The effect of three alternative keyboard designs on forearm pronation, wrist extension, and ulnar deviation: a meta-analysis

Am J Occup Ther. 2006 Jan-Feb;60(1):40-9. doi: 10.5014/ajot.60.1.40.

Abstract

The growth of computer keyboard use in the workplace is believed to be one important determinant of the increased prevalence of work-related musculoskeletal disorders of the upper extremity (MSD-UE). One possible contributing factor to the development of MSD-UE is the flat standard keyboard, which places the forearm and wrist in biomechanically awkward postures. This meta-analysis examines the efficacy of three alternative keyboard designs, adjustable slope (AS), split fixed-angle (FA), and adjustable open-tented (AT), in reducing forearm pronation, wrist extension, and ulnar deviation. Analyses of pooled effect size from six studies indicated that the AT had a large effect on pronation (r= 0.85) and ulnar deviation whereas the FA had a large effect only on ulnar deviation (r= 0.79). The AS was found to have a large effect (r= 0.66) on wrist extension. The FA had a moderate effect on pronation (r= 0.33) and wrist extension (r= 0.30). None of these keyboards were found to have a significant effect on all three postures. This meta-analysis has implications for clinicians by providing objective information that may assist with the selection of an alternative keyboard that best reduces an identified problematic posture.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomechanical Phenomena
  • Clinical Trials as Topic
  • Computer Peripherals*
  • Cumulative Trauma Disorders / prevention & control*
  • Equipment Design*
  • Ergonomics*
  • Forearm / physiology
  • Humans
  • Occupational Diseases / prevention & control
  • Posture / physiology
  • Pronation / physiology
  • Ulna / physiology
  • Upper Extremity / physiology*
  • Wrist / physiology