The effect of wrist rests and forearm support during keyboard and mouse use

Supporting the forearm on the work surface during keyboard operation may increase comfort, decrease muscular load of the neck and shoulders, and decrease the time spent in ulnar deviation. Wrist rests are used widely in the workplace and are more commonly being incorporated in keyboard design. The aim of this study was to examine the effect of wrist rest use on wrist posture during forearm support. A laboratory based, experimental study was conducted (subjects n=15) to examine muscle activity and wrist postures during keyboard and mouse tasks in each of two conditions; wrist rest and no wrist rest. There were no significant differences for right wrist flexion/extension between use of a wrist rest and no wrist rest for keyboard or mouse use. Left wrist extension was significantly higher without a wrist rest than with a wrist rest during keyboard use (df=14; t=2.95; p=0.01; d=0.38). No differences with respect to use of a wrist rest were found for the left or right hand for ulnar deviation for keyboard or mouse use. There were no differences in muscle activity between the test conditions for keyboard use.