Effect of Anthropometry on Maximum Acceptable Weight of Lift

Abstract

Manual material handling (MMH) and lifting activities are believed to contribute to the risk of low back pain (LBP). It has been found that as many as 50% of all back pains may be related to manual lifting activities. Revised NIOSH lifting equation (RNLE) was designed to reduce the incidence of LBP by recommending safe load limits, called the recommended load limit (RWL). While, an effect of worker characteristics like age, gender, weight and ethnicity, on load lifting task has been seen, the RNLE considers the effect of task demands only for establishing the RWLs. Thus, the present study investigates the role of worker anthropometry in a manual lifting task. The findings have been discussed in the light of the RNLE. A psychophysical methodology was adopted to arrive at the maximum acceptable weight limits (MAWLs). 50 industrial workers (25 males and 25 females) participated in the study. ANCOVA for gender using acromial height and wrist circumference as covariates showed that while acromial height and wrist circumference had a statistically significant effect on MAWL, gender did not. Further, it was observed that the using psychophysical criteria of 75% capable females (as per the RNLE guidelines), resulted in a MAWL of 22.2. kgs, which is comparable to the recommended weight limit (RWL) of 23 kg as obtained by the RNLE.