Effects of a vertical keyboard design on typing performance, user comfort and muscle tension

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.apergo.2005.09.005 Byline: Gerard P. van Galen, Hanneke Liesker, Ab de Haan Keywords: Keyboard design; Repetitive strain injury; Muscle tension Abstract: To circumvent the awkward pronated hand position inherent to conventional horizontal keyboards, a vertical, split keyboard was designed with flexible cushions supporting the wrists, allowing relaxed hand and arm postures. During eight twice-weekly 30-min training sessions, the performance and subjective comfort of nine experienced typists were tested. Typing speed and error percentage, and surface electromyographic activity of six forearm muscles and two postural muscles were recorded in separate sessions at the end of each week. Typing speed rapidly recovered to the preset rate of 300 keystrokes/min and error percentages were similar for the two keyboards. The vertical keyboard caused lower muscular activity in especially finger extensor muscles, did not increase postural muscle activity, and self-reported comfort was higher. Thus, the vertical keyboard was easily mastered, was experienced as comfortable, and caused less stress on muscles sensitive to repetitive strain injuries. Author Affiliation: Radboud University Nijmegen, P.O. Box 9104, NL 6500 HE Nijmegen, The Netherlands Article History: Received 4 November 2004; Accepted 27 September 2005