The Effect of Split and Vertically-Inclined Computer Keyboards on Wrist and Forearm Posture

1997 ◽  
Vol 41 (1) ◽  
pp. 642-646 ◽  
Author(s):  
Richard W. Marklin ◽  
Guy G. Simoneau ◽  
John F. Monroe
Keyword(s):  
Risk Factor ◽  
Neutral Position ◽  
Ulnar Deviation ◽  
Occupational Risk Factor ◽  
Work Related ◽  
Work Related Musculoskeletal Disorders ◽  
Tunnel Syndrome ◽  
Computer Keyboard ◽  
The Right ◽  
Neutral Posture

The significant findings from this study of 90 clerical subjects, whose forearm and wrist posture were measured while they typed on three alternative QWERTY computer keyboard designs, are the following: 1) when setup correctly, commercially-available split QWERTY keyboards reduced mean ulnar deviation of the right and left wrists from approximately 12 deg. to within 5 deg. of a neutral position compared to a conventional QWERTY keyboard. 2) with at least a 30 deg. tilt of the keyboard halves, a commercially-available vertically-inclined QWERTY keyboard reduced mean pronation of the forearm by approximately 20 deg. compared to a conventional QWERTY computer keyboard (60 to 40 deg.) The finding that split keyboards place the wrist closer to a neutral posture in the radial/ulnar plane substantially reduces one occupational risk factor of work-related musculoskeletal disorders (WMSDs), namely ulnar deviation of the wrist. The finding that vertically-inclined keyboards reduce forearm pronation substantially is advantageous, at least theoretically, to the keyboard user. However, since the origins of WMSDs, which include carpal tunnel syndrome (CTS) and tenosynovitis, tend to be multifactorial, the extent to which split keyboards or vertically-inclined keyboards could reduce the frequency or severity of WMSDs is unknown.

scholarly journals Effect of Setup Configurations of Split Computer Keyboards on Wrist Angle

2001 ◽  
Vol 81 (4) ◽  
pp. 1038-1048 ◽  
Author(s):  
Richard W Marklin ◽  
Guy G Simoneau
Keyword(s):  
Physical Therapists ◽  
Separation Distance ◽  
Opening Angle ◽  
Upper Limbs ◽  
Ulnar Deviation ◽  
Work Related ◽  
Work Related Musculoskeletal Disorders ◽  
Tunnel Syndrome ◽  
Computer Keyboard ◽  
Set Up

Abstract Background and Purpose. Alternative computer keyboards whose halves can be slanted toward each other can reduce a risk factor (ulnar deviation) for work-related musculoskeletal disorders (WMSDs) affecting the upper limbs. Two questions that computer keyboard operators face when using keyboards that can be separated into halves (split keyboards) are: (1) At what angle should the keyboard halves be opened? and (2) At what distance apart should the keyboard halves be placed? The objective of this study was to investigate the effects of the opening angle and separation distance between halves of a split keyboard on wrist ulnar deviation and typing efficiency. Methods. Eleven experienced computer keyboard operators participated in this study and used a split keyboard that was set up in a conventional (nonsplit) format and also in 3 alternative configurations: (1) centers of keyboard halves were separated at 20-cm distance, (2) keyboard halves were separated half of the distance of shoulder width, and (3) keyboard halves were separated at shoulder width distance. Results. The 3 alternative configurations resulted in ulnar deviation of both wrists that were less than ulnar deviation from typing on a conventional setup. There were no differences in ulnar deviations among the 3 alternative configurations. Discussion and Conclusion. The results of this research provide physical therapists and ergonomists with a set of configurations of a split keyboard that they can recommend to their patients or clients. All of the alternative configurations of the split keyboard are beneficial in promoting a neutral wrist position, which theoretically would decrease exposure to WMSDs such as tenosynovitis in the wrist and carpal tunnel syndrome.

Effects of Computer Keyboard Setup Parameters and User's Anthropometric Characteristics on Wrist Deviation and Typing Efficiency

1998 ◽  
Vol 42 (12) ◽  
pp. 876-880 ◽  
Author(s):  
Richard W. Marklin ◽  
Guy G. Simoneau ◽  
David Hoffman
Keyword(s):  
Separation Distance ◽  
Opening Angle ◽  
Ulnar Deviation ◽  
Left Wrist ◽  
Anthropometric Characteristics ◽  
The Mean ◽  
Computer Keyboard ◽  
The Right ◽  
Neutral Posture ◽  
Speed And Accuracy

Two questions that computer keyboard operators face when using keyboards that can be separated into halves (split keyboards) are at what angle should the keyboard halves be opened and at what distance should the keyboard halves be placed apart. The objective of this study was to investigate the effects of the opening angle and separation distance between halves of a split keyboard on wrist radial/ulnar deviation and typing efficiency. Eleven experienced typists participated in this study and typed on a split keyboard configured in the following four arrangements. 1. The keyboard halves were setup the same way as a conventional keyboard. 2. The keyboard halves were contiguous but angled, based on the user's anthropometry, to maintain a theoretical neutral posture of the user's wrists in the radial/ulnar plane. 3. The keyboard halves were separated at a fixed distance of 20 cm, and the halves were angled to maintain a theoretical neutral posture of the user's wrists in the radial/ulnar plane. 4. The keyboard halves were separated at a distance equal to the user's shoulder width, and the halves were parallel to each other, resulting in a theoretical neutral posture of the user's wrists in the radial/ulnar plane. The findings from testing these four keyboard configurations are the following: 1. The mean ulnar deviations from the alternative configurations of the split keyboard (configurations 2, 3, and 4 above) ranged from 7.0 to 8.4 for the left wrist and 2.7 to 5 deg. for the right wrist. There were no significant differences in ulnar deviations among the three alternative configurations. 2. The three alternative configurations resulted in ulnar deviation of both wrists that were significantly less than ulnar deviation from typing on the conventional setup (configuration 1 above). The mean ulnar deviations from the conventional setup were 18.9 deg. for the left wrist and 14.2 deg. for the right wrist. 3. There were no significant differences in typing speed and accuracy between the alternative and conventional configurations.

scholarly journals Musculoskeletal Disorders Symptoms among Taiwanese Bakery Workers

2020 ◽  
Vol 17 (8) ◽  
pp. 2960
Author(s):  
Yi-Lang Chen ◽  
Yan-Ting Zhong ◽  
Bang-Nan Liou ◽  
Chih-Chuan Yang
Keyword(s):  
Musculoskeletal Disorders ◽  
The Body ◽  
Self Report ◽  
Musculoskeletal Discomfort ◽  
Ulnar Deviation ◽  
Left Wrist ◽  
Work Related ◽  
Work Related Musculoskeletal Disorders ◽  
Shoulder Disorders ◽  
The Right

In this study, the Nordic Musculoskeletal Questionnaire (NMQ) was administered to a valid sample of 81 Taiwanese bakery workers to explore their discomfort or symptoms of work-related musculoskeletal disorders and identify the risk factors. Wrist postures were also examined during 3 typical dough operations (kneading, rolling, and rounding) by using an electrogoniometer. The prevalence of musculoskeletal discomfort in any part of the body in the past year among the respondents was 93.0%, with the highest prevalence of 66.3% and 51.8% in the hands/wrists (right and left), followed by the prevalence of 50.6% and 45.8% in the shoulders (right and left) and the lower back (48.2%), respectively. The results also revealed that during the 3 dough processing operations, the workers’ wrist movements in specific operations were close to the recommended limits suggested in previous studies, especially the ulnar deviation and palm flexion of the right wrist during dough kneading and the radial deviation of the left wrist during dough rolling and rounding. The study findings can be used to explain why the bakers self-report a high proportion of wrist and shoulder disorders and can also serve as a reference for task rearrangement and redesign.

An Ergonomic Computer Mouse for Professional Designers

2013 ◽  
Vol 440 ◽  
pp. 194-198
Author(s):  
Ali Faraji ◽  
Morteza Rohani Farahmand
Keyword(s):  
Interaction Design ◽  
Neutral Position ◽  
User Centered Design ◽  
Ulnar Deviation ◽  
Work Related ◽  
Library Research ◽  
Computer Mouse ◽  
Work Related Musculoskeletal Disorders ◽  
Final Design ◽  
Research Studies

Some criteria for designing an ergonomic mouse for professional computer users via scenario-based design are presented in order to decrease Work-Related Musculoskeletal Disorders (WMSDs) especially in upper limbs. Library research studies performed based on 5W-H approach extremely tend to medical, ergonomics and functional affairs. Since this study was user-centered design (interaction design), practical research studies performed for better comprehension of users needs by making use of questionnaire, interview and observation procedures in three field of design: ergonomics, functional and aesthetics. First, target group divided into three categories by using AHP method: A-users who work professionally with design, graphic and animation softwares; B-users who work professionally or unprofessionally with other softwares; and C-users who work professionally with engineering softwares. Then, 56 questionnaires are presented to this group and also they interviewed and 15 ones observed during interaction with computer mouse. Finally, 23 design criteria achieved and final idea designed based on these criteria. The most important notes that considered in final design are neutral position of wrist, ulnar deviation prevention and preventing from static and powerful grips.

The Effect of Angled Hammers on Wrist Motion

1988 ◽  
Vol 32 (11) ◽  
pp. 651-655 ◽  
Author(s):  
Richard W. Schoenmarklin
Keyword(s):  
Risk Factor ◽  
Carpal Tunnel Syndrome ◽  
Carpal Tunnel ◽  
Neutral Position ◽  
Angular Deviation ◽  
Ulnar Deviation ◽  
Wrist Motion ◽  
Radial Deviation ◽  
Tunnel Syndrome ◽  
Motion Characteristics

This research investigated the range of wrist motion characteristics associated with the ergonomic principle of “bending the tool and not the wrist” as applied to the hammer. It is thought that bending the tool reduces wrist motion, which has been shown in the literature to be a risk factor in hand/wrist disorders, such as carpal tunnel syndrome, tenosynovitis, etc. Bent hammer handles resulted in a tradeoff in beginning and ending positions of the wrist throughout a hammering stroke. Bending the hammer handle to 20 or 40 deg. resulted in significantly less ulnar deviation than a straight hammer, but also increased radial deviation. Overall, the angular deviation from neutral position in the radial/ulnar plane was significantly less for the 20 and 40 deg. hammers than for the straight hammer. This research suggests that angled hammer handles in the range of 20 to 40 degrees could possibly decrease the incidence of hand/wrist disorders caused by the use of hammers.

scholarly journals REPETITION AS A RISK FACTOR FOR THE DEVELOPMENT OF MUSCULOSKELETAL DISORDERS

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Sonja Pavlovic-Veselinovic
Keyword(s):  
Risk Factors ◽  
Risk Assessment ◽  
Risk Factor ◽  
Key Words ◽  
Musculoskeletal Disorders ◽  
World Economy ◽  
Repetitive Work ◽  
Work Related ◽  
Work Related Musculoskeletal Disorders ◽  
Repetitive Strain

Work-related musculoskeletal disorders (WRMSDs) are becoming a major problem in world economy. There is many and various risk factors that contribute to their development. Repetitive work is one of the most important risk factor. In this paper is described the body's response to repetitive strain, existing methods for evaluation/ quantification of repetition as risk factor for musculoskeletal disorders. The author proposes a new multidimensional scale for rating the level of risk of repetitive work, which may be useful in the risk assessment of the workplace. Key words: ergonomics, work related musculoskeletal disorders, risk assessment.

scholarly journals Quantitative Measures of Physical Risk Factors Associated with Work-Related Musculoskeletal Disorders of the Elbow: A Systematic Review

2019 ◽  
Vol 16 (1) ◽  
pp. 130 ◽  
Author(s):  
David H. Seidel ◽  
Dirk M. Ditchen ◽  
Ulrike M. Hoehne-Hückstädt ◽  
Monika A. Rieger ◽  
Benjamin Steinhilber
Keyword(s):  
Risk Factors ◽  
Risk Factor ◽  
Musculoskeletal Disorders ◽  
Well Being ◽  
Special Focus ◽  
Factors Associated ◽  
Work Related ◽  
Work Related Musculoskeletal Disorders ◽  
Physical Risk ◽  
Physical Risk Factors

Background: Work-related musculoskeletal disorders at the elbow are a common health problem, which highly impacts workers’ well-being and performance. Besides existing qualitative information, there is a clear lack of quantitative information of physical risk factors associated with specific disorders at the elbow (SDEs). Objective: To provide evidence-based quantitative measures of physical risk factors associated with SDEs. Methods: Studies were searched from 2007 to 2017 in Medline, EMBASE, and Cochrane Work. The identified risk factors were grouped in main- and sub-categories of exposure using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework for rating evidence. Results: 133 different risk-factor specifications were identified in 10/524 articles and were grouped into 5 main- and 16 sub-categories of exposure. The risk factors were significantly associated with lateral epicondylitis, medial epicondylitis, or ulnar neuropathy. Significant risk factors such as wrist angular velocity (5°/s, with increasing prevalence ratio of 0.10%/(°/s), or forearm supination (≥45° and ≥5% of time combined with forceful lifting) were found. Conclusions: This review delivers a categorization of work-related physical risk-factor specifications for SDEs with a special focus on quantitative measures, ranked for evidence. These results may build the base for developing risk assessment methods and prospective preventive measures.

Effects of Handle Angle and Work Orientation on Hammering: I. Wrist Motion and Hammering Performance

1989 ◽  
Vol 31 (4) ◽  
pp. 397-411 ◽  
Author(s):  
Richard W. Schoenmarklin ◽  
William S. Marras
Keyword(s):  
Risk Factor ◽  
Ulnar Deviation ◽  
Trade Off ◽  
Wrist Motion ◽  
Starting Position ◽  
Impact Position ◽  
Novice Users ◽  
Tunnel Syndrome ◽  
Motion Characteristics ◽  
The Impact

This research investigated the range of wrist motion characteristics associated with the ergonomic principle of “bending the tool and not the wrist” as applied to the hammer. It is thought that bending the tool reduces angular wrist motion, which has been shown in the literature to be a risk factor in hand/wrist disorders such as carpal tunnel syndrome and tenosynovitis. Hammer handles angled at 0 (straight), 20, and 40 deg were investigated in this study. For novices, hammer handles bent at 20 and 40 deg resulted in less total ulnar deviation than straight hammers. However, there was a trade-off in beginning and ending positions of the wrist in that the angled hammers reduced ulnar deviation at the impact position but increased radial deviation at the starting position of a hammer stroke. Handle angle did not significantly affect hammering performance. Wrist motion was affected minimally by hammering orientation, but hammering performance was significantly worse in the wall orientation compared with the bench orientation. This research suggests that for novice users, hammers with handles bent in the range of 20 to 40 deg could possibly decrease the incidence of hand/wrist disorders caused by hammering.

scholarly journals Caracterização do perfil de adoecimento por LER/DORT em um centro de referência em saúde do trabalhador / Characterization of the profile of adoption by reading / wrath in a worker health reference center

2020 ◽  
Vol 4 (4) ◽  
pp. 631-645
Author(s):  
Nilson Rogério da Silva ◽  
Pedro Fernandes Junqui ◽  
Meire Luci da Silva
Keyword(s):  
Occupational Health ◽  
Musculoskeletal Disorders ◽  
Sao Paulo ◽  
São Paulo ◽  
Reference Center ◽  
Work Related ◽  
Work Related Musculoskeletal Disorders ◽  
Tunnel Syndrome ◽  
Repetitive Strain ◽  
Professional Information

As Lesões por Esforço Repetitivo/Distúrbios Osteomusculares Relacionados ao Trabalho apareceram com maior incidência a partir do final dos anos 70, com destaque na década de 80. Atualmente um problema significativo entre trabalhadores nos mais diversos segmentos laborais, ocasionando elevado contingente de trabalhadores lesionados com prejuízo para saúde e consequentemente para produção, justificando a importância de estudos dessa temática. O objetivo deste estudo foi caracterizar o perfil de adoecimento por LER/DORT de usuários do Centro de Referência em Saúde do Trabalhador de uma cidade de médio porte no interior de São Paulo, entre o período de 2016 a 2017. A coleta de dados foi realizada a partir de um banco de dados informatizado, onde são registradas informações pessoais e profissionais dos usuários, bem como registro de acompanhamento e evolução do tratamento. Para a análise dos resultados foram aplicados cálculos de estatística descritiva. Os resultados revelaram prevalência da Síndrome do Manguito Rotador, seguida da Dor Lombar Baixa e Síndrome do Túnel do Carpo. Estas foram mais frequentes em mulheres, trabalhadoras domésticas, com predomínio de adoecimento acima de 40 anos de idade e em relação à evolução clínica houve predomínio de alta por melhora e elevada evasão do tratamento. Espera-se que os resultados ofereçam subsídios para a implantação de ações de prevenção e promoção da saúde, bem como de intervenção junto aos trabalhadores, além de nortear políticas públicas de atenção a essa população. AbstractRepetitive Strain Injury / Work-Related Musculoskeletal Disorders appeared with greater incidence from the late 1970s onwards, especially in the 1980s. Currently a significant problem among workers in the most diverse occupational segments, causing a high contingent of injured workers with injury for health and consequently for production, justifying the importance of studies of this theme. The aim of this study was to characterize the Repetitive Strain Injury / Work-Related Musculoskeletal Disorders profile of users of the Occupational Health Reference Center of a medium-sized city in the interior of São Paulo, from 2016 to 2017. Data collection was performed from a computerized database, where users' personal and professional information is recorded, as well as monitoring and treatment evolution records. For the analysis of the results, descriptive statistics calculations were applied. The results revealed a prevalence of rotator cuff syndrome, followed by low back pain and carpal tunnel syndrome. These were more frequent in women, domestic workers, with a predominance of illness above 40 years of age and in relation to clinical evolution, there was a predominance of high for improvement and high treatment dropout. The results are expected to offer subsidies for the implementation of health prevention and promotion actions, as well as intervention with the workers, besides guiding public policies of attention to this population.Keywords: Occupational Diseases, Occupational Health, Occupational Therapy, Rehabilitation, Vocational ResumenLas lesiones por esfuerzo repetitivo / trastornos musculoesqueléticos relacionados con el trabajo aparecieron con mayor incidencia desde finales de los años setenta en adelante, especialmente en la década de 1980. Actualmente es un problema importante entre los trabajadores en los segmentos laborales más diversos, causando un alto contingente de trabajadores lesionados con lesiones. para la salud y, en consecuencia, para la producción, justificando la importancia de los estudios sobre este tema. El objetivo de este estudio fue caracterizar el perfil de enfermedad lesiones por esfuerzo repetitivo / trastornos musculoesqueléticos relacionados con el trabajo de los usuarios del Centro de Referencia de Salud Ocupacional de una ciudad mediana en el interior de São Paulo, de 2016 a 2017. Se realizó la recolección de datos. de una base de datos computarizada, donde se registra la información personal y profesional de los usuarios, así como los registros de seguimiento y evolución del tratamiento. Para el análisis de los resultados, se aplicaron cálculos estadísticos descriptivos. Los resultados revelaron una prevalencia del síndrome del manguito rotador, seguido de dolor lumbar y síndrome del túnel carpiano. Estos fueron más frecuentes en mujeres, trabajadoras domésticas, con un predominio de enfermedades mayores de 40 años y en relación con la evolución clínica, hubo un predominio de alta para mejoría y alta deserción del tratamiento. Se espera que los resultados ofrezcan subsidios para la implementación de acciones de prevención y promoción de la salud, así como la intervención con los trabajadores, además de orientar políticas públicas de atención a esta población.Palabrasclave: Enfermedades Profesionales, Salud Laboral, Terapia Ocupacional, Rehabilitación Vocacional.  

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