Evaluating biomechanics of user-selected sitting and standing computer workstation

A standing computer workstation has now become a popular modern work place intervention to reduce sedentary behavior at work. However, user's interaction related to a standing computer workstation and its differences with a sitting workstation need to be understood to assist in developing recommendations for use and set up. The study compared the differences in upper extremity posture and muscle activity between user-selected sitting and standing workstation setups. Twenty participants (10 females, 10 males) volunteered for the study. 3-D posture, surface electromyography, and user-reported discomfort were measured while completing simulated tasks with each participant's self-selected workstation setups. Sitting computer workstation associated with more non-neutral shoulder postures and greater shoulder muscle activity, while standing computer workstation induced greater wrist adduction angle and greater extensor carpi radialis muscle activity. Sitting computer workstation also associated with greater shoulder abduction postural variation (90th–10th percentile) while standing computer workstation associated with greater variation for should rotation and wrist extension. Users reported similar overall discomfort levels within the first 10 min of work but had more than twice as much discomfort while standing than sitting after 45 min; with most discomfort reported in the low back for standing and shoulder for sitting. These different measures provide understanding in users' different interactions with sitting and standing and by alternating between the two configurations in short bouts may be a way of changing the loading pattern on the upper extremity.

Source: Lin, M. Y., Barbir, A., & Dennerlein, J. T. (2017). Applied Ergonomics.

Pre-existing low-back symptoms impact adversely on sitting time reduction in office workers

Objectives: Initiatives to reduce office-workplace sitting are proliferating, but the impact of pre-existing musculoskeletal symptoms on their effectiveness has not been determined. We assessed the influence of musculoskeletal symptoms on the outcomes of a workplace sitting intervention.
Methods: Baseline and 3-month data from a cluster-randomized controlled trial of a workplace sitting intervention (Stand Up Victoria; trial registration number ACTRN12611000742976) were used. Office workers (n = 231) from 14 work teams within one organisation were randomised (by worksite) to a multicomponent program with individual-, organisational-, and environmental-level (sit-stand workstations) change strategies; or, to a control condition (no intervention). Musculoskeletal symptoms in the low-back, upper and lower extremities (present/absent) were assessed through self-report. Linear regression models tested the moderation by baseline musculoskeletal symptoms of intervention effects on workplace sitting and standing time and on sitting and standing bout durations, assessed by the activPAL3™ activity monitor.
Results: There were significant reductions in sitting and increased standing at work (p < 0.05). However, effects varied significantly by the presence of pre-existing low-back (but not other) symptoms, with greater benefit being seen in those without symptoms. Effects on sitting time and sitting bout duration were weaker in those with low-back symptoms compared to those without by 34.6 [95% CI (0.9; 68.3)] min/8-h workday and 5.1 [95% CI (0.2; 9.9)] min, respectively. Comparable effects were seen for standing.
Conclusion: Low-back symptoms may impact on the extent to which office workers change their workplace sitting and standing time. A prudent next step to improve the effectiveness of workplace sitting-reduction initiatives such as Stand Up Victoria may be to assess and address the needs of those who displayed comparatively limited behaviour change, namely those with pre-existing low-back discomfort.

Source: Coenen, P., Healy, G. N., Winkler, E. A., Dunstan, D. W., Owen, N., Moodie, M., ... & Straker, L. M. (2017). International Archives of Occupational and Environmental Health, 1-10.

Reducing Office Workers' Sitting Time at Work Using Sit-Stand Protocols

Results From a Pilot Randomized Controlled Trial
Objective: To examine the effects of different sit-stand protocols on work-time sitting and physical activity (PA) of office workers.
Methods: Participants (n = 26, 77% women, mean age 42) were randomly allocated to usual sitting (control) or one of three sit-stand protocols (intervention) facilitated by height-adjustable workstations for a 4-week period between June and August 2015. Sitting, standing, and stepping time were assessed by inclinometry (activPAL); leisure-time physical activity (LTPA) by self-report. One-way analysis of covariance (ANCOVA) and post-hoc (Bonferroni) tests explored between-group differences.
Results: Compared with baseline, intervention groups reduced work sitting time by 113 minutes/8-hour workday (95% confidence interval [CI] [-147,-79]) and increased work standing time by 96 minutes/8-hour workday (95% CI [67,125]) without significantly impacting LTPA/sleep time.
Conclusions: Sit-stand protocols facilitated by height-adjustable workstations appear to reduce office workers' sitting time without significant adverse effects on LTPA.

Source: Li, I., Mackey, M. G., Foley, B., Pappas, E., Edwards, K., Chau, J. Y., ... & Winkler, E. (2017). Journal of Occupational and Environmental Medicine.

Development and validation of an easy-to-use risk assessment tool for cumulative low back loading

The Lifting Fatigue Failure Tool (LiFFT)
Recent evidence suggests that musculoskeletal disorders (MSDs) may be the result of a fatigue failure process in affected tissues. This paper describes a new low back exposure assessment tool (the Lifting Fatigue Failure Tool [LiFFT]), which estimates a “daily dose” of cumulative loading on the low back using fatigue failure principles. Only three variables are necessary to derive the cumulative load associated with a lifting task: the weight of the load, the maximum horizontal distance from the spine to the load, and the number of repetitions for tasks performed during the workday. The new tool was validated using two existing epidemiological databases: the Lumbar Motion Monitor (LMM) database, and a database from a U.S. automotive manufacturer. The LiFFT cumulative damage metric explained 92% of the deviance in low back disorders (LBDs) in the LMM database and 72–95% of the deviance in low back outcomes in the automotive database (depending on the outcome measure). Thus, LiFFT is practitioner friendly and its cumulative damage metric highly related to low back outcomes.

Source: Gallagher, S., Sesek, R. F., Schall, M. C., & Huangfu, R. (2017). Applied Ergonomics.

Les lombalgies liées au travail

Les lombalgies représentent aujourd'hui 20 % des accidents du travail : c'est le chiffre révélé par une étude inédite de l'Assurance Maladie - Risques professionnels. Le nombre des lombalgies d'origine professionnelle ne diminue pas depuis dix ans en dépit de la baisse de la sinistralité. Elles coûtent près d'un milliard d'euros par an, soit l'équivalent du coût des autres troubles musculo-squelettiques (TMS). Certains secteurs d'activité présentent un sur-risque en matière de lombalgie, comme les métiers d'aide et de soins à la personne et les activités logistiques.

Source: http://www.inrs.fr/actualites/lombalgies-travail.html

Effects on musculoskeletal pain from “Take a Stand!”

A cluster-randomized controlled trial reducing sitting time among office workers
The intervention in Take a Stand! was effective in reducing sitting time among office workers, additionally this study shows that pain in neck-shoulders was reduced after the 3-month intervention period. For other pain sites, there were no changes, but for total pain score there was a slight reduction. This is relevant as musculoskeletal pain is very common among office workers.

Source: Danquah, I. H., Kloster, S., Holtermann, A., Aadahl, M., & Tolstrup, J. S. (2017). Scandinavian Journal of Work, Environment & Health.

Évaluer les interventions de prévention des RPS - TMS

Ce guide pratique accompagne étape par étape les intervenants dans leur démarche d'évaluation. Il propose des apports méthodologiques sur l'évaluation, des exemples illustratifs et une grille regroupant les conséquences potentielles des démarches de prévention des risques psychosociaux (RPS) et trouble musculosquelettiques (TMS). Il est accompagné du " Document d'évaluation de mon intervention " que l'intervenant pourra renseigner au fur et à mesure de sa démarche.
La démarche proposée permet de mesurer un large éventail des effets qu'une intervention produit et de les analyser au regard des méthodes mises en oeuvre et de la singularité des contextes rencontrés. Elle permet ainsi de mettre en valeur toute la richesse, la diversité et la complexité des interventions de prévention. 

Source: http://www.inrs.fr/media.html?refINRS=CC%2018

Human Body Mechanics of Pushing and Pulling: Analyzing the Factors of Task-related Strain on the Musculoskeletal System

The purpose of this review is to name and describe the important factors of musculoskeletal strain originating from pushing and pulling tasks such as cart handling that are commonly found in industrial contexts. A literature database search was performed using the research platform Web of Science. For a study to be included in this review differences in measured or calculated strain had to be investigated with regard to: (1) cart weight/ load; (2) handle position and design; (3) exerted forces; (4) handling task (push and pull); or (5) task experience. Thirteen studies met the inclusion criteria and proved to be of adequate methodological quality by the standards of the Alberta Heritage Foundation for Medical Research. External load or cart weight proved to be the most influential factor of strain. The ideal handle positions ranged from hip to shoulder height and were dependent on the strain factor that was focused on as well as the handling task. Furthermore, task experience and subsequently handling technique were also key to reducing strain. Workplace settings that regularly involve pushing and pulling should be checked for potential improvements with regards to lower weight of the loaded handling device, handle design, and good practice guidelines to further reduce musculoskeletal disease prevalence.

Source: Argubi-Wollesen, A., Wollesen, B., Leitner, M., & Mattes, K. (2017). Safety and Health at Work, 8(1), 11-18.

Integration of active pauses and pattern of muscular activity during computer work

Submaximal isometric muscle contractions have been reported to increase variability of muscle activation during computer work; however, other types of active contractions may be more beneficial. Our objective was to determine which type of active pause vs. rest is more efficient in changing muscle activity pattern during a computer task. Asymptomatic regular computer users performed a standardised 20-min computer task four times, integrating a different type of pause: sub-maximal isometric contraction, dynamic contraction, postural exercise and rest. Surface electromyographic (SEMG) activity was recorded bilaterally from five neck/shoulder muscles. Root-mean-square decreased with isometric pauses in the cervical paraspinals, upper trapezius and middle trapezius, whereas it increased with rest. Variability in the pattern of muscular activity was not affected by any type of pause. Overall, no detrimental effects on the level of SEMG during active pauses were found suggesting that they could be implemented without a cost on activation level or variability.

Source: St-Onge, N., Samani, A., & Madeleine, P. (2017). Ergonomics.

Associations of objectively measured sitting and standing with low-back pain intensity

A 6-month follow-up of construction and healthcare workers
This study investigated associations between sitting and standing, respectively, and low-back pain with objectively measured exposures for several days and a prospective design. Sitting at work and during full-day is negatively associated with cross-sectional- and prospective low-back pain intensity. This association was seen for the healthcare sector, but not for the construction sector.

Source: Lunde, L. K., Koch, M., Knardahl, S., & Veiersted, K. B. (2017). Scandinavian Journal of Work, Environment & Health.

Guide aménagement d'un poste d'accueil

Ce guide de prévention vous aidera à concevoir un poste d’accueil sécuritaire et fonctionnel ou à corriger les déficiences d’un poste existant. Il propose une démarche d’aménagement d’un poste d’accueil en quatre étapes : l’analyse des besoins, 
l’élaboration d’un concept, l’élaboration des caractéris­tiques détaillées du poste et, finalement, la validation et le suivi.
À chacune des étapes, l’implication des personnes qui travailleront de près ou de loin au poste d’accueil est essentielle. Ces personnes pourront préciser la nature du travail qui y sera réalisé, exprimer leurs besoins et valider les choix retenus.

Source: http://asstsas.qc.ca/publication/guide-amenagement-dun-poste-daccueil-gp72

Neck posture during lifting and its effect on trunk muscle activation and lumbar spine posture

Neck and head posture have been found to have a significant influence on the posture of the lower spine region during lifting and both an extended/upward gaze and a flexed/downward gaze have been hypothesized to lead to increased pain and/or overuse of the neck musculature. As a result, strength training recommendations have turned to the use of a retracted neck posture as being the safer posture to assume during lifting. This study examined trunk and neck muscle activity and lumbar spine posture in seven participants while performing moderate load lifts using a retracted neck posture (chin drawn in posteriorly; recently gaining popularity among coaches, trainers, and physical therapists to reduce neck pain during lifting, and freestyle neck posture (no instructions given). The retracted neck resulted in less lumbar spine flexion and increased lumbar erector spinae, external oblique, and sternocleidomastoid activity. The retracted posture also resulted in decreased activity in the thoracic erector spinae and dorsal neck musculature. The increased trunk and sternocleidomastoid activity and decreased spine flexion observed in the seven participants of this study when lifting with a retracted neck may have the potential to help lower the risk of spine pain/injury.

Source: Hlavenka, T. M., Christner, V. F., & Gregory, D. E. (2017). Applied Ergonomics, 62, 28-33.

Total Worker Health® Concepts to Reduce the Health Risks from Sedentary Work

U.S. workplaces have become increasingly sedentary, with resulting negative health effects. Through its Total Worker Health® Program, the National Institute for Occupational Safety and Health (NIOSH) recommends an integrated approach to addressing sedentary work environments. An integrated approach is one that protects workers from work-related injury and illness and helps them advance their overall health and well-being, on and off the job. This document describes organizational practices that can reduce the risks associated with sedentary work.

Source: https://www.cdc.gov/niosh/docs/wp-solutions/2017-131/

Qualitative ergonomics/human factors research in health care

Current state and future directions
The objective of this systematic review was to understand the current state of Ergonomics/Human Factors (E/HF) qualitative research in health care and to draw implications for future efforts. This systematic review identified 98 qualitative research papers published between January 2005 and August 2015 in the seven journals endorsed by the International Ergonomics Association with an impact factor over 1.0. The majority of the studies were conducted in hospitals and outpatient clinics, were focused on the work of formal health care professionals, and were classified as cognitive or organizational ergonomics. Interviews, focus groups, and observations were the most prevalent forms of data collection. Triangulation and data archiving were the dominant approaches to ensuring rigor. Few studies employed a formal approach to qualitative inquiry. Significant opportunities remain to enhance the use of qualitative research to advance systems thinking within health care.

Source: Valdez, R. S., McGuire, K. M., & Rivera, A. J. (2017). Applied Ergonomics, 62, 43-71.

Implementing powered stretcher and load systems was a cost effective intervention to reduce the incidence rates of stretcher related injuries in a paramedic service

Paramedic services are considering moving towards the use of powered stretcher and load systems to reduce stretcher related injuries, but cost is perceived as a barrier. This study compared injury incidence rates, days lost, and compensation costs between Niagara Emergency Medical Service (NEMS) and Hamilton Paramedic Service (HPS) pre- (four years) and post- (one year) implementation of powered stretcher and load systems in NEMS. Prior to the intervention stretcher related musculoskeletal disorder (MSD) incidence rates averaged 20.0 (±6.8) and 17.9 (±6.4) per 100 full time equivalent (FTE), in NEMS and HPS respectively. One-year post intervention rates decreased to 4.3 per 100 FTE in NEMS, a 78% reduction. Rates modestly increased to 24.6 per 100 FTE in HPS in same period. Cost-benefit analysis estimated that the added cost to purchase powered stretcher and load systems would be recovered within their expected 7-year service life due to the reduction in compensation costs.

Source: Armstrong, D. P., Ferron, R., Taylor, C., McLeod, B., Fletcher, S., MacPhee, R. S., & Fischer, S. L. (2017). Applied Ergonomics, 62, 34-42.

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