Wrist and Forearm Postures of Users of Conventional Computer Keyboards

Document Type

Article

Language

eng

Format of Original

12 p.

Publication Date

9-1999

Publisher

Human Factors and Ergonomics Society

Source Publication

Human Factors: The Journal of the Human Factors and Ergonomics Society

Source ISSN

0018-7208

Original Item ID

doi: 10.1518/001872099779610978

Abstract

The aim of this study was to perform a comprehensive investigation to document wrist and forearm postures of users of conventional computer keyboards. We instrumented 90 healthy, experienced clerical workers with electromechanical goniometers to measure wrist and forearm position and range of motion for both upper extremities while typing. For an alphabetic typing task, the left wrist showed significantly greater (p < .01) mean ulnar deviation (15.0° ± 7.7°) and extension (21.2° ± 8.8°) than the right wrist (10.1° ± 7.2° and 17.0° ± 7.4° for ulnar deviation and extension, respectively). Conversely, the right forearm had greater mean pronation (65.6° ± 8.3°) than the left forearm (62.2° ± 10.6°). We noted minimal functional differences in the postures of the wrists and forearms between alphabetic and alphanumeric typing tasks. Ergonomists should consider the statistically significant and probable practical difference in wrist and forearm posture between the left and right hand in ergonomic interventions in the office and in the design of computer keyboards. Actual or potential applications of this research include guiding the design of new computer keyboards.

Comments

Human Factors: The Journal of the Human Factors and Ergonomics Society, Vol. 41, No. 3 (September, 1999): 413-424. DOI: 10.1518/001872099779610978.

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