Two and Three-Dimensional Biomechanical Torso Models for Pushing and Pulling

Abstract

This paper presents a two and three-dimensional biomechanical torso models for pushing and pulling. The three-dimensional model was developed by dividing the erector spinae and rectus abdominis muscle force components into right and left side and by adding the right and left oblique muscle force components to the two-dimensional model. This paper also presents the results of the muscle forces predicted by the two-dimensional model. The predicted muscle forces were compared with the measured EMG(rms) values (root-mean-square electromyogram values) from the corresponding muscles while pushing and pulling. Three different types of isometric pushing and pulling, namely trunk pushing and pulling, hand pushing and pulling in an erect posture with hips braced and hand pushing and pulling in a free posture at three differrent handle heights were studied. The results show that a simple two-dimensional biomechanical model with only one muscle active at a time may not be appropriate for the estimation of the muscle forces on the lower back.