Postural Analysis on Manual Pine Resin Collecting Work: Lifting Index and L5/S1 Compression-Shear Forces

Abstract

Even though pine oleoresin harvesting is labor-intensive forestry work involving manual material handling (especially lifting) and is massively carried out in Indonesia, there is a lack of ergonomics studies on manual pine oleoresin harvesting. This study focused on lifting-related postures in pine oleoresin harvesting. A Three Dimension Static Strength Prediction Program Version 7.1.0 was used to identify the injury risk on the lower back (lumbosacral joint, L5/S1) using biomechanical criteria (compression and shear forces) at extreme postures. Recommended Weight Limit (RWL) and Lifting Index (LI) were calculated for a comprehensive analysis. The exceeding compression and shear forces indicated that the L5/S1 injury risk on oleoresin collecting work (part of oleoresin harvesting) is high. The psychophysical analysis confirmed the findings, as several main postures in this work were categorized as intense manual lifting due to the excessive score of LI. A significant reduction in the L5/S1 compression and shear forces were shown at a simulation using a proposed load threshold (using the calculated RWL). Keywords: biomechanics, ergonomics, forestry work, manual lifting, oleoresin harvesting