Effects of load position and force direction on back muscle loading in one-wheeled wheelbarrow tasks

Subtitle:

Article type: Research Article

Authors: Chen, Su-Huang^* | Lee, Yung-Hui | Lin, Chiuhsiang Joe

Affiliations: Department of Industrial Management, National Taiwan University of Science and Technology, Taipei, Taiwan

Correspondence: [*] Corresponding author: Su-Huang Chen, Department of Industrial Management, National Taiwan University of Science and Technology, No. 43 Kee-Lung Road, Sec 4, Taipei 106, Taiwan. E-mail:[email protected]

Abstract: BACKGROUND: Various parameters related to pushing/pulling tasks have been examined yet the effects of changing the load position in one-wheeled wheelbarrow task has not been examined. OBJECTIVE: To explore the effects of load position and force direction on muscle activity during wheelbarrow tasks. PARTICIPANTS: Nine participants were recruited to take part in the experiment. METHODS: Each participant performed 18 trials consisting of 2 force directions (push and pull) and 9 load positions. The dependent variables were EMG of erector spinae and gripping force. ANOVA was used to identify significant differences between force direction and load position in EMG and gripping force data. RESULTS: Results showed that peak EMG was lowest for the left and right erector spinae when the load was positioned farther from the participant. Peak EMG of the bilateral erector spinae increased when the weight was near the participant and on the ipsilateral hand. CONCLUSIONS: Based on the EMG results, we suggest that loads be arranged in the anterior part of the bin in order to reduce muscle activity on the spine during the wheelbarrow task. This finding also provides some directions in the improvement and ergonomic redesign of the one-wheeled wheelbarrow.

Keywords: Push and pull, Electromyography(EMG), MMH, low back

DOI: 10.3233/WOR-141841

Journal: Work, vol. 51, no. 1, pp. 113-119, 2015