Influence of anterior load carriage on lumbar muscle activation while walking in stable and unstable shoes

Load carriage can be harmful for workers, and alternative interventions to reduce back pain while walking and carrying loads are necessary. Unstable shoes have been used to improve balance and reduce back pain, but it is unknown whether walking wearing unstable shoes while carrying loads anteriorly causes excessive trunk extensors muscle activation. The aim of this study was to investigate the effects of different shoe types and anterior load carriage on gait kinematics and lumbar electromyographic (EMG) activity. Fourteen adults that predominantly walk or stand during the work day were asked to walk with and without carrying 10% of body mass anteriorly while wearing regular walking shoes (REG) and unstable shoes (MBT). The effects of shoe type, load carriage, and shoe × load interactions on the longissimus thoracis (LT) and iliocostalis lumborum (IC) EMG, stride duration, and stride frequency were assessed. MBT shoes induced a significant increase in LT (44.4 ± 35%) and IC EMG (33.0 ± 32%, p < .005), while load carriage increased LT (58.5 ± 41%) and IC EMG (55.1 ± 32%, p < .001). No significant shoe × load interaction was found (p>.05). However, walking wearing MBT shoes while carrying loads induced a 46 ± 40% higher EMG activity compared to walking wearing MBT shoes without load carriage. No effects of shoes or load carriage were found on stride duration and stride frequency. It was concluded that walking wearing MBT shoes and carrying 10% of total body mass induced greater activation of trunk extensors muscle compared to these factors in isolation, such a combination may not influence gait patterns.     

The epistemic implications of engineering rhetoric

The texts (and talk) of engineers take different forms. In this essay, I present and critique several texts written for different purposes and audiences but all intended to convey to the reader the technical details of whatever they are about—whether a textbook passage describing the fundamental behavior of an electrical component, a journal article about a mathematical technique intended for use in design optimization, a memo to co-workers within a firm about a heat transfer analysis of a remotely sited building, or a general introduction to the field of? ergonomics? My aim is to explore how the ways in which engineers describe and document their problems and projects frame what they accept, display and profess as useful knowledge. In this I am particularly interested in how engineers envision the ‘users’ of, or participants in, their productions. Like science, engineering texts are written as if they were timeless and untainted by socio-cultural features. However, a technical treatise is not devoid of metaphor or creative rendering of events; there is always a narrative within which worldly data and instrumental logic is embedded—but it is a story in which the passive voice prevails, history is irrelevant, and the human actor or agent is painted in quantitative parameters fitting the occasion. Whether this rhetoric can be sustained in the face of challenges to traditional ways of doing engineering is an open question.     

Les pratiques professionnelles au cœur de la crise dans la gestion de l’urgent : l’exemple de la crise du COVID-19

Our organisations have been severely shaken by the COVID-19 pandemic and the world of work has not been spared. Only essential activities continued in order to maintain a minimum level of functioning, just like in hospitals or in local authorities. During the first five months of the crisis in 2020 (from March to July), 34 interviews were conducted in these two public service entities in order to examine the management of urgent matters in the light of “activity” and at the heart of the crisis. The results show that while the emergency is mainly managed by an improvisation activity based on the intuition of the actors in the field, the crisis is managed by governance in a rational manner leading to the drafting of procedures after the event. This crisis situation pushed organisations to reconfigure themselves in an emergency, allowing the development of new professional practices. The strategies of damage control and proceduralization will be discussed. Perspectives are opened on the questions of training for these crisis situations against a background of developing presumption of ignorance.     

Walking breaks can reduce prolonged standing induced low back pain

Standing is commonly recommended to reduce sedentary behavior in the workplace; however, constrained prolonged standing has also been linked to musculoskeletal symptoms, such as low back pain (LBP). Light physical activity breaks, such as walking, may change lumbar spine posture enough to reduce LBP during standing. This study assessed the effectiveness of inserting 5-minute walking breaks every 25 min for reducing prolonged standing-induced LBP development. Nineteen participants completed two bouts of standing lasting 2 h – one with a 5-minute walking break every 25 min and one with no breaks. Pain measures were completed throughout the trial to categorize participants as pain developers (PDs) or non-pain developers (non-PDs). Lumbar region kinematics angle and range of motion were measured continuously. In standing, 58% (11/19) of participants were PDs, compared to just 26% when walking breaks were inserted. Seventy-three percent (8/11) were categorized as non-PDs with walking breaks. Median lumbar flexion increased during walking compared to standing. Lumbar region range of motion in the coronal and transverse planes also increased during walking. The intermittent lumbar flexion may help decrease LBP during prolonged standing. These results demonstrate that walking breaks may help promote lumbar movement and reduce prolonged standing-induced LBP.     

Neck posture is influenced by anticipation of stepping

BackgroundPostural deviations such as forward head posture (FHP) are associated with adverse health effects. The causes of these deviations are poorly understood. We hypothesized that anticipating target-directed movement could cause the head to get “ahead of” the body, interfering with optimal head/neck posture, and that the effect may be exacerbated by task difficulty and/or poor inhibitory control.MethodWe assessed posture in 45 healthy young adults standing quietly and when they anticipated walking to place a tray: in a simple condition and in conditions requiring that they bend low or balance an object on the tray. We defined FHP as neck angle relative to torso; we also measured head angle relative to neck and total neck length. We assessed inhibitory control using a Go/No-Go task, Stroop task, and Mindful Attention Awareness Scale (MAAS).ResultsFHP increased when participants anticipated movement, particularly for more difficult movements. Worse Stroop performance and lower MAAS scores correlated with higher FHP. False alarms on the Go/No-Go task correlated with a more extended head relative to the neck and with shortening of the neck when anticipating movement.ConclusionsMaintaining neutral posture may require inhibition of an impulse to put the head forward of the body when anticipating target-directed movement.     

Group cycling safety behaviours: A systematic review

BackgroundThe popularity of cycling in a group is longstanding and increasing. Compared to riding as an individual, many cyclists feel safer when riding in a group as they have better personal security, potential support in case of mishaps, safer wayfinding and are more visible to other road users. However, further to the safety challenges shared with individual cyclists, group cyclist safety is impacted by rider proximity, the larger space taken up on roadways, potentially higher speeds, and social norms that could increase risky behaviours. Despite these unique safety considerations, the practice of cycling in groups has received little academic attention and group cyclist safety behaviours have not been analysed by road safety researchers.ObjectiveTo identify, describe, categorise and conceptualise within a teamwork framework, safety related behaviours of groups of cyclists as mentioned in academic literature.MethodsThree academic databases (Google Scholar, Proquest, and Scopus) were searched for peer reviewed literature that mentioned safe or risky behaviours of groups of cyclists. A total of 32 papers met the inclusion criteria. Relevant group cyclist behaviours were described and categorised using a conceptual teamwork framework.ResultsGroup cyclists’ safety behaviours are governed by a comprehensive but informal and adaptable set of rules. These rules are safety critical and are often strictly controlled within groups. Many groups of cyclists may ride in a safer manner than individual cyclists due to teamwork factors, particularly shared mental models, team orientation, and adaptability.ConclusionGroup cyclists take safety seriously. Teamwork factors may make behavioural interventions to decrease risky behaviours easier to implement with group cyclists compared to individual cyclists. Investigation of group cycling safety behaviours may inform safe system interventions to increase road safety.     

学习论视角下的教育工效学理论模型的发展与应用

教育工效学是工效学研究中长期被忽视的重要研究领域,其发展以各教育工效学模型的提出为主线。本文从模型设计、模型应用和学习论视角出发,分析了Kao模型,Smith模型和六角轴模型的理论基础,发现现有的这三个模型在设计上多从工效学角度出发,与学习论的结合不够紧密。为了给信息化教学系统设计提供更有价值的理论模型和更可行的设计方法,有必要从工效学原理与教学理论的深度衔接入手,并基于学习论的视角给模型应用和完善提供一些可行的建议。     

Ergonomie cognitive d’un conseil génétique pour le test présymptomatique de maladie de Huntington

We would like to propose the analysis of a multidisciplinary genetic counselling activity. More precisely, we study an interaction that took place in the consultation between an asymptomatic patient who requests for a predictive genetic testing of Huntington’s disease and two doctors successively. We describe the failure of the multidisciplinary team’s attempt to influence the conviction, or the personal rationality, of the patient for the genetic risk perception. More generally, this study illustrates the communication practices which are engendered by modern medicine can be very delicate. Therefore, this information is carried by the act of informing. This action is made of processes which are relatively independent.     

Développement des collectifs de travail et développement de la sécurité : une étude sur les décisions à risque en anesthésie

This article highlights the collective dimensions of risk management for patients before an anesthesia. After a phase of observation of real activity, interviews were conducted with 20 anesthetists from two French hospitals. The analysis reveals interindividual diversity in practices. This diversity is explained by the inclusion, in decisions, of knowledge about “distributed” skills in the team and about local “shared practice”. The results establish a link between the site where the anesthetists are working and the choice of an anesthetic technique. They also show that the positioning of anesthetist vis-à-vis the “shared practice” is significantly related to their seniority in the profession. These results open perspectives for research and intervention for the joint development of collective work and safety.     

“They would call me,and I would need to know because it is like life and death”: A qualitative examination of the acceptability of smartphone applications designed to reduce mobile phone use while driving

Distracted driving is one of the most prevalent risky behaviours worldwide. Research has highlighted that current approaches to distracted driving based on education and police enforcement have shown low effectiveness. Smartphone applications to reduce distracted driving are an emerging technology with the potential to prevent road crashes. However, recent evidence has shown that the adoption of these applications has been limited. A qualitative study was carried out to investigate the acceptability of smartphone applications that are designed to prevent distracted driving. A total of 35 drivers (57% females) aged 19–44 years (Mean = 28.43) participated in interviews which explored acceptability constructs for in-vehicle intelligent technology as defined by Regan et al. (2012): usefulness, usability, effectiveness, social acceptability, affordability, and willingness to use the application functions. Generally, drivers perceived that these applications have the potential to increase safety and reduce voluntary and involuntary mobile phone interactions while driving. Nonetheless, it was also found that drivers want to retain some of the functionalities of their mobile phone, such as music playing applications, accessing GPS/maps and being able to interact with certain groups of people through their phones while driving. Finally, barriers to the uptake of the applications among drivers who use their mobile phone while driving are discussed. A frequent barrier that needs to be overcome is the perceived need and pressure to respond to their phone while driving to communicate for work purposes or with people with strong social ties to the driver, for example, a parent or spouse.