Title: Fractional factorial analysis of lifting and carrying tasks on postural score to investigate the effect of contributing parameters and their interactions

Authors: Ajay Batish, Anirban Bhattacharya, Prasant Maddamsetty

Addresses: Mechanical Engineering Department, Thapar University, Patiala 147004, Punjab, India. ' Mechanical Engineering Department, Thapar University, Patiala 147004, Punjab, India. ' Design and Engineering Section, Voith Turbo Pvt. Ltd., Hyderabad, India

Abstract: This laboratory experiment examines the effect of four lifting and carrying task parameters: load weight; lifting frequency; vertical lifting distance; and obstructions en route and their interactions on the posture score measured using the rapid upper limb assessment (RULA) methodology. In this simulation study, four shop floor workers lifted weights in 27 different combinations of lifting parameters, in which three different levels of lifting frequencies, load weights, vertical lifting heights and obstructions en route were considered. The subjects did symmetric lifting for 30 minutes period. Analysis of variance result showed that other than obstructions en route, the remaining main effects were significantly related with posture score measured using RULA methodology. Also, the interaction between the load weight and frequency of lift were significant for some of the subjects. The worker stress level varies from individual to individual when looked at separately for four different subjects. The loads to be placed at shoulder height are most stressful and should be avoided as far as possible. The results for posture scores show that lifting load from the floor level with high frequency of lift is the most stressful task.

Keywords: lifting tasks; carrying tasks; RULA; rapid upper limb assessment; fractional factorial analysis; postural scores; contributing parameters; load weights; lifting frequencies; vertical lifting distances; obstructions; posture; shop floor workers; weights; heights; symmetric lifting; worker stress levels; shoulders; ergonomics; manual handling; materials handling; India; human factors.

DOI: 10.1504/IJISE.2010.035014

International Journal of Industrial and Systems Engineering, 2010 Vol.6 No.3, pp.301 - 320

Available online: 01 Sep 2010 *

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