Wrist and Forearm Postures of Users of Conventional Computer Keyboards

Simoneau, Guy G.; Marklin, Richard W.; Monroe, John F.

doi:10.1518/001872099779610978

Cited by 42 publications

(41 citation statements)

References 16 publications

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“…This angle is higher than that obtained in the laboratory by Serina et al (1999), which was -20°, and by Simoneau et al (1999), which was -17°, but in both these experiments the operators had furniture that could be adapted to their morphology, which was not the case in the present study. The average angle of the wrist in the cubital-radial plane was higher in CAD than in data entry with keyboard use.…”

Section: Discussioncontrasting

confidence: 88%

“…In terms of the wrists, the distance of the keyboard, even if excessive in data entry, undoubtedly allows better hand-forearm alignment. It should also be pointed out that the average angle obtained in CAD was identical to that measured by Simoneau et al (1999), which was 10° in an alphabetic typing tasks. The average abduction-adduction angle of the shoulder when using the keyboard did not differ between CAD and data entry, but this angle was higher than 20° in both tasks.…”

Section: Discussionsupporting

confidence: 68%

“…), work organisation, psychosocial factors, and stress, but also biomechanical stresses, which encompass the forces, the angles of the joints, and the repetitiveness of movements (Malchaire, Vergracht, & Cock, 2000;Punnett & Bergqvist, 1997). These biomechanical stresses are however often studied in the laboratory (Serina, Tal, & Rempel, 1999;Simoneau, Marklin, & Monroe, 1999) and rarely in the field. In addition, these studies often examine only one joint and do not always include the collection of subjective data.…”

Section: Introductionmentioning

confidence: 99%

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Biomechanical Stresses in Computer-Aided Design and in Data Entry

Cail

Aptel

2003

International Journal of Occupational Safety and Ergonomics

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A study of the risk factors of musculoskeletal disorders (MSDs) of the upper limbs was carried out on 2 populations, 1 performing a computer-aided design (CAD) task and the other performing a data entry task. A questionnaire on MSD complaints and working life was completed by a sample of each population. Biomechanical measurements of the forces, the angles, and the repetitiveness of movements of the upper limbs were carried out on some operators in each sample. It emerged that complaints of the upper limbs seem to be linked to the use of input devices. The grip forces exerted when using the keyboard and mouse were higher in CAD than in data entry.VDU work MSD biomechanical stresses INTRODUCTIONPostural problems caused by working with computer display screens have been highlighted in numerous epidemiological surveys (Punnett & Bergqvist, 1997). The parts of the body concerned are primarily the neck, the shoulders, the lower back, and increasingly the upper limbs. Among these operators, the occurrence of upper-limb musculoskeletal disorders (MSDs) has been increasing rapidly since the end of the 1980s, particularly in the USA. It more than doubled each year in this country from 1988 to 1992 and continuedCorrespondence and requests for offprints should be sent to François Cail, Institut National de Recherche et de Sécurité, Avenue de Bourgogne, B.P. 27, F-54501 Vandoeuvre Cedex, France. E-mail: .( %#+. #0& / #26'.

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Section: Discussioncontrasting

confidence: 88%

Section: Discussionsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

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Biomechanical Stresses in Computer-Aided Design and in Data Entry

Cail

Aptel

2003

International Journal of Occupational Safety and Ergonomics

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“…At the same time, definitions of keyboard kinematics have documented that there were few significant differences between the right and left hand [28]. Simoneau et al [29], have recorded 62° and 66° of mean pronation for the left and right forearms, respectively, in 90 professional touch typists during typing. One possible explanation of our finding is the long term computer mouse use by the dominant hand.…”

Section: Study Of Nerve Conduction In Computer Users O R I G I N a L mentioning

confidence: 99%

Influence of the long term use of a computer on median, ulnar and radial sensory nerves in the wrist region

Bamaç¹,

Çolak²,

Dundar³

et al. 2014

IJOMEH

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Objectives: Repetitive microtrauma or overuse injuries may often affect upper extremities of the long term computer users. The aim of this study was to compare sensory nerve conduction velocities (SNCV) for median, radial and ulnar nerves in the wrist of computer users with the same parameters in controls who do not use computers regularly. Material and Methods: Twenty one male computer users (age: mean (M) = 28.3 years ± standard deviation (SD) = 7.5 years) and 21 male control subjects (age: M±SD = 24.1±4.6 years) were recruited for the study. Limb length and the perimeters of the dominant arm and forearm were measured for each subject. The neurophysiological study consisted of measuring sensory nerve conduction of the median, ulnar and radial nerves. Results: The sensory conduction velocities of both median and ulnar nerves were significantly delayed in the dominant arm of the computer users compared to the controls. In addition, sensory conduction velocity of the median nerve was significantly delayed in the dominant extremity of the computer users compared to their non-dominant extremity. Conclusions: This study shows that computer users have a tendency toward developing median and ulnar sensory nerve damage in the wrist region. Mechanism of delayed SNCV in the median and ulnar nerves may be due to sustained extension and ulnar deviation of the wrist during computer mouse use and typing. Reduced SNCV changes were more apparent on the dominant side of the median nerve. This may indicate the increased neural deficits related to an increased use of the dominant side. Further investigation is needed to determine how to reduce potential risk factors at this stage in order to prevent development of median or ulnar neuropathy in the long term computer users.

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“…The occupational risk factors of distal upper extremity musculoskeletal disorders (MSDs), such as carpal tunnel syndrome (CTS) and wrist tenosynovitis, are thought to be due to excessive use (up to 100 000 keystrokes per day 13 ) and the deviated wrist posture noted while typing. 18,26 This paper will explore how the design components of a conventional computer keyboard could contribute to MSDs and how alternative keyboard designs could reduce, in theory, the risk of MSDs.…”

mentioning

confidence: 99%

Design Features of Alternative Computer Keyboards: A Review of Experimental Data

Marklin

Simoneau²

2004

J Orthop Sports Phys Ther

Self Cite

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Design of computer keyboards no longer is limited to the flat keyboards that are typically shipped with personal computers. Keyboards now exist that are split into halves and these halves can be slanted away from each other (creating a triangle between the halves), sloped downward toward the visual display terminal, tilted upward like a tent, or simply separated. These design features are intended to alleviate discomfort and possible musculoskeletal disorders that have been suggested to be associated with the extensive use of conventional computer keyboards. The geometry of conventional keyboards requires the wrists to be in 10°to 15°of ulnar deviation and 20°of extension and the forearms to be nearly fully pronated while typing. A review of the available experimental data collected on 10-digit touch typists indicates that (1) keyboards with a slant angle (half of the opening angle) of 10°to 12.5°or keyboards with halves separated to approximately shoulder width are both effective in placing the wrist in near neutral (0°) ulnar/radial deviation when typing, (2) wrist extension can be reduced to near neutral (0°) when a keyboard with a negative slope of 7.5°is used, contingent on the wrist rest also sloping with the keyboard, and (3) tilting the keyboard halves 20°to 30°is effective in reducing forearm pronation to approximately 45°. These studies also indicate that experienced 10-digit touch typists readily adapt (within 10 minutes) to these individual alternative keyboard features, and can type with approximately the same speed and accuracy as with the conventional keyboard. While placing the wrist and forearm in a more neutral position could, in theory, reduce the incidence of musculoskeletal disorders, randomized controlled trials are necessary before strong recommendations can be made on the effectiveness of alternative keyboards for the prevention and/or treatment of musculoskeletal disorders. In the absence of these randomized controlled trials, the information in this article provides preliminary guidance to clinicians in their evaluation of computer keyboards and workstations and their recommendations to patients.

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Wrist and Forearm Postures of Users of Conventional Computer Keyboards

Cited by 42 publications

References 16 publications

Biomechanical Stresses in Computer-Aided Design and in Data Entry

Biomechanical Stresses in Computer-Aided Design and in Data Entry

Influence of the long term use of a computer on median, ulnar and radial sensory nerves in the wrist region

Design Features of Alternative Computer Keyboards: A Review of Experimental Data

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