Affiliations: Department of Environmental Health, Harvard School of
Public Health, Boston, MA, USA | Microsoft Hardware Corporation, Redmond, WA, USA
Note: [] Address for correspondence: Krishna Asundi, Ph.D., Department of
Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.
Tel.: +1 617 384 8768; Fax: +1 617 384 8767; E-mail: kasundi@gmail.com
Abstract: Objective: 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. Methods: 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. Results: 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. Conclusions: 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.
Keywords: Typing force, human computer interaction, biomechanics
