Affiliations: Ergonomics Division, University of Siegen, Siegen, Germany
Correspondence:
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Corresponding author: Mario Penzkofer, Department of Mechanical Engineering, Ergonomics Division, University of Siegen, Paul-Bonatz-Str 9-11, D-57068 Siegen, Germany. Tel.: +49 2717402251; Fax: +49 2717402740; E-mail:penzkofer@ergonomie.uni-siegen.de
Abstract:
BACKGROUND: Screwdrivers are a standard tool in all metal and wood
processing jobs. To prevent work-related injuries in the upper extremities, an ergonomic and
safe design of the tool is indispensable. OBJECTIVE: In this comparative ergonomic study, the ergonomic
quality of various screwdriver handles from European manufacturers, which
exhibited decisive differences in the design aspects ``shape'',
``dimension'', ``material'' and ``surface'', was tested. METHODS: Twenty-one male right-handed test subjects had to carry
out different screw-driving tests. Before and after the tests, the subjects
had to assess specific criteria of the handles such as handling, design
features and material. Furthermore, they were asked to express potential
physical complaints in the fingers, hand and forearm with respect to
intensity and occurrence. In order to reveal possible model-specific
differences in operational performance and in muscle strain, maximum
exertable torque measurements were carried out, and the associated
electromyographic activity (EA) of four muscles involved in different
screw-driving tasks was measured via surface electromyography. RESULTS: The results from the determined EA data and the users'
subjective perceptions while handling the screwdrivers, showed a great
impact of the design features ``shape'', ``dimensions'', ``material'' and
``surface''. CONCLUSIONS: Only those screwdrivers designed according to
appropriate ergonomic criteria enable a high operational performance with
reduced physiological costs that have to be paid by the muscles.
