box size. Box size effects were, however, less profound than frequency, and height effects. The maximum weight, acceptable for 12 hours of lifting, elicited an average heart rate of 90 and 101 beats min ⁻¹ for males and females, respectively. Males selected weights that, on average, resulted in metabolic energy expenditure rates of 23% of their aerobic capacity for 12 hours of lifting. Females required metabolic energy expenditure rates equivalent to 24% of their aerobic capacity for lifting acceptable levels of weight for 12 hours.