An investigation into the biomechanical characteristics and physiological cost of three standardized pulling tasks

Handrigan, Grant (2008) An investigation into the biomechanical characteristics and physiological cost of three standardized pulling tasks. Masters thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (3MB)

Abstract

The purpose of this study is to measure energy expenditure and trunk kinematics while performing three standardized pulling tasks. It is hypothesized that as the height of pulling increases (handle height) energy expenditure and trunk kinematics will change to reflect this. In order to accomplish this research twelve female and seventeen male subjects from a university aged population participated in the study. The subjects were instructed to pull at three heights (hip, shoulder, eye) at a rate of ten pulls per minute, for a period of 10 minutes (one hundred total pulls). The load was fixed at 15% of the subject's absolute body mass. Based on previous research, subjects were instructed to assume a standardized fixed foot position. This was performed in order to control the foot positioning while performing the pulling task. Statistics . The data set was verified to satisfy assumptions inherent with a repeated measures analysis of variance (ANOVA). Where main effects existed, a Bonferroni pairwise comparison was performed to determine significance. Results . Statistical significance was obtained for energy expenditure, sagittal displacement and twisting velocity. Hip pulling energy expenditure was lower than shoulder and eye pulling energy expenditure (7% and 11%, respectively, p< 0.05). Finally, twisting velocity at hip and shoulder pulling were 30% and 36% (p< 0.05) than twisting velocity at eye pulling. Hip pulling involves less sagittal displacement than shoulder (p=.004) and eye (p=0.001) by 37% and 46%, respectively. Conclusion . Physiological data indicate that all three heights of pulling are characterized as 'light' work and a slight increase in energy expenditure was apparent as the pulling height increased. This change in trunk kinematic movement strategies from a predominantly twisting motion at hip height to a forward/backward flexion at eye height leads to an increase in energy expenditure in inexperienced individuals.

Actions (login required)

View Item