The effects of tool handle shape on hand performance, usability and discomfort using masons' trowels

Abstract

The effects of five new different handle shapes on hand performance capabilities, usability and discomfort, and also the relationship between these variables were evaluated in the context of masonry work and using masons' trowels as an exemplar hand tool. The prototype handles were designed to provide different patterns of grip so that they could be suited to the hand/tool interaction in particular hand areas. The results showed significant effect of tool handle shape on the hand grip effort, usability, and hand and finger discomfort assessments, but not on the time to complete the masonry task. The hand grip effort and usability were negatively correlated with subjective assessment of hand and finger discomfort, so that a lower level of hand and finger discomfort corresponded to higher hand grip exertion and usability. These findings provide a better insight into the performance and usability issues when using hand tools which can be applied by tool manufacturers to improve industrial hand tool design. Relevance to industry: These findings present a unique insight into the handle design for industrial hand tool use and support the general conclusion that objective measurements should be supplemented by qualitative subjective assessments to provide a more holistic approach where specific and additional details about the hand tool design characteristics are incorporated from the workers' perspective. (C) 2014 Elsevier B.V. All rights reserved.