Comparing Upper Arm and Back Postural Exposures between Apple Harvesting with Ladders and Mobile Platform

Abstract

In the US tree fruit industry, in attempt to improve the efficiency of orchard workers; harvest-assisting mobile platforms have been introduced. However, the effect these mobile platforms have on physical exposures, i.e. non-neutral work postures, has not been evaluated. The purposes of this study were to compare ergonomic risk factors between a new apple harvesting method using mobile platforms and the traditional method using ladders. Twenty-four workers participated in this study and were equally divided into three groups, harvesting apples from ladders (n = 8), mobile platforms (n = 8) and the ground (n = 8). Upper arm and back inclinations were continuously monitored and calculated over the whole work period, excluding breaks. Upper arm posture was characterized in terms of the percent of time when upper arm flexion and abduction exceeded 30, 40, 50, 60, 70 80 and 90 degrees. Back inclination was characterized as the percent time forward bending exceeded 10, 20 and 30 degrees. The results showed that the workers on the mobile platform typically had lower postural exposures than the ground and the ladder workers, respectively.