An evaluation of the ergonomics of three computer keyboards

Abstract

The influence of keyboard design on hand position, typing productivity and keyboard preference was evaluated by comparing two segmented alternative designs with the linear standard keyboard. The FIXED alternative keyboard featured a split angle of 12 degrees and a moderate lateral inclination angle of 10 degrees. The adjustable OPEN alternative keyboard was used with a 15 degrees split setting, which resulted in a marked 42 degrees of demiboard lateral inclination. Sixteen typists, who completed 10 h of training on both alternative keyboards, were videotaped while typing set texts on all three keyboards. Forearm and wrist angles based on three-dimensional video analyses were significantly different (p<0.05) among the three designs tested. Both alternative keyboards placed the forearm and wrist closer to neutral positions than did the standard keyboard. While the OPEN keyboard reduced pronation, it simultaneously increased radial deviation. The FIXED keyboard kept the forearm in moderate pronation and the wrist closer to neutral. More time was spent in neutral and moderate ranges of wrist motion when subjects typed on the FIXED compared with the other two designs. With respect to the standard keyboard, typing productivity was reduced by 10% on the FIXED and 20% on the OPEN designs. No significant difference in preference was found between the standard and FIXED keyboards, both of which were preferred over the OPEN. It was concluded that, of the three keyboards evaluated, the FIXED design incorporated moderate changes to the standard keyboard. These changes promoted a more natural hand position while typing thereby reducing the potential for cumulative trauma disorders of the wrist. In addition, the FIXED design preserved a reasonable level of productivity and was well accepted by users.

The effect of six keyboard designs on wrist and forearm postures

“…1). The marker placement was modified from that used by Zecevic et al (2000). Other studies have used electrogoniometers placed across the wrist to measure wrist posture during typing (Honan et al, 1995;Marklin et al, 1999;Simoneau et al, 2003;McLoone et al, 2005).…”

“…The effects of alternative keyboard designs on these postures have been investigated in a number of laboratory studies. The earliest studies measured wrist postures using manual goniometers (Nakaseko et al, 1985), while recent studies use motion analysis systems or electronic goniometers to measure wrist and forearm postures (Honan et al, 1995;Zecevic et al, 2000).…”

Concordance between VDU-users’ ratings of comfort and perceived exertion with experts’ observations of workplace layout and working postures

“…Regarding keyboards, previous cross-sectional studies have concluded that different types of keyboards (i.e. split keyboard, tilted keyboard) have an effect on working postures, productivity, comfort and usability (Marklin and Simoneau, 2004;Woods and Babski-Reeves, 2005;Zecevic et al, 2000). A recently publis longitudinal study has confirmed these results.…”

Effects of a Multitouch Keyboard on Wrist Posture, Typing Performance and Comfort

“…To decrease the incidence of risk, a neutral wrist angle of zero degrees of pronation, extension/flexion and radial/ulnar deviation is hypothesized to be the most favorable wrist posture (Zecevic, Miller, & Harburn, 2000). However, Rempel, Bach, Gordon and Tal (1998) found that minimal carpal tunnel pressure did not occur in a neutral position but at 45° metacarpophalangeal pronation and 2° flexion, which should be taken into account when assessing the design of input devices.…”