Ergonomic evaluation of the effects of handle types on garden tools

The objective of this study was to evaluate quantitatively the effects of handle types of garden tools on ergonomic effectiveness, user satisfaction in terms of work performance, and subjective judgment of tactile feel and control. Shoveling performance, hand grip force and electromyography (EMG), task workload, and subjective ratings of perceived exertion were measured while using three types of garden tasks/tools (shovel, rake, and hoe) with three different handle types: a conventional wood handle and two more fiberglass handle. The most effective measure for shovels was the relative efficiency of shovel performance, that is, shovel performance divided by task workload. A hollow fiberglass handle was 12% more efficient than either a wood or solid fiberglass handle. The grip force and EMG analyses showed a similar effect, with a solid or hollow fiberglass handle requiring significantly less effort than a wood handle. Subjective ratings of the perceived exertion were also lowest for a hollow fiberglass handle. A hollow fiberglass handle showed better physiological efficiency and better subjective acceptability for comfort, tactile feel, and decreased slipperiness. Relevance to industry. This research presents a systematic approach to the ergonomic evaluation of new materials on improved work efficiency and user satisfaction. This quantitative examination of grip force, muscular effort, and worker's subjective ratings can be applied to the ergonomic evaluation of other newly developed product. Copyright (C) 1999 Elsevier Science B.V.