Affiliations: Institute of Ergonomics, Department of Mechanical
Engineering, Darmstadt University of Technology, Darmstadt, Germany | Department of Industrial Engineering, National Tsing
Hua University, Hsinchu, Taiwan
Note: [] Address for correspondence: M. Diaz-Zeledon, Institute of
Ergonomics, Darmstadt University of Technology, Petersenstrasse 30, Darmstadt
64287, Germany. E-mail: diaz@iad.tu-darmstadt.de
Abstract: The objective of this study is to investigate the effect of the
variations of an objects' instability, on the upper body and trunk locomotion
system during self-paced, 3D, and reaching and transport movements performed in
a seated position. Unstable objects can be found in many industrial sectors,
such as chemical industries or service areas. Due to the deficit in methods of
their manipulations and investigations of the related effects has motivated the
present study. 30 subjects (15 male, 15 female) participated in this
experiment. The physical human responses were measured using (a) self-paced
Hand Motion Time, (b) Range of Motion of the trunk, shoulder, and elbow, (c)
muscular strain of selected muscle groups in the shoulder, arm, and trunk. The
mental workload is measured by subjective assessment, of the unstable moved
object. The results of the statistical tests prove that there is an effect of
the liquid level and target position on the physical and mental level of the
locomotion system. Direction of movement (motion-phase) presents a significant
influence on the Range of Motion, the muscular activity and the Hand Motion
Time. These results can be applied to evaluate, and develop products for
workplaces, where the reduction of musculoskeletal injuries plays an important
role.
Keywords: Motion-analysis, unstable objects, workplace design, muscular strain, hand motion time, range of motion
