Asundi Krishna, Odell Dan
Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.
Work. 2011;39(2):151-9. doi: 10.3233/WOR-2011-1161.
This article aims to provide designers and researchers with a summary of the current literature regarding the effects of specific keyswitch design parameters on user preference, performance, and biomechanical outcomes.
Studies which evaluated the effects of keyswitch make force, make travel and over travel on preference, typing speed, errors, keyboard reaction forces and upper extremity EMG are included in the review. Studies which examined possible control strategies employed during keyswitch tapping are also covered.
General conclusions that can be drawn from these studies are: greater make forces result in increased keyboard reaction forces and EMG activity, users strike keys with forces 2-7 times the required make force and that they employ a ballistic finger motion to do so. Furthermore, typists tend to prefer kinesthetic and auditory feedback.
Due to the ballistic nature of typing, new keyswitch designs should be aimed at reducing impact forces. Future studies should examine the role of breakaway force and over travel as limited research has been done on the role of these parameters.
