Quebec Serve and Protect Low Back Pain Study: What About Mental Quality of Life?

Background
As of now, the impact of low back pain (LBP) and its chronic state, chronic low back pain (CLBP), on mental health-related quality of life (HRQOL) has never been investigated among police officers. The present investigation aims at studying this relationship using a biopsychosocial model.
Methods
Between May and October 2014, a Web-based cross-sectional study was conducted among Quebec police officers (Quebec, Canada). Mental HRQOL was measured using the role emotional (RE) and the mental health (MH) domains of the SF-12v2 Health Survey. The impact of CLBP on mental HRQOL (as opposed to acute/subacute LBP or no LBP) was studied with a multivariate linear regression model.
Results
Of the 3,589 police officers who participated in the study, 1,013 (28.4%) reported CLBP. The mean age of respondents was 38.5 ± 8.7 years, and 32.0% were females. The RE (44.1/100) and MH (49.0/100) mean scores of the CLBP group were comparable with the scores found in populations suffering from cancer or heart diseases. Compared to officers without LBP, the presence of CLBP was significantly associated with lower RE (β: −0.068; p = 0.003) and MH (β: −0.062; p = 0.002) scores. These relationships were not found in the acute/subacute LBP group.
Conclusion
Our results underscore how frequent CLBP is among police officers and how burdensome it is. Considering the importance of good physical and mental health for this occupational population, police organizations should be aware of this issue and contribute to the efforts toward CLBP prevention and management in the workplace.

Source : Douma, N.B., Côté, C. et Lacasse, A. (2019). Safety and Health at Work, 10, (1), 39-46. https://doi.org/10.1016/j.shaw.2018.08.006

Caractéristiques socioprofessionnelles, reconnaissance en maladie professionnelle et devenir fonctionnel et professionnel de patients opérés d’un syndrome du canal carpien en Île-de-France (2009-2012)

Points clés

  •  Cette étude menée par Santé publique France en partenariat avec le Réseau Prévention Main Île-de-France (IdF), chez des patients opérés d'un syndrome du canal carpien (SCC), décrit les caractéristiques socio-professionnelles (CSP, déclaration en maladie professionnelle…) des patients et leurs liens avec la durée d'arrêt de travail.
  •  Parmi les patients en activité au cours des 10 ans précédant l'intervention, 59 % considéraient leur travail comme cause probable principale du SCC. Mais seuls 25 % des patients salariés avaient effectué une demande de reconnaissance en maladie professionnelle (MP).
  •  La durée médiane d'arrêt de travail chez les salariés en emploi était de 30 jours, variant de 21 jours pour les non-manuels à 40 jours pour les manuels lourds.
  •  La durée d'arrêt de travail était plus longue chez les patients ayant réalisé une déclaration en MP que chez les autres patients salariés (durée médiane de 44 jours contre 30 jours).
  •  Elle était plus longue également chez les patients soumis à un job strain, manipulant ou portant souvent au travail des charges de plus de 4 kg ou utilisant des outils vibrants en dehors du travail.
  •  Pour favoriser le retour au travail des patients opérés d'un SCC en IdF, la prévention devrait viser à réduire les expositions professionnelles telles que le port de charges ou les situations de job strain.
  •  L'augmentation de la durée d'arrêt de travail liée à la déclaration en MP justifie une attention particulière pour le retour au travail, avec une plus grande synergie entre les services de santé au travail, les soignants, l'assurance maladie et les employeurs.

Source : http://invs.santepubliquefrance.fr/Publications-et-outils/Rapports-et-syntheses/Travail-et-sante/2019/Caracteristiques-socioprofessionnelles-reconnaissance-en-maladie-professionnelle-et-devenir-fonctionnel-et-professionnel-de-patients-operes-d-un-syndrome-du-canal-carpien-en-Ile-de-France-2009-2012

 

Acceptation des exosquelettes par les opérateurs : étude exploratoire

L'introduction des exosquelettes, comme toute nouvelle technologie, constitue un changement au niveau de l'organisation et de l'activité des opérateurs. C'est dans ce cadre qu'est abordée la question spécifique de l'acceptabilité et de l'acceptation de ces dispositifs par les opérateurs. Pour cela, un questionnaire a été élaboré et administré à des utilisateurs, anciens utilisateurs et nonutilisateurs d'exosquelettes.
En termes de santé et sécurité, les résultats préliminaires présentés permettent de recueillir des informations sur la qualité de l'interaction opérateur-exosquelette, d'identifier des points bloquants et/ou facilitateurs de l'usage de ces dispositifs et d'envisager certains facteurs de risques psychosociaux, physiques et accidentels chez les utilisateurs.

Source: http://www.rst-sante-travail.fr/rst/pages-article/ArticleRST.html?ref=RST.TF%20264

Acquisition et intégration d'un exosquelette en entreprise

Ce guide, destiné aux préventeurs, permet à l'entreprise d'appréhender les nombreuses questions posées par l'intégration d'un exosquelette. Il propose une démarche allant de la définition du besoin d'assistance physique jusqu'à son intégration en situation réelle de travail.
Structurée en trois phases, cette méthode vise à accompagner l'entreprise dans sa réflexion d'acquisition d'un exosquelette, à créer les conditions permettant son intégration dans la situation de travail et à évaluer les usages de l'exosquelette au cours du temps.

Source : http://www.inrs.fr/media.html?refINRS=ED%206315

Troubles musculo-squelettiques et facteurs psychosociaux au travail

Ce rapport présente l'état des connaissances scientifiques sur la façon dont les facteurs psychosociaux influencent les troubles musculo-squelettiques (TMS). Il analyse l'impact des TMS sur l'aptitude au travail et la qualité du travail. Près de 40 millions de travailleurs en Europe souffrent de TMS des membres et du dos, ce qui en fait la maladie professionnelle la plus répandue dans l'UE. L'objectif de ce rapport est d'influencer les efforts d'intervention et de fournir des recommandations scientifiquement fondées pour améliorer la santé des travailleurs européens

Source : https://www.etui.org/fr/Publications2/Rapports/Troubles-musculo-squelettiques-et-facteurs-psychosociaux-au-travail

 

Work-related Musculoskeletal Disorders, a tri-sector exploration

High rates of WRMSD-related sick leave put pressure on employers and businesses, hitting their bottom lines and potentially leading to understaffing, reduced productivity and lower staff morale. Directly affected workers not only suffer pain but also consequences that can be felt across their working, home and social lives.
The construction, healthcare and transportation and storage industries were selected as the focus of this research because they have significantly higher rates of WRMSDs compared with the average rate for all industry. Qualitative research was commissioned to:
- Explore what employers and workers knew about WRMSDs and regulation.
- Explore employers' attitudes and perceptions of WRMSDs, their approaches to prevention and management and what was limiting engagement with health and safety issues.
- Explore the journeys of workers and how they have managed health challenges in relation to WRMSDs.
- Uncover the needs of ‘both sides' to highlight barriers and opportunities regarding future intervention, communication and campaign strategies.
- Understand current workplace practice and inspire improvements in WRMSD prevention and management.

Source: http://www.hse.gov.uk/research/insight/msd-report.pdf

Mechanical and psychosocial work exposures: the construction and evaluation of a gender-specific job exposure matrix (JEM)

Objectives: The aim of this study was to (i) construct and evaluate a gender-specific job exposure matrix (JEM) for mechanical and psychosocial work exposures and (ii) test its predictive validity for low-back pain.
Methods: We utilized data from the Norwegian nationwide Survey of Living Conditions on work environment in 2006 and 2009. We classified occupations on a 4-digit level based on the Norwegian version of the International Standard Classification of Occupations (ISCO-88). The mechanical and psychosocial exposure information was collected by personal telephone interviews and included exposures that were known risk factors for low-back pain. We evaluated the agreement between the individual- and JEM-based exposure estimates, with kappa, sensitivity and specificity measures. We assessed the JEM's predictive validity by testing the associations between low-back pain and the individual- and JEM-based exposure.
Results: The results showed an overall fair-to-moderate agreement between the constructed JEM and individual work exposures. The JEM performed considerably better for mechanical work exposures compared with psychosocial work exposures. The predictive validity of the mechanical and psychosocial JEM showed a consistently lower but predominantly reproducible association with low-back pain for both genders.
Conclusions: The mechanical estimates and psychosocial stressors, such as psychological demands, monotonous work and decision latitude in the constructed JEM, may be useful in large epidemiological register studies. The predictive validity of the matrix was evaluated as being overall acceptable and can be an effective and versatile approach to estimate the relationship work exposures and low-back pain.

Source: Hanvold, T. N., Sterud, T., Kristensen, P. et Mehlum, I. S. (2018). Scandinavian Journal of Work, Environment & Health.
http://dx.doi.org/10.5271/sjweh.3774

Exosquelettes au travail : impact sur la santé et la sécurité des opérateurs état des connaissances

Ce guide, destiné aux préventeurs, fait un point sur les connaissances actuelles des exosquelettes afin de mettre en évidence les intérêts et les limites de leur usage en matière de prévention des troubles musculosquelettiques (TMS).
L'objectif est d'aider à mieux appréhender l'impact des exosquelettes pour accompagner efficacement l'entreprise dans sa démarche d'acquisition et d'intégration d'un exosquelette.

Source: http://www.inrs.fr/media.html?refINRS=ED%206311

Musculoskeletal disorders of agricultural workers in the greenhouses of Almería (Southeast Spain)

In southeast Spain (Almería), we find the highest concentration of greenhouse crops in Europe, an agricultural sector that directly employs 55,000 people. The objective of this research was to evaluate the musculoskeletal working conditions of greenhouse workers through the standardized Nordic questionnaire. This questionnaire presents 28 multiple choice questions referring to different parts of the body. A total of 1002 questionnaires were completed, and information was collected on nine socio-demographic variables for each worker: sex, age, height, weight, surface area, cultivation, staking, greenhouse and nationality. Although the results show a high overall rate of symptoms of musculoskeletal disorders (MSDs), these findings do not mean that the workers are unable to perform agricultural tasks.

Source: López-Aragón, L., López-Liria, R., Callejón-Ferre, Á. J. et Pérez-Alonso, J. (2018). Safety Science, 109, 219-235.
https://doi.org/10.1016/j.ssci.2018.05.023

Acute Effects of Interrupting Sitting on Discomfort and Alertness of Office Workers

Objective: The aim of this study was to compare the effect of 4 hours of sitting interrupted with hourly bouts of standing and/or pedaling versus uninterrupted sitting on alertness and discomfort among sedentary office workers.
Methods: Fifteen middle-aged sedentary workers were randomized to three 4-hour conditions: (1) uninterrupted sitting; (2) sitting interrupted with 10 minutes of standing/hour; and (3) sitting interrupted with 10 minutes of pedaling/hour. Self-reported measures of alertness and discomfort were collected.
Results: Uninterrupted sitting significantly increased discomfort (P < 0.001). Discomfort was lower in both the standing (P < 0.001) and pedaling (P < 0.001) conditions than the uninterrupted sitting condition. Short-lived improvements in alertness were observed immediately following several standing (50%) and pedaling (100%) interruptions.
Conclusion: Prolonged sitting increases discomfort while brief standing and pedaling interruptions attenuate impairments in discomfort among sedentary workers.

Source: Benzo, R. M., Kruse, N. T., Hughes, W. E., Casey, D. P. et Carr, L. J. (2018). Journal of occupational and environmental medicine, 60(9), 804-809.
http://dx.doi.org/10.1097/JOM.0000000000001329

Participatory organizational intervention for improved use of assistive devices in patient transfer

A single-blinded cluster randomized controlled trial
Objectives: This randomized controlled trial (RCT) evaluated the effect of a participatory organizational intervention for improved use of assistive devices (AD) in patient transfer.
Methods: We randomly allocated 27 departments from five hospitals in Denmark to a participatory intervention (14 clusters, 316 healthcare workers) or a control group (13 clusters, 309 healthcare workers). The intervention consisted of 2×2 hour workshops with managers, the hospital's health and safety staff, and 2–5 healthcare workers from each department. Based on an assessment of barriers and solutions conducted prior to randomization, participants developed an action plan for implementing department-specific solutions for improving the use of AD. Use of necessary AD (using digital counters as primary outcome), and general use of AD (using accelerometers as secondary outcome), pain intensity in the low-back, work-related back injuries during patient transfer, and communication and guidance in the use of AD were measured at baseline, 6 and 12 months.
Results: Use of necessary AD (primary outcome), low-back pain, and back injuries did not change in the intervention compared with control group at 12-month follow-up. However, general use of AD measured with accelerometers as well as communication and guidance improved significantly in the intervention versus control group.
Conclusion: The intervention did not result in more frequent use of the necessary AD but led to more general use of AD, as well as increased communication and guidance.

Source: Jakobsen, M. D., Aust, B., Kines, P., Madeleine, P. et Andersen, L. L. (2018). Scandinavian Journal of Work, Environment & Health.
http://dx.doi.org/10.5271/sjweh.3769

Ergonomic interventions for preventing work-related musculoskeletal disorders of the upper limb and neck among office workers

Work-related upper limb and neck musculoskeletal disorders (MSDs) are one of the most common occupational disorders worldwide. Studies have shown that the percentage of office workers that suffer from MSDs ranges from 20 to 60 per cent. The direct and indirect costs of work-related upper limb MSDs have been reported to be high in Europe, Australia, and the United States. Although ergonomic interventions are likely to reduce the risk of office workers developing work-related upper limb and neck MSDs, the evidence is unclear. This is an update of a Cochrane Review which was last published in 2012.

Source: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD008570.pub3/full

Évaluation des processus : comprendre comment le contexte des entreprises influence le déroulement des premières étapes d’interventions ergonomiques

Bien qu'il soit généralement convenu que les ergonomes adaptent leur intervention au contexte de chaque entreprise, la façon précise dont ils y parviennent et sur quels critères cette adaptation se base sont peu renseignés au plan scientifique. Une évaluation des processus a été réalisée en adoptant un devis d'étude de cas multiple, en vue d'identifier les indicateurs de contexte ayant influencé quatre interventions du courant de l'ergonomie de l'activité, réalisées par des ergonomes en formation. L'évaluation a porté sur les étapes de l'intervention précédant l'implantation des changements, soit de l'analyse de la demande jusqu'au moment où le plan d'action est convenu avec les acteurs-clés. La collecte des données a été effectuée grâce à un journal de bord, des documents produits dans le cadre de l'intervention, ainsi que des entretiens avec les intervenants et les acteurs-clés impliqués dans l'intervention. Nos résultats présentés sous forme de modèles logiques font ressortir 12 indicateurs de contexte ayant représenté des leviers ou des obstacles au déroulement de l'intervention ou au plan d'action. Des combinaisons d'indicateurs ont eu un effet synergique positif ou négatif sur les cas. Le modèle d'évaluation proposé dans cette étude interdisciplinaire pourrait être repris lors d'études subséquentes pour bonifier la compréhension de l'influence du contexte dans d'autres situations d'interventions ergonomiques.

Source: Albert, V., Vézina, N., Bilodeau, H. et Coutarel, F. (2018). Activités, (15-2).
https://journals.openedition.org/activites/3411

Intégration de la préparation physique dans l’approche ergonomique

Quel dispositif pour quel(s) objectif(s)?
L'article présente un cas d'intervention ergonomique proposant la préparation physiologique des ouvriers comme levier de prévention des Troubles Musculo-Squelettiques dans le secteur agroalimentaire. Dans une entreprise dont les activités présentent de fortes contraintes organisationnelles et physiologiques, la place des marges de manœuvre dans un tel dispositif est questionnée. La mise en œuvre d'échauffements au sein d'une entreprise nécessite d'une part de disposer de compétences tant ergonomiques que sur la préparation physiologique. D'autre part, l'intégration des échauffements, forme de préparation physiologique ici mise en œuvre, imposerait une construction sociale spécifique de l'intervention. Enfin, les conditions de réussite du projet tant du point de vue des intervenants que de l'entreprise devraient être posées au préalable afin de garantir le succès du dispositif global de prévention.

Source: Uguen, C., Sablon, S. et Carballeda, G. (2018). Activités, (15-2).
https://journals.openedition.org/activites/3537

Intervention, conception et transformations : comment construire une prévention durable des TMS

Cet article a pour but de participer aux réflexions sur le rôle de l'ergonome dans l'intervention en entreprise. Il présente une intervention-formation relative à la prévention de la pénibilité et des TMS au travail. Cette intervention, menée comme une conduite de projet, s'est basée sur l'adoption de principes fondamentaux pour l'ergonomie dite centrée sur l'activité (Daniellou & Rabardel, 2005). Ces principes portent sur (1) la conception et la pérennisation des démarches de prévention durable, (2) la conduite et l'efficacité des interventions en ergonomie. Sur la base de ce corps de connaissances et de nos pratiques d'intervention antérieures, nous postulons que la mobilisation des acteurs et la transformation des représentations/perceptions sur le travail et la santé participent à l'augmentation du pouvoir d'agir des acteurs en matière de prévention. Ces principes sont illustrés et discutés à partir des résultats d'une intervention menée dans un abattoir de canards.

Source: Ciccone, E., Cuvelier, L., Decortis, F. et Bationo-Tillon, A. (2018). Activités, (15-2).
https://journals.openedition.org/activites/3450

Recurrent back pain during working life and exit from paid employment

A 28-year follow-up of the Whitehall II Study
Objectives To examine the impact of recurrent, as compared with single, reports of back pain on exit from paid employment over decades of follow-up.
Methods The study sample was from the British Whitehall II Study cohort (n=8665, 69% men, aged 35–55 at baseline), who had provided information about their reports of back pain between 1985 and 1994. Data about exit from paid employment (health-related and non-health related exit, unemployment and other exit) were collected between 1995 and 2013. Repeated measures logistic regression models were fitted to examine the associations, and adjust for covariates.
Results Recurrent pain was reported by 18% of participants, while 26% reported pain on an occasion and 56% did not report pain. Report of back pain on an occasion was not associated with health-related job exit, whereas recurrent pain was associated with such an exit (OR 1.51; 95% CI 1.15 to 1.99), when compared with those who did not report pain. These associations were somewhat stronger among middle-grade and lower-grade employees, while these associations were not seen among higher-grade employees. Differences in associations by age and psychosocial working conditions were small.
Conclusions These results highlight the need for early detection of recurrent back pain to prevent exit out of paid employment for health reasons. As the risk varies by occupational grade, this emphasises the importance of identification of high-risk groups and finding ways to address their modifiable risk factors.

Source: Lallukka, T., Mänty, M., Cooper, C., Fleischmann, M., Kouvonen, A., Walker-Bone, K. E., ... et Halonen, J. I. (2018). Occupational & Environmental Medicine, 75(11), 786-791.
http://dx.doi.org/10.1136/oemed-2018-105202

Démarche multidisciplinaire appliquée à l’analyse d’une activité dans un environnement dynamique

La conduite de véhicules légers à La Poste pour la distribution du courrier et des colis
Activité complexe différente de la conduite personnelle, la conduite professionnelle de véhicules légers prend une importance croissante dans le secteur de la livraison/messagerie confronté aux nouveaux modes de consommation. Peu étudiés, les risques pour la santé autres que les accidents de la route ont été approchés dans une étude exploratoire multidisciplinaire menée en collaboration avec le groupe La Poste. Son objectif a été d'explorer, en situation de travail, les différentes composantes de l'activité de distribution de courrier/colis, et particulièrement l'activité de conduite comme partie structurante de l'activité de distribution. La démarche méthodologique alliant des analyses ergonomiques et une approche médicale a mis en évidence des contraintes ainsi que des plaintes en relation principalement avec les caractéristiques des tournées de distribution. Ces résultats ont permis d'orienter la construction d'une étude épidémiologique visant à analyser les facteurs de risque spécifiques à la conduite de véhicules légers dans les activités de distribution.

Source: Hella, F., Radauceanu, A., Atain-Kouadio, J. J., Payet, R. et Colin, R. (2018). Perspectives interdisciplinaires sur le travail et la santé, (20-2).
https://journals.openedition.org/pistes/5733

Bi-directional relation between effort-reward imbalance and risk of neck-shoulder pain

Assessment of mediation through depressive symptoms using occupational longitudinal data
Objectives: Bi-directional associations between perceived effort?reward imbalance (ERI) at work and neckshoulder pain have been reported. There is also evidence of associations between ERI and depressive symptoms, and between depressive symptoms and pain while the links between ERI, depressive symptoms and pain have not been tested. We aimed to assess whether depressive symptoms mediate the association between ERI and neck-shoulder pain, as well as the association between neck-shoulder pain and ERI.
Methods: We used prospective data from three consecutive surveys of the Swedish Longitudinal Occupational Survey of Health (SLOSH) study. ERI was assessed with a short version of the ERI questionnaire, and pain was defined as having had neck-shoulder pain that affected daily life during the past three months. Depressive symptoms were assessed with a continuous scale based on six-items of the (Hopkins) Symptom Checklist. Counterfactual mediation analyses were applied using exposure measures from 2010/2012 (T1), depressive symptoms from 2012/2014 (T2), and outcomes from 2014/2016 (T3), and including only those free of outcome at T1 and T2 (N=2876?3239).
Results: ERI was associated with a higher risk of neck-shoulder pain [risk ratio (RR) for total effect 1.24, 95% confidence interval (CI) 1.02–1.50] and 40% of this total effect was mediated through depressive symptoms.
Corresponding RR for association between neck-shoulder pain and ERI was 1.36 (95% CI 1.13–1.65), but the mediating role of depressive symptoms was less consistent.
Conclusions: Depressive symptoms appear to be an intermediate factor in the relationship between ERI and neck-shoulder pain.

Source: Halonen, J. I., Lallukka, T., Virtanen, M., Rod, N. H. et Hanson, L. L. M. (2018). Scandinavian Journal of Work, Environment & Health.
http://dx.doi.org/10.5271/sjweh.3768

Comorbid symptoms of depression and musculoskeletal pain and risk of long term sickness absence

Background: Symptoms of depression and musculoskeletal pain have both been found to be associated with increased risk of long term sickness absence (LTSA). The comorbidity between depression and pain i.e. simultaneous presence of both symptoms, is well established in the literature. The aim for the current investigation was to investigate whether the presence of comorbid pain influences the associations between depressive symptoms and LTSA or if the presence of comorbid depressive symptoms influences associations between musculoskeletal pain and LTSA.
Methods: A sample of 6572 Danish female health care workers responding to a questionnaire about health and working conditions were followed up in a national register of social transfer payments (DREAM) for 550 days. We estimated the risk for LTSA of four weeks or more, associated with depressive symptoms and number of musculoskeletal pain locations using a Cox proportional hazards model allowing multiple observations per individual. We conducted a test for multiplicative interaction between musculoskeletal pain locations and depressive symptoms, and presented stratified regression models to facilitate the interpretation of the results.
Results: The severity of depressive symptoms was correlated with the number of pain locations reported (Spearman's rho = .24, p < 0.001). We found a significant multiplicative interaction between depressive symptoms and musculoskeletal pain in predicting the risk of LTSA. Depressive symptoms and number of musculoskeletal pain locations were associated with increased risk of LTSA for individuals who did not have comorbid symptoms. However, we found no significant associations between the two predictors and LTSA among participants who reported comorbid symptoms.
Conclusions: The risk of LTSA associated with depressive symptoms and musculoskeletal pain appears to be moderated by the presence of comorbid symptoms. The modified risk for LTSA among workers with comorbid symptoms requires further investigation.

Source: Melkevik, O., Clausen, T., Pedersen, J., Garde, A. H., Holtermann, A. et Rugulies, R. (2018). BMC public health, 18(1).
https://doi.org/10.1186/s12889-018-5740-y

Overall risk index for patient transfers in total assistance mode executed by emergency medical technician-paramedics in real work situations

Few studies have quantified the risk of musculoskeletal disorders during patient transfers in total assistance mode in real-life prehospital emergency care situations. An index to assess the overall risk of patient transfers was created; it makes it possible to quantify risk based on the patient's position and the height of the patient's location. An analysis of 71 transfers executed by paramedics in actual work situations showed that moving a patient from the ground was characterized by acute sagittal flexions and axial rotations, respectively, 42% and 12% of the time. When the patient was lying on a raised surface, the lifting index and perceived exertion were the lowest (2.55; easy). According to the overall risk index, patient transfers from the ground are the riskiest. Paramedics execute many risky lifts even in favorable patient handling contexts.

Source: Larouche, D., Bellemare, M., Prairie, J., Hegg-Deloye, S. et Corbeil, P. (2019). Applied Ergonomics, 74, 177-185.
https://doi.org/10.1016/j.apergo.2018.08.029

A comparison of lumbar spine and muscle loading between male and female workers during box transfers

There is a clear relationship between lumbar spine loading and back musculoskeletal disorders in manual materials handling. The incidence of back disorders is greater in women than men, and for similar work demands females are functioning closer to their physiological limit. It is crucial to study loading on the spine musculoskeletal system with actual handlers, including females, to better understand the risk of back disorders. Extrapolation from biomechanical studies conducted on unexperienced subjects (mainly males) might not be applicable to actual female workers. For male workers, expertise changes the lumbar spine flexion, passive spine resistance, and active/passive muscle forces. However, experienced females select similar postures to those of novices when spine loading is critical. This study proposes that the techniques adopted by male experts, male novices, and females (with considerable experience but not categorized as experts) impact their lumbar spine musculoskeletal systems differently. Spinal loads, muscle forces, and passive resistance (muscle and ligamentous spine) were predicted by a multi-joint EMG-assisted optimization musculoskeletal model of the lumbar spine. Expert males flexed their lumbar spine less (avg. 21.9° vs 30.3-31.7°) and showed decreased passive internal moments (muscle avg. 8.9 % vs 15.9-16.0 %; spine avg. 4.7 % vs 7.1-7.8 %) and increased active internal moments (avg. 72.9 % vs 62.0-63.9 %), thus producing a different impact on their lumbar spine musculoskeletal systems. Experienced females sustained the highest relative spine loads (compression avg. 7.3 N/BW vs 6.2-6.4 N/BW; shear avg. 2.3 N/BW vs 1.7-1.8 N/BW) in addition to passive muscle and ligamentous spine resistance similar to novices. Combined with smaller body size, less strength, and the sequential lifting technique used by females, this could potentially mean greater risk of back injury. Workers should be trained early to limit excessive and repetitive stretching of their lumbar spine passive tissues.

Source: Gagnon, D., Plamondon, A. et Larivière, C. (2018). Journal of Biomechanics.
https://doi.org/10.1016/j.jbiomech.2018.09.017

Two-dimensional biomechanical thumb model for pipetting

Manual pipetting imposes repetitive movements, high force, and awkward postures on the thumb, fingers, and wrist, increasing the risk of musculoskeletal injuries. The purpose of this study is to provide a linear regression model to estimate the optimal pipetting grip height based on the two-dimensional biomechanical static thumb model developed in this study. This biomechanical static thumb model uses hand anatomy and static equilibrium conditions to estimate internal tendon forces against a given external force. Based on the model, we conclude that the optimal grip height is 3 cm in males and 2 cm in females in terms of grip strength and force efficiency. In addition, the model is validated by RMS EMG data from correlation analysis between the predicted internal tendon forces, with RMS EMG values of 0.65 for Flexor Pollicis Longus, 0.57 for Flexor Pollicis Brevis, and 0.61 for Adductor Pollicis.

Source: Kim, E. et Freivalds, A. (2018). International Journal of Industrial Ergonomics, 68, 165-175.
https://doi.org/10.1016/j.ergon.2018.07.008

An ergonomic field study to evaluate the effects of a rotatable handle piece on muscular stress and fatigue as well as subjective ratings of usability, wrist posture and precision during laparoscopic surgery

An explorative pilot study
Purpose: The interface between surgeon and the laparoscopic instrument is an important factor in biomechanical stress that may increase the risk of musculoskeletal complaints in surgeons. This article investigates the effect of a laparoscopic instrument with a rotatable handle piece (rot-HP) on muscular stress and fatigue during routine laparoscopic procedures (LP) as well as usability, wrist posture and working precision.
Methods: 40 LP (subtotal hysterectomies) performed by 11 surgeons were investigated. 20 LP were carried out with the rot-HP and 20 with a fixed (standard) laparoscopic handle piece instrument. Shoulder and arm muscle activity was monitored via surface electromyography (sEMG). The electrical activity (EA) and median power frequency (MPF) were used to determine muscular stress and fatigue. Usability, wrist posture, and working precision between handle piece conditions were assessed by a survey.
Results: Using the rot-HP did not reduce muscular stress. A tendency of muscular fatigue (increasing EA, decreasing MPF) occurred in the upper trapezius, middle deltoid and extensor digitorum muscles; however, no differences were found between handle pieces. Wrist posture was more comfortable using the rot-HP and working precision and usability tended to be preferred using the standard handle piece.
Conclusions: Although wrist posture seemed to be optimized by the rot-HP, no effect on muscular stress and fatigue was observed in routine LP (< 60 min duration). Optimization of wrist posture may provide positive effects in mid- or long-term procedures. However, sufficient familiarization with the new instrument is crucial since working precision and usability could be impaired.

Source: Kraemer, B., Seibt, R., Stoffels, A. K., Rothmund, R., Brucker, S. Y., Rieger, M. A. et Steinhilber, B. (2018). International archives of occupational and environmental health.
https://doi.org/10.1007/s00420-018-1344-1

The influence of external load configuration on trunk biomechanics and spinal loading during sudden loading

Sudden loading is a major risk factor for work-related lower back injuries among occupations involving manual material handling (MMH). The current study explored the effects of external weight configuration on trunk biomechanics and trunk rotational stiffness in the sagittal plane during sudden loading. Fifteen asymptomatic volunteers experienced sudden loadings using the same magnitude of weight (9 kg) with two different configurations (medially- or laterally-distributed) at three levels of height (low, middle and high). Results of this study showed that the medially distributed weight resulted in a significantly higher peak L5/S1 joint compression force (2861 N vs. 2694 N) and trunk rotational stiffness (2413 Nm/rad vs. 1785 Nm/rad) compared to the laterally distributed weight. It was concluded that when experiencing sudden loading, a more laterally distributed weight could increase the load's resistance to physical perturbations and alleviate spinal loading during sudden loading events.

Source: Madinei, S., Motabar, H. et Ning, X. (2018). Ergonomics.
https://doi.org/10.1080/00140139.2018.1489068

What do Workers do to Reduce Their Sitting Time?

The Relationships of Strategy use and Workplace Support with Desk-Based Workers' Behaviour Changes in a Workplace-Delivered Sitting-Reduction and Activity-Promoting Intervention
Objective: To explore workers' sitting-reduction and activity-promoting strategy use following an intervention targeting these changes, and whether strategy use and perceived workplace support impacted on three-month sitting and activity outcomes.
Methods: This secondary analysis in desk-based workers (n = 83) utilised data collected on questionnaire-derived strategy use and workplace support, and activPAL3TM-derived sitting (total; prolonged, ≥30mins) and activity (standing; stepping) at work.
Results: Fourteen strategies were commonly used during the intervention. Increased usage of some strategies were significantly (p < 0.05) associated with beneficial changes in prolonged sitting or stepping only. Workplace support was significantly beneficially associated with changes in sitting, prolonged sitting, and stepping; these associations were largely independent of strategy use changes.
Conclusions: Strategies were highly used, with increased use associated with some behavioural improvements. Workplace support appears essential for improving sitting and activity in the workplace.

Source: Brakenridge, C. L., Healy, G. N., Winkler, E. A. et Fjeldsoe, B. S. (2018). Journal of occupational and environmental medicine.
http://dx.doi.org/10.1097/JOM.0000000000001419

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