The influence of some handle designs and handle height on the strength of the horizontal pulling action

Abstract

The purpose of the present study was to illustrate the effect of the hand-object interface on the ability of a person to exert forces in different postures. Subjects performed one-handed maximal pulling exertions on four different handles, placed 1·0m and 1·75 m above the ground. The strength of manual exertion was significantly affected by handle type (p<0·0l) and handle placement (p<0·01). Analysis of variance also indicated a significant interaction between handle type and handle position (p>0·01). Handles with the largest degree of hand-handle contact and those which permitted a power grip to be deployed, enabled the largest pulling forces to be produced. Under these conditions, force output was highly dependent on handle placement. However, placement of handles with poor hand-handle interfaces had little effect on maximal pulling strength. The inference that the hand-handle interface is the 'weak link1 in force transmission when intense pulling exertions are executed on poorly-designed handles has important implications for the design of manual handling tasks.

Keywords:

• Pulling strength
• Handle design
• Handle placement
• Isometrics