Effects of a sit-stand-walk intervention on musculoskeletal discomfort, productivity, and perceived physical and mental fatigue, for computer-based work (original) (raw)
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International Journal of Environmental Research and Public Health
Office workers are exposed to high levels of sedentary time. In addition to cardio-vascular and metabolic health risks, this sedentary time may have musculoskeletal and/or cognitive impacts on office workers. Participants (n = 20) undertook two hours of laboratory-based sitting computer work to investigate changes in discomfort and cognitive function (sustained attention and problem solving), along with muscle fatigue, movement and mental state. Over time, discomfort increased in all body areas (total body IRR [95% confidence interval]: 1.43 [1.33–1.53]) reaching clinically meaningful levels in the low back and hip/thigh/buttock areas. Creative problem solving errors increased (β = 0.25 [0.03–1.47]) while sustained attention did not change. There was no change in erector spinae, trapezius, rectus femoris, biceps femoris and external oblique median frequency or amplitude; low back angle changed towards less lordosis, pelvis movement increased, and mental state deteriorated. There wer...
Occupational and …, 2005
To examine the effect of two workstation and postural interventions on the incidence of musculoskeletal symptoms among computer users. Methods: Randomised controlled trial of two distinct workstation and postural interventions (an alternate intervention and a conventional intervention) among 376 persons using computer keyboards for more than 15 hours per week. The incidence of neck/shoulder symptoms and hand/arm symptoms during six months of follow up among individuals in the intervention groups was compared to the incidence in computer users who did not receive an intervention (comparison group). For individuals in the intervention groups, study staff adjusted workstations, where possible, and trained individuals to assume the intervention postures. Individuals reported musculoskeletal symptoms in a weekly diary. Participants who reported discomfort intensity of 6 or greater on a 0-10 visual analogue scale or who reported musculoskeletal symptoms requiring use of analgesic medication were considered symptomatic. Results: There were no significant differences in the incidence of musculoskeletal symptoms among the three intervention groups. Twenty two (18.5%) participants in the alternate intervention group, 25 (20.2%) in the conventional intervention group, and 25 (21.7%) in the comparison group developed incident arm or hand symptoms. Thirty eight (33.3%) participants in the alternate intervention group, 36 (31.0%) in the conventional intervention group, and 33 (30.3%) in the comparison group developed incident neck or shoulder symptoms. Compliance with all components of the intervention was attained for only 25-38% of individuals, due mainly to the inflexibility of workstation configurations. Conclusions: This study provides evidence that two specific workplace postural interventions are unlikely to reduce the risk of upper extremity musculoskeletal symptoms among computer users. Keyboard shoulder abduction of 210˚to 20N Keyboard inner elbow angle of 80˚to 100N Keyboard wrist ulnar deviation of 210˚to 10N Keyboard wrist extension of 210˚to 10N Keyboard wrist rest present N Mouse wrist ulnar deviation of 210˚to 10N Mouse wrist extension of 210˚to 10N Armrest present N High quality chair present Policy implications N The study provides no empirical basis for recommendation of one posture versus another for prevention of musculoskeletal symptoms among computer users. Main message N No differences in risk of musculoskeletal symptoms were observed among participants randomly assigned to two workstation and postural interventions in comparison to participants who received no workstation or postural intervention. *Head tilt angle is defined as the angle formed between a line defined by the tragion of the ear and the infraorbitale of the eye and the horizon. To clarify the meaning of head tilt angle values, increasing neck extension results in larger values for head tilt angle and increasing neck flexion results in smaller (including negative) values. **Characteristics of high quality chair: easily (pneumatically) adjustable for height, adjustable height backrest, full contoured backrest, adjustable seat pan angle, round waterfall seatpan edge, five legged base. 10a
Ergonomics, musculoskeletal disorders and computer work
Occupational Medicine, 2005
This review summarizes the knowledge regarding ergonomics and musculoskeletal disorders and the association with computer work. A model of musculoskeletal disorders and computer work is proposed and the evidence and implications of the model together with issues for future research is discussed. The model emphasizes the associations between work organization, psychosocial factors and mental stress on the one hand and physical demands and physical load on the other. It is hypothesized that perceived muscular tension is an early sign of musculoskeletal disorder, which arises as a result of work organizational and psychosocial factors as well as from physical load and individual factors. It is further hypothesized that perceptions of exertion and comfort are other possible early signs of musculoskeletal disorders in computer work. Interventions aimed at reducing musculoskeletal disorders due to computer work should be directed at both physical/ergonomic factors and work organizational and psychosocial factors. Interventions should be carried out with management support and active involvement of the individual workers.
Effects of Active Workstation Use on Walking Mechanics and Work Efficiency
Recently, the amount of time dedicated to sedentary work-related tasks has increased. Further, this trend toward decreased physical activity in the workplace is expected to increase. Active workstations such as treadmill desks provide health benefits; however, concerns for the ability to walk safely and work efficiency remain unclear. The purposes of this investigation were to: 1) compare kinematics of treadmill walking (TW) with kinematics of walking while performing computer mousing tasks (WC) using a treadmill desk, and 2) examine work efficiency in terms of the time to complete computer mousing tasks during WC compared to standing (SC). Trunk and lower-extremity kinematic data were obtained from 9 males (23.4 ± 4.2 yrs; 81.7 ± 16.4 kg; 176.3 ± 5.5 cm) and 7 females (23.0 ± 3.3 yrs; 58.4 ± 6.5 kg; 171.7 ± 9.0 cm) using a 10-camera motion capture system. Kinematic data were normalized to the gait cycle and were divided into sub-phases for analysis. Kinematic data of the first and last 10 WC strides were compared to identify short term kinematic adaptations (α=0.05). Neither computer task performance (p=0.071) nor walking velocity (p=0.089) was sacrificed during WC compared to SC and TW, respectively. Significant kinematic changes occurred in response to WC (p<0.05). Significant differences were identified between the first and last 10 WC strides (p<0.05), which revealed that some participants trended toward a return to normal gait as exposure to WC increased. Results suggest that active workstations do not diminish computing performance, and that walking safety is not sacrificed after initial exposure. We suggest gradual introduction to an active workstation, particularly if the computer task is challenging.
Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 2017
This study evaluated the effects of active versus static standing on short-duration computer task performance, postural risks and perceived pain, comfort and fatigue. A repeated measures, within-subjects study was conducted in which 16 participants performed 40 trials of a computer-based homing task in two active standing versus a static standing condition. Computer task performance was operationalized using mousing and typing speed as the measures; postural risk was evaluated using the Rapid Entire Body Assessment (REBA). Perceived scores for pain, comfort and fatigue were reported through a survey administered at baseline and after each standing task condition. Results suggest that for short-duration computer tasks, there was no significant difference in typing speed between active and static standing. However, mousing speed was significantly higher in static standing compared to a specific active standing condition. Overall levels of perceived pain, comfort and fatigue did not di...
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.
Proceedings of the 21st Congress of the International Ergonomics Association (IEA 2021), 2021
Background: Increasing standing and walking time has been proposed to mitigate the risk of musculoskeletal discomfort (MSD) associated with prolonged sitting. However, the duration, frequency, and timing of standing and walking required to reduce risk of MSD is less understood. Objective: The primary aim of this cross-sectional study was to 1) understand the relationship between daily movement patterns and MSD among office workers; and 2) determine whether daily movement patterns and MSD differed between those with different sitting strategies during prolonged work. Methods: 26 participants completed baseline questionnaires and wore an inertial measuring unit to quantify posture and movement over a 48-h period, stratified by work and leisure time. Participants were then classified as "breakers" and "prolongers" based on breaks taken during a 2-h sitting bout. The relationships between posture, movement and MSD were assessed using Spearman correlation coefficients, two-sample t tests, and Mann Whitney U tests, then stratified by and compared between breakers and prolongers. Results: Step count(r 2 = −0.26), standing time(r 2 = −0.39), and walking time(r 2 = −0.31) were negatively associated with MSD, whereas sitting duration was positively(r 2 = 0.20) associated with MSD; posture, activity, and MSD correlations were similar between work and leisure time. Prolongers(10.55(1.28)) spent more hours sitting compared to breakers(9.01(3.02)) and tended to have more overall MSD(p < 0.05). Conclusion: Increased time spent standing and walking while decreasing sitting time during both work and leisure time may help reduce risk of MSD. Those who did not change posture during the work bout tended to spend more time sitting and less time standing and walking during both work and leisure time. Future interventions should consider encouraging increased standing and walking during both work and leisure time to reduce MSD among office workers.
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.