The influence of desk and display design on posture and muscle activity variability whilst performing information technology tasks (original) (raw)
Related papers
Journal of Electromyography and Kinesiology, 2008
Computer display height and desk design to allow forearm support are two critical design features of workstations for information technology tasks. However there is currently no 3D description of head and neck posture with different computer display heights and no direct comparison to paper based information technology tasks. There is also inconsistent evidence on the effect of forearm support on posture and no evidence on whether these features interact. This study compared the 3D head, neck and upper limb postures of 18 male and 18 female young adults whilst working with different display and desk design conditions. There was no substantial interaction between display height and desk design. Lower display heights increased head and neck flexion with more spinal asymmetry when working with paper. The curved desk, designed to provide forearm support, increased scapula elevation/protraction and shoulder flexion/ abduction.
Numerous office employees who work with computer workstations endure various musculoskeletal discomforts every day. This study intends to reduce musculoskeletal discomfort caused by desktop computer workstations, which causes productivity losses and several medical costs. A survey was distributed to 42 participants who use desktop computer workstations for at least 6 hours per day. Specific anthropometric measurements were collected to design an optimized computer workstation. Ten respondents were randomly selected to participate in an electromyogram (EMG) experiment to determine muscular impulse differences between standard and optimized desktop computer workstations. The EMG results indicated that discomforts are pronounced in shoulder, neck, lower and upper back and hand-wrist regions. The risk assessment model showed that experiencing troubles in the neck (p=0.022), shoulder (p=0.023), and wrist/hands (p=0.020) within 12 months were the significant factors. ANOVA results proved that the optimized design of a computer workstation causes less muscular pressure on the muscles at each measured body region.
Applied Ergonomics, 2019
Sit-stand tables are introduced in offices to increase variation in gross body posture, but the extent to which upper body posture variation is also affected has not previously been addressed. Neck, trunk, and upper arm postures (means and minute-to-minute variances) were determined during periods of sitting and standing from 24 office workers using sit-stand tables to perform computer work. Posture variability resulting from different temporal compositions of sitting and standing computer work was then predicted for the neck, trunk and upper arm by simulations. Postural variability during computer work could be increased up to threefold when 20-60% of the work was performed standing (i.e. 40-80% performed sitting), compared to performing computer work only sitting. The exact composition of sit-stand proportions leading to maximum variability, as well as the potential size of the increase in variability, differed considerably between workers. Guidelines for sit-stand table use should note these large inter-individual differences.
Effects of portable computing devices on posture, muscle activation levels and efficiency
Applied ergonomics, 2014
Very little research exists on ergonomic exposures when using portable computing devices. This study quantified muscle activity (forearm and neck), posture (wrist, forearm and neck), and performance (gross typing speed and error rates) differences across three portable computing devices (laptop, netbook, and slate computer) and two work settings (desk and computer) during data entry tasks. Twelve participants completed test sessions on a single computer using a test-rest-test protocol (30min of work at one work setting, 15min of rest, 30min of work at the other work setting). The slate computer resulted in significantly more non-neutral wrist, elbow and neck postures, particularly when working on the sofa. Performance on the slate computer was four times less than that of the other computers, though lower muscle activity levels were also found. Potential or injury or illness may be elevated when working on smaller, portable computers in non-traditional work settings.
Ergonomic risk factors associated with musculokeletal disorders in computer workstation
2017
Ergonomics Risk Factors (ERFs) at computer works are commonly related to Musculoskeletal Disorders (MSDs) such as repetitive movements, doing work in awkward postures and static postures while prolonged seating at works. The main objective of this study was to investigate the ergonomic risk factors associated with MSDs among employees in computer workstation. In this study, the data were obtained by structured interview using self-reported questionnaire and direct observation. The results show that there is significant association between neck and stress score with musculoskeletal symptoms and among office workers. As a conclusion, by assessing ERFs at workplace, the effectiveness of workplace interventions can be evaluated without waiting for changes in the prevalence of MSDs.
Characterization of posture and comfort in laptop users in non-desk settings
Applied Ergonomics, 2012
Laptop computers may be used in a variety of postures not coupled to the office workstation. Using passive motion analysis, this study examined mean joint angles during a short typing/editing task in college students (n ¼ 20), in up to seven positions. Comfort was assessed after task execution through a body map. For three required postures, joint angles in a prone posture were different than those while seated at a couch with feet either on floor or on ottoman. Specifically, the prone posture was characterized by comparatively non-neutral shoulders, elbows and wrists, and pronounced neck extension. Significantly greater intensity and more regions of discomfort were marked for the prone posture than for the seated postures. It is recommended that the prone posture only be assumed briefly during laptop use. Exposure to laptops outside of the office setting should be assessed in future epidemiologic studies of musculoskeletal complaints and computer use.
Ergonomic Risk Factors associated with Muscuslokeletal Disorders in Computer Workstation
Ergonomics Risk Factors (ERFs) at computer works are commonly related to Musculoskeletal Disorders (MSDs) such as repetitive movements, doing work in awkward postures and static postures while prolonged seating at works. The main objective of this study was to investigate the ergonomic risk factors associated with MSDs among employees in computer workstation. In this study, the data were obtained by structured interview using self-reported questionnaire and direct observation. The results show that there is significant association between neck and stress score with musculoskeletal symptoms and among office workers. As a conclusion, by assessing ERFs at workplace, the effectiveness of workplace interventions can be evaluated without waiting for changes in the prevalence of MSDs.
Effect of Notebook Computer Display Tilt Angle on Muscle Activity among Notebook User
The highly compact and easy to be carry has made notebook as part of daily use by many students, teenagers and young executives. However, when each of the notebook manual for laptop operation was reviewed, we are not able to find a complete guideline of the tilt angle of the computer screen for the user. Therefore without a proper recommendation on the LCD display angle, there is high possibility that the user will tend to perform constrained postures and higher neck-shoulder muscle activity when using notebook. The objective of this study is to investigate the effects of the LCD tilt angle of notebook computers on neck-shoulder muscle activity and to recommend the tilt angle suitable for notebook users. An experimental study was done among 60 university notebook computer users. Respondents were required to perform a repetitive typing task for over 20 minutes at four different adjustments to the LCD tilt angle. The neck-shoulder muscle activity and individual discomfort rating (VAS) were measured by electromyography, and goniometer respectively. At a tilt angle of 100°, there is an increased normalized muscle activity on Sternocleidomastoid muscle and % change in muscle per measurement period. However, muscle activity and discomfort ratings were lowest at a tilt angle of 110°. The findings show that non-ergonomic features of notebook computers induced a constrained posture at the neck-shoulder muscle region. At a tilt angle of 110°, muscles used the lowest normalized muscle activity. As conclusion, tilt angle at 110 is suggested as the best tilt angle. The points of interest raised in this paper were the combination of LCD tilt angle adjustment and the suggestion of ergonomics postures when contemplating the use of notebook computers.
2012
The present study, a part of the PROOF (PRedicting Occupational biomechanics in OFfice workers) study, aimed to determine whether trapezius muscle effort was different across computer activities in a field study of computer workers, and also investigated whether head and shoulder postures were different across computer activities. One hundred twenty participants were measured continuously for two hours each while performing their own computer work. Keyboard activities were associated with the highest intensity of left and right trapezius muscle efforts, and mouse activities were associated with the smallest variability in left and right trapezius muscle efforts. Corresponding trends in head and shoulder postures included that the greatest head flexion and left and right shoulder internal rotation was observed during keyboard activities, and that the smallest variability in head flexion, head lateral tilt, and right shoulder internal rotation was observed during mouse activities. Identifying which muscle efforts and postures are different across computer activities is the first essential step for developing prediction rules for muscle efforts and postures, which can be used to link muscle efforts and postures to musculoskeletal symptoms in epidemiological studies.