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

Abstract

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 ¼ 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 ¼ 2:95; p ¼ 0:01; d ¼ 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. Relevance to industryWrist rests are used widely in the workplace and are more commonly being incorporated in keyboard design. Use of a wrist rest in conjunction with forearm support when using a conventional desk does not appear to have any impact on wrist posture or muscle activity during keyboard use. r

The impact of computer display height and desk design on muscle activity during information technology work by young adults

“…In contrast Cook et al (2004a) found a reduction in UT and anterior deltoid activity with forearm support provided by a straight desk (as well as with wrist support provided by a wrist rest) compared to a free floating arm position during keying. However, their other study (Cook et al, 2004b) found no differences between free floating and wrist rest conditions for both keying and mouse use tasks. One possible reason for the conflicting results could be the extent to which participants actually used the support provided and the nature of the support they gained (full forearm support or only wrist support).…”

The Importance of Work Environment Facilities

“…The ergonomic chair shall be stable and allow the user moves easily and sits in a comfortable position. The ergonomic chair will affect the workers performance through minimization of fatigue and stress (Cook et al, 2004). Therefore it is a crucial decision should be taken by an organization by providing the workers with ergonomic chair.…”

A Comparison of Muscular Activity Involved in the Use of Two Different Types of Computer Mouse

“…The skin was cleaned and shaved; alcohol was used to remove dirt, oil and dead skin. The electrodes were placed over the horizontal fibres of the middle trapezius, a quarter of the distance from the acromion to the 7th cervical vertebra (C7) [2]; the ground electrode was placed on C7 [16]. The electrodes for the anterior deltoid were placed over the belly of the muscle 6 mm apart [2]; the ground electrode was placed on the acromion [16].…”

“…A computer mouse is associated with most software applications requiring movement of a screen cursor [2]. It appears that computer users spend two thirds of their computer work hours using a mouse [3].…”

“…Postures adopted while using a mouse are shoulder abduction, forward flexion of shoulder and external rotation [7,8,9]. The abduction of the arm has been shown as a risk factor for musculoskeletal disorders of the neck and shoulder [2]. Mouse users have reported adopting postures of extension, pronation and ulnar deviation of the wrist [3,8,10].…”