Work - Volume 52, issue 2

Article Type: Editorial

DOI: 10.3233/WOR-152169

Citation: Work, vol. 52, no. 2, pp. 215-216, 2015

Authors: Bruno Garza, J.L. | Young, J.G.

Article Type: Research Article

Abstract: BACKGROUND: Extended use of conventional computer input devices is associated with negative musculoskeletal outcomes. While many alternative designs have been proposed, it is unclear whether these devices reduce biomechanical loading and musculoskeletal outcomes. OBJECTIVE: To review studies describing and evaluating the biomechanical loading and musculoskeletal outcomes associated with conventional and alternative input devices. METHODS: Included studies evaluated biomechanical loading and/or musculoskeletal outcomes of users’ distal or proximal upper extremity regions associated with the operation of alternative input devices (pointing devices, mice, other devices) that could be used in a desktop personal computing environment during typical office …work. RESULTS: Some alternative pointing device designs (e.g. rollerbar) were consistently associated with decreased biomechanical loading while other designs had inconsistent results across studies. Most alternative keyboards evaluated in the literature reduce biomechanical loading and musculoskeletal outcomes. Studies of other input devices (e.g. touchscreen and gestural controls) were rare, however, those reported to date indicate that these devices are currently unsuitable as replacements for traditional devices. CONCLUSIONS: Alternative input devices that reduce biomechanical loading may make better choices for preventing or alleviating musculoskeletal outcomes during computer use, however, it is unclear whether many existing designs are effective. Show more

Keywords: Human computer interaction, ergonomics, intervention, occupational

DOI: 10.3233/WOR-152161

Citation: Work, vol. 52, no. 2, pp. 217-230, 2015

Authors: Kim, Jeong Ho | Aulck, Lovenoor | Trippany, David | Johnson, Peter W.

Article Type: Research Article

Abstract: BACKGROUND: Contact pressure is a risk factor which can contribute to musculoskeletal disorders. OBJECTIVE: The objective of the present study was to determine whether a work surface with a soft, pliable front edge could reduce contact pressure, muscle activity, and subjective musculoskeletal comfort, and improve wrist posture relative to a conventional, hard work surface. METHODS: In a repeated-measures blinded experiment with eighteen subjects (8 females and 10 males), contact pressure, wrist posture, typing productivity, perceived fatigue, wrist and shoulder muscle activity, and subjective comfort were compared between the two different work surfaces during keyboard use, mouse …use and mixed mouse and keyboard use. RESULTS: The results showed that across the three modes of computer work, the contact pressure was lower on the soft-edge work surface compared to the conventional work surface (p ’s <0.03) and subjects reported to have less perceived fatigue in the forearms and wrists. No differences in muscle activity, wrist posture, and subjective comfort were measured between the two work surfaces. CONCLUSIONS: Given the significant reduction in contact pressure and corresponding lower ratings in perceived fatigue, the soft-edge work surface subjectively and objectively improved measures of contact stress which may reduce physical exposures associated with the onset and development of musculoskeletal disorders. Show more

Keywords: Electromyography, electrogoniometer, contact pressure, office ergonomics

DOI: 10.3233/WOR-152166

Citation: Work, vol. 52, no. 2, pp. 231-244, 2015

Authors: Odell, Dan | Johnson, Peter

Article Type: Research Article

Abstract: BACKGROUND: Modern computer users use the mouse almost three times as much as the keyboard. As exposure rates are high, improving upper extremity posture while using a computer mouse is desirable due to the fact that posture is one risk factor for injury. Previous studies have found posture benefits associated with using alternative mouse designs, but at the cost of performance and preference. OBJECTIVE: To develop new computer mouse shapes, evaluate them versus benchmarks, and determine whether there are differences in wrist posture, pointing performance, and subjective measures. METHODS: Three concept mice were designed and evaluated …relative to two existing benchmark models: a traditional flat mouse, and an alternative upright mouse. Using a repeated measures design, twelve subjects performed a standardized point-and-click task with each mouse. Pointing performance and wrist posture was measured, along with perceived fatigue ratings and subjective preferences pre and post use. RESULTS: All of the concept mice were shown to reduce forearm pronation relative to the traditional flat mouse. There were no differences in pointing performance between the traditional flat mouse and the concept mice. In contrast, the fully vertical mouse reduced pronation but had the poorest pointing performance. Perceived fatigue and subjective preferences were consistently better for one concept mouse. CONCLUSIONS: Increasing mouse height and angling the mouse topcase can improve wrist posture without negatively affecting performance. Show more

Keywords: Human-computer interaction, design, ergonomics

DOI: 10.3233/WOR-152167

Citation: Work, vol. 52, no. 2, pp. 245-253, 2015

Authors: Karol, Sohit | Robertson, Michelle M.

Article Type: Review Article

Abstract: BACKGROUND: Sedentary work is associated with many adverse health outcomes, and sit-stand workstations in offices have emerged as a way to counteract sedentary work. OBJECTIVE: This paper reviews the existing knowledge on sit-stand workstations, treadmill workstations and bicycle workstations. METHODS: The inclusion/exclusion criteria were: 1) empirical research examining the effectiveness of sit-stand workstations in lab or field studies, 2) working adult population, 3) sit-stand workstation interventions where workers performed the same task from a seated or standing position, 4) outcomes measures of discomfort (comfort), performance, sit-stand behaviors, user satisfaction, kinematic and physiological measures. Search terms were: …sit-stand, treadmill, bicycle, workstations, sedentary behavior, office ergonomics, and comfort. RESULTS: Many studies considered productivity, comfort and physiological measures as important outcomes to assess the efficacy of sit-stand workstations and the experimental design was variable. Preliminary data suggests that some amount of standing during an 8-hour workday could be beneficial without compromising user comfort or productivity; however, there is very little data on the efficacy of treadmill and bicycle workstations. CONCLUSIONS: Based on these preliminary data from 26 studies, conducting large scale randomized controlled trials with ergonomic training as their essential component is recommended to understand the benefits of sit-stand workstations for prevention of sedentary work. Show more

Keywords: Musculoskeletal symptoms, ergonomics training, productivity, comfort and health

DOI: 10.3233/WOR-152168

Citation: Work, vol. 52, no. 2, pp. 255-267, 2015

Authors: Dennerlein, Jack T.

Article Type: Review Article

Abstract: BACKGROUND: Because mobile computing technologies, such as notebook computers, smart mobile phones, and tablet computers afford users many different configurations through their intended mobility, there is concern about their effects on musculoskeletal pain and a need for usage recommendations. OBJECTIVE: Therefore the main goal of this paper to determine which best practices surrounding the use of mobile computing devices can be gleaned from current field and laboratory studies of mobile computing devices. METHODS: An expert review was completed. RESULTS: Field studies have documented various user configurations, which often include non-neutral postures, that users adopt …when using mobile technology, along with some evidence suggesting that longer duration of use is associated with more discomfort. It is therefore prudent for users to take advantage of their mobility and not get stuck in any given posture for too long. The use of accessories such as appropriate cases or riser stands, as well as external keyboards and pointing devices, can also improve postures and comfort. CONCLUSIONS: Overall, the state of ergonomics for mobile technology is a work in progress and there are more research questions to be addressed. Show more

Keywords: Posture, wrist posture, injury, occupation, mobile phones, texting

DOI: 10.3233/WOR-152159

Citation: Work, vol. 52, no. 2, pp. 269-277, 2015

Authors: Kamp, I. | Van Veen, S.A.T. | Vink, P.

Article Type: Review Article

Abstract: BACKGROUND: The use of mobile devices as an addition to or replacement of desktop computers for traditional office work results in more flexibility of workplaces. Consequently transportation time is used for office work and this asks for comfortable mobile offices. OBJECTIVE: The aim of this review is providing a framework of the relevant elements for comfortable mobile offices and defining needs for future research. METHODS: This literature review draws on 68 papers, theses, reviews and critiques. RESULTS: The framework is based on existing literature on traditional office ergonomics and comfort literature for different transportation …modes like trains, buses, airplanes and cars. CONCLUSIONS: The main differences with traditional offices are the type of devices, dynamic versus static situation, the sole use of mobile devices and therefore the need for a good arm support to avoid an uncomfortable neck flexion, limited space, and the presence of strangers which influence the privacy perception. Important topics for future research are: the effect on the employee and the environment of the ability and demand of working anywhere, and the requirements for the physical aspects of mobile offices. Show more

Keywords: Comfort, transportation interior, mobile devices, office ergonomics

DOI: 10.3233/WOR-152165

Citation: Work, vol. 52, no. 2, pp. 279-287, 2015

Authors: Honan, Meg

Article Type: Review Article

Abstract: BACKGROUND: Places of work have been completely transformed by innovations in mobile work tools and ever-present access to internet data. OBJECTIVE: This article characterizes use patterns and provides preliminary considerations for productive and comfortable use of common mobile devices. METHOD: Two surveys described trends in mobile work. In the first, ergonomics professionals who oversee programs reported common mobile devices, their users and what data is accessed. The second, an end user survey, explored common activities performed on mobile devices, duration of use and locations where mobile work is common. RESULTS: The survey results provide …a baseline data point for the status of mobile work in early 2014. DISCUSSION: Research indicates that additional risks have been introduced to the neck, thumbs and hands when using mobile devices. Possible trends regarding device use and work locations emerge. Intervention studies provide some direction for the practitioner. Practical strategies are outlined to reduce exposure intensity and duration. CONCLUSION: Contemporary mobile work presents tremendous change and opportunity for ergonomists and researchers to keep pace with fitting the changing models of work to the person. Continued research is needed on current mobile device use patterns to better understand ergonomic risk exposure in this rapidly changing realm. Show more

Keywords: Mobile device use, collaborative work, exposure, smartphone, tablet, laptop

DOI: 10.3233/WOR-152164

Citation: Work, vol. 52, no. 2, pp. 289-301, 2015

Authors: Gowrisankaran, Sowjanya | Sheedy, James E.

Article Type: Review Article

Abstract: BACKGROUND: Computer vision syndrome (CVS) is a collection of symptoms related to prolonged work at a computer display. OBJECTIVE: This article reviews the current knowledge about the symptoms, related factors and treatment modalities for CVS. METHODS: Relevant literature on CVS published during the past 65 years was analyzed. RESULTS: Symptoms reported by computer users are classified into internal ocular symptoms (strain and ache), external ocular symptoms (dryness, irritation, burning), visual symptoms (blur, double vision) and musculoskeletal symptoms (neck and shoulder pain). The major factors associated with CVS are either environmental (improper lighting, display position …and viewing distance) and/or dependent on the user’s visual abilities (uncorrected refractive error, oculomotor disorders and tear film abnormalities). CONCLUSION: Although the factors associated with CVS have been identified the physiological mechanisms that underlie CVS are not completely understood. Additionally, advances in technology have led to the increased use of hand-held devices, which might impose somewhat different visual challenges compared to desktop displays. Further research is required to better understand the physiological mechanisms underlying CVS and symptoms associated with the use of hand-held and stereoscopic displays. Show more

Keywords: Asthenopia, visual stress, visual-ergonomics

DOI: 10.3233/WOR-152162

Citation: Work, vol. 52, no. 2, pp. 303-314, 2015

Authors: Osterhaus, Werner | Hemphälä, Hillevi | Nylén, Per

Article Type: Review Article

Abstract: BACKGROUND: The visual conditions for computer work are complex and include several factors that need to be well controlled. These factors include the lighting system, the design of the computer and screen itself, the screens position and orientation within the room, the surface reflectances and colours of the room, and the visualability of the worker. OBJECTIVE: The objective was to review the literature (including standards) on lighting for computer work in an accessible summary. This contribution focuses on lighting for computer work, but the reader is reminded of the fact that lighting continuously interacts with the other factors …mentioned above. RESULTS/CONCLUSION: The combined visual conditions shall enable the worker to see and perform the work task without causing unnecessary strain for the eyes or the other parts of the body. The main lighting-related factors in the visual environment to evaluate are: illuminance, luminance, direction of light, glare, correlated colour temperature of the light source (CCT), colour rendering of the light source, and the non-visual effects (such as non-visual flicker). A visual ergonomics checklist is presented as a guide to analyse the visual environment. Show more

Keywords: Illuminance, luminance, computer screen, computer work

DOI: 10.3233/WOR-152163

Citation: Work, vol. 52, no. 2, pp. 315-328, 2015