Ergonomie : nouveautés 07/2018

ergonomie_0Voici les dernières publications repérées concernant l’ergonomie. En ergonomie de bureau, deux articles et une revue systématique abordent les interventions pour réduire le temps passé en posture assise et un autre porte sur le travail à l’écran. Deux articles étudient l’effet d’exosquelettes sur le corps lors de différents types de tâches et deux autres se penchent sur la biomécanique et les risques lors de tâches de manutention de charges. Enfin, les articles sur l’organisation des tâches et du temps de travail incluent une étude sur la rotation des tâches et plusieurs sur les horaires de travail (travail par quarts, travail de nuit et temps supplémentaire). Consultez-les par sujet :

Ergonomie de bureau
Manutention de charges
Organisation des tâches
Organisation du temps de travail

Ergonomie de bureau

Blood Pressure Response to Interrupting Workplace Sitting Time With Non-Exercise Physical Activity: Results of a 12-month Cohort Study91px-Lock-blue.svg Source : Journal of Occupational and Environmental Medicine Prépublication, juin 2018

This study evaluated the blood pressure (BP) effects of a yearlong e-health solution designed to interrupt prolonged occupational sitting time. BP data of 228 desk-based employees (45.1 ± 10.5 years) were analyzed at baseline, 3, 6, 9, and 12 months. Participants used the e-health solution 5.5 ± 2.0 times/day in the first 3 months which reduced to 4.2 ± 2.5 times/day by the end of the study (P < 0.05). Authors conlclude that the e-health solution designed to increase non-exercise physical activity by interrupting sitting time in the workplace is feasible and produced long-term reductions in blood pressure.

Visual and psychological stress during computer work in healthy, young females—physiological responses Source : International Archives of Occupational and Environmental Health Prépublication, mai 2018

Among computer workers, visual complaints, and neck pain are highly prevalent. This study explores how occupational simulated stressors during computer work, like glare and psychosocial stress, affect physiological responses in young females with normal vision. The study was a within-subject laboratory experiment with a counterbalanced, repeated design. Forty-three females performed four 10-min computer-work sessions with different stress exposures: (1) minimal stress; (2) visual stress (direct glare); (3) psychological stress; and (4) combined visual and psychological stress. Psychological stress induced a transient increase in trapezius muscle activity and a more forward-bent posture. Bending forward towards the computer screen was correlated with higher productivity (reading speed), indicating a concentration or stress response. Forward bent posture was also associated with changes in fixation disparity. Furthermore, during computer work per se, trapezius muscle activity and blood flow, orbicularis oculi muscle blood flow, and heart rate were increased compared to rest.Exposure to glare and psychological stress during computer work were shown to influence the trapezius muscle, posture, and blink rate in young, healthy females with normal binocular vision, but in different ways. Accordingly, both visual and psychological factors must be taken into account when optimizing computer workstations to reduce physiological responses that may cause excessive eyestrain and musculoskeletal load.

Effects of standing on typing task performance and upper limb discomfort, vascular and muscular indicators Source : Applied Ergonomics 72, octobre 2018

Standing is a popular alternative to traditionally seated computer work. However, no studies have described how standing impacts both upper body muscular and vascular outcomes during a computer typing task. Twenty healthy adults completed two 90-min simulated work sessions, seated or standing. Upper limb discomfort, electromyography (EMG) from eight upper body muscles, typing performance and neck/shoulder and forearm blood flow were collected. Results showed significantly less upper body discomfort and higher typing speed during standing. Lower Trapezius EMG amplitude was higher during standing, but this postural difference decreased with time (interaction effect), and its variability was 68% higher during standing compared to sitting. There were no effects on blood flow. Results suggest that standing computer work may engage shoulder girdle stabilizers while reducing discomfort and improving performance. Studies are needed to identify how standing affects more complex computer tasks over longer work bouts in symptomatic workers.

Workplace interventions for reducing sitting at workRessource en accès restreint (acheter à l'éditeur ou demandez un prêt entre bibliothèques) Source : Cochrane Database of Systematic Reviews Prépublication, juin 2018

Time spent sitting and being physically inactive at work has increased in recent decades. Long periods of sitting may increase the risk of obesity, heart disease, and premature death. It is unclear whether interventions that aim to reduce sitting at workplaces are effective. This review aimed to find out the effects of interventions aimed at reducing sitting time at work. We searched the literature in various databases up to 9 August 2017. We found 34 studies conducted with a total of 3,397 employees from high-income countries. They tested physical changes in the workplace design and environment, changes in workplace policies, information and counselling interventions, and multi-category interventions. At present there is low-quality evidence that sit-stand desks may reduce sitting at work in the first year of their use. However, the effects are likely to reduce with time. There is generally insufficient evidence to draw conclusions about such effects for other types of interventions and for the effectiveness of reducing workplace sitting over periods longer than one year. More research is needed to assess the effectiveness of different types of interventions for reducing sitting at workplaces, particularly over longer periods.


The effect of a passive trunk exoskeleton on functional performance in healthy individuals Source : Applied Ergonomics 72, octobre 2018

The objective of this study was to assess the effect of a passive trunk exoskeleton on functional performance for various work related tasks in healthy individuals. 18 healthy men performed 12 tasks. Wearing the exoskeleton tended to increase objective performance in static forward bending, but decreased performance in tasks, such as walking, carrying and ladder climbing. A significant decrease was found in perceived task difficulty and local discomfort in the back in static forward bending, but a significant increase of perceived difficulty in several other tasks, like walking, squatting and wide standing. Especially tasks that involved hip flexion were perceived more difficult with the exoskeleton. Design improvements should include provisions to allow full range of motion of hips and trunk to increase versatility and user acceptance.

Elongation of the surface of the spine during lifting and lowering, and implications for design of an upper body industrial exoskeleton Source : Applied Ergonomics 72, octobre 2018

The aim of this study was to assess the elongation of the skin surface of the spine for simulated industrial lifting and lowering tasks to aid the design of industrial exoskeletons worn on the back. Eighteen male participants lifted and lowered a box of varying loads using three techniques. Motion capture sensors attached to the spine from C7 to S1 measured movement. Stoop lifting involved significantly more elongation than squat lifting. Load and Task (lift vs. lower) did not have a significant effect on elongation. Elongation of the skin surface of the lumbar spine was greater than for the thoracic spine. These data detail example levels of elongation of the skin surface of the spine, which should be considered in upper body wearable industrial exoskeleton design. Further, exoskeleton design should take into account that the skin surface of the lumbar spine involves greater elongation than the skin surface of the thoracic spine during deep lifting.

Manutention de charges

How does the biomechanical exposure of the upper body in manual box handling differ from exposure in other tasks in the real industrial context? Source : International Journal of Industrial Ergonomics 68, novembre 2018

The assessment of biomechanical exposure during handling tasks in relation to other activities that are performed in industrial settings can be crucial to understand the biomechanical demands of manual box handling for the upper limbs. This study aims to evaluate the representativeness of the handling task to the upper body in comparison with the other tasks in a real setting, compare the biomechanical exposure between tasks, and identify the differences in exposure during manual box handling from job exposure. Twelve workers had biomechanical exposure assessed through trapezius muscle activity and posture recordings (upper back and upper arms) during 4h of a regular working day. Handling tasks demonstrated the highest biomechanical demand to the upper body, particularly for peak loads of the upper trapezius activation and upper back forward flexion postures. However, handling tasks were also associated with a high exposure variation. Interventions aiming to decrease loads in handling tasks can be relevant to decreasing peak loads and avoiding musculoskeletal disorders on the upper limbs.

Surface electromyography for risk assessment in work activities designed using the “revised NIOSH lifting equation” Source : International Journal of Industrial Ergonomics 68, novembre 2018

The aims of this study were: to identify surface electromyography (sEMG)-based indices of trunk muscles acquired during the execution of lifting tasks designed using the revised NIOSH lifting equation and featuring a progressively increasing lifting index (LI); to study changes of these indices in relation to the LI; to evaluate the relationship between the identified indices and forces ( F L 5 − S 1 ) and moments ( M L 5 − S 1 ) at the L5-S1 joint. sEMG, kinematic and kinetic data of 20 male workers were recorded in three conditions. We computed the average rectified value (ARV), root mean square (RMS) and maximum value (Max) of twelve trunk muscles and the muscle co-activation. We also estimated F L 5 − S 1 and M L 5 − S 1 . One-way repeated-measures ANOVA and post-hoc analysis showed that sEMG-based indices values increased with LI increment of 1 (LI = l, 2 and 3). sEMG and kinetic parameters were linearly correlated. Findings suggest a promising use of wearable sEMG sensors in developing instrumental-based risk assessment tools in either the laboratory or workplace. In fact, some indices discriminate the investigated risk levels and correlate with the variables that generate the damage.

Organisation des tâches

The influence of job rotation and task order on muscle responses in females Source : International Journal of Industrial Ergonomics 68, juin 2018

Job rotation aims to reduce muscle fatigue by switching between functionally different tasks to theoretically lessen the risk of site-specific fatigue and work-related musculoskeletal disorders (WMSDs). Rotating between two functionally different tasks, continuing a single task, and varying task order were assessed in the present study for influence on muscle fatigue indicators in a female population. Indications of fatigue were limited in the results. Forward flexion and internal rotation maximum voluntary force declined in all task combinations while ratings of perceived exertion (RPE) increased; non-rotating task combinations had the greatest declines in force and increases in RPE. Changes in aEMG were, however, too small to distinguish an order effect. The EMG results suggest muscular demand overlap between the two tasks, despite being functionally different. The effectiveness of job rotation is partially dependent on selecting tasks that engage distinct muscle groups.

Organisation du temps de travail

Association between shiftwork and the risk of colorectal cancer in females: a population-based case–control study Source : Occup Environ Med 75(5), mai 2018

Research indicates that shiftwork may be associated with increased risks of adverse health outcomes, including some cancers. However, the evidence of an association between shiftwork and colorectal cancer risk is limited and inconclusive. We investigated the association between two types of shiftwork (graveyard shiftwork and early-morning shiftwork) and six mechanistic shiftwork variables (including light at night and phase shift) and the risk of colorectal cancer among females in an Australian population-based case–control study. No evidence of an increased risk of colorectal cancer among females who had worked in occupations involving shiftwork was observed in this study.

Night shift work and breast cancer risk: what do the meta-analyses tell us? Source : Scandinavian Journal of Work, Environment & Health Prépublication, mai 2018

This short communication examines the collective results from several recently published meta-analyses of night shift work and breast cancer risk. By summarizing and assessing the quality of these studies, opportunities for future epidemiologic research were identified along with the possible implications of meta-analyses on further evaluations of shift work with respect to breast cancer risk.

Mortalité prématurée par maladies cardiovasculaires chez les femmes selon la catégorie sociale et le secteur d’activité : synthèse Source : Santé publique France, juin 2018

Les maladies cardiovasculaires (MCV) sont moins bien documentées chez les femmes que chez les hommes. Les principaux déterminants socioprofessionnels établis dans la littérature scientifique sont les risques psychosociaux, le travail de nuit, le travail posté, les horaires atypiques, et les bruits nocifs. La mortalité prématurée par maladies cardiovasculaires diminue entre 1976 et 2002 et présente un gradient social croissant des cadres vers les ouvrières et de sdifférences selon les secteurs. Les secteurs professionnels les plus à risque, notamment l’hôtellerie-restauration et l’industrie manufacturière, pourraient être particulièrement ciblés par les actions de prévention, avec une attention encore plus grande aux catégories les plus défavorisées.

Nursing overtime : should it be regulated? Source : AOHP Journal 38(2), juin 2018

Nursing overtime is common in health care to accommodate staffing needs despite evidence that it increases the incidence of patient and nurse adverse events. Some states have been successful in implementing overtime regulation; however, attempts at the federal level remain unsuccessful.

Effects of night-time on-call work on heart rate variability before bed and sleep quality in visiting nurses Source : International Archives of Occupational and Environmental Health Prépublication, juin 2018

In Japan, many visiting nurses work carrying cell phones to respond to calls from users even at night (on-call work). This study investigated whether on-call work affected heart rate variability (HRV) before bed and decreased sleep quality in visiting nurses even if their sleep was not interrupted due to actual calls. Nurses were asked to record their 2.5-min resting HRV before bed, and to undergo one-channel sleep electroencephalography (EEG) and subjective sleep evaluations upon waking at home for 4–5 consecutive days, including both on-call and non-on-call days. The study found no differences in HRV measures and objective sleep EEG variables. A significant increase in “sleepiness on rising” and a decrease in “feeling refreshed” were observed on on-call days, and younger subjects demonstrated a significant reduction in “sleepiness on rising”. Authors conclude that adverse effects of on-call work on sleep quality in most visiting nurses are thought to be subjective, and relatively young nurses tend to notice a decrease in sleep quality. On-call work itself does not appear to be a substantial stressor that could affect HRV and sleep structure.


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