Biomechanical and ergonomics study of manual material handling during team lifting activity

Abstract

This project focused only on the joint contribution and ground reaction force that took place during the team lifting activity made up of two people. This present study hypothesized that the workplace variables such as the weight of loads, the height of load to be lifted and gender would affect the kinetics and kinematics variables. Eight healthy participants (BMI: 18.5 till 24.9 kg/m2) divided into four team where there are two groups of male and two groups of females with two individuals in each team have performed asymmetric lifting task under four different conditions which are two weights of loads (5 kg and 15 kg) and two level of lifting heights (participant knuckle and elbow height from ground). There are five Oqus cameras motion capture system (Pro Reflex infrared, Qualysis) to capture the participant motion, Qualisys Track Manager (QTM) software had been used to label the markers on participant body while the force plate had been used for data collection of ground reaction force throughout the lifting activities. The data collected from QTM converted into C3D file to be used in Visual 3D software to do bone modelling and analysis on ground reaction force, joint angle and joint moment. The results show that here was a statistically significant interaction between the effect on gender and load on joint angle, p=0.001 for hip. However, there is no statistically significant interaction between gender and load on right and left knee angle. Besides the two-way ANOVA was conducted that examine the effect of gender and load on joint moment. Thus, there is a statistically significant interaction between the effect on gender and load on joint angle, p=0.001 for all joint moment at both elbow and knuckle height. In term of ground reaction force, there was a statistically significant interaction effect between gender and load on the combined dependent variable during to-lift phase at in lifting phase position at elbow height and knuckle height, p=0.001 when using two-way MANOVA. Based on the results of this study, it was concluded that hip joint angle, hip and knee joint moment affected by gender and load while for ground reaction force are influenced by the variables of lifting height, lifting stage, gender and weight of loads.