Ergonomics最新文献

Musculoskeletal disorders (MSDs) are prevalent under poor working situations. Where it is not possible to remove the root cause of MSDs, passive exoskeletons could be a solution. In this randomised cross-over field study we investigated the effect of a passive arm-support exoskeleton. Ten participants, recruited from a Dutch gas company, were measured with and without exoskeleton assessing muscle activity, heart rate (HR), arm elevation, and reported about their experiences. Participants spent more time in high arm elevation levels with the exoskeleton than without. Muscle activity was lower in the trapezius (Beta: -1.8 [-3.1; -0.4]) and deltoid (Beta: -1.4 [-2.3; -0.6]) muscles, but not the biceps muscle, during the measurements with exoskeleton than without, suggesting effectiveness of the exoskeleton. HR and discomfort did not statistically significantly differ between the two conditions. Participants would recommend an exoskeleton to their colleagues, but mainly for repetitive work. Their opinions about the usefulness during work varied.

To investigate the legibility of Chinese characters' font size, text background opacity, and font stroke for the elderly in virtual reality, we recruited old and young participants to conduct experiments with VR and used eye-tracking technology to record the data of task completion time and error rate. After analysis, we concluded that the minimum recognition font size for the elderly is 30 dmm, and the best font size is 60 dmm, which is 20 and 40 dmm for young people. The font style has a significant effect on old people (p = 0.000*). Besides, for font sizes smaller than 20 dmm and bigger than 50 dmm, text with strokes and over 50% semi-transparent backgrounds can improve legibility for the elderly. With a suitable font size, the influence of font style on the elderly is not significant. These conclusions can provide a reference for the elderly-oriented Chinese font design in VR.

This study proposes a generic approach for creating human factors-based assessment tools to enhance operational system quality by reducing errors. The approach was driven by experiences and lessons learned in creating the warehouse error prevention (WEP) tool and other system engineering tools. The generic approach consists of 1) identifying tool objectives, 2) identifying system failure modes, 3) specifying design-related quality risk factors for each failure mode, 4) designing the tool, 5) conducting user evaluations, and 6) validating the tool. The WEP tool exemplifies this approach and identifies human factors related to design flaws associated with quality risk factors in warehouse operations. The WEP tool can be used at the initial stage of design or later for process improvement and training. While this process can be adapted for various contexts, further study is necessary to support the teams in creating tools to identify design-related human factors contributing to quality issues.

This article brings together works on the concept of constructed safety in ergonomics, carried out over the last twenty-five years. Firstly, we situate this approach to safety in relation to previously developed existing models previously developed (e.g. regulated and managed safety) with regard to the development of activity-centred ergonomics. We then present six research actions in activity-centred ergonomics from a selection of different fields, from small companies to the industry of the future in an international group: public works, hospitals, aeronautical industry, railway transport, agriculture, and chemical industry, in order to describe constructed safety applications. The results highlight that constructed safety is respectively raised by mutual knowledge between workers and management, collective decision making, collective reflexive work on safety rules, spatiotemporal articulation of the different safety sources, knowledge integration on pesticide exposure situations by designers and regulation, social regulation sustaining risk understanding and safety aspect involving a diversity of actors (workers, preventionists, managers, local residents and public authorities). By focusing on the analysis of actual safety practices in real work and real exposure situations, constructed safety aims to account for the way in which safety is deployed on a daily basis to meet production and health objectives. This understanding contributes to the design of safe work systems in a developmental way and to propose an operating model of constructed safety.

Few studies investigate the impact of anterior-posterior excitation frequency on the time-domain vibrational response and injury risk of the lumbar spine in seated individuals. Firstly, this study utilised a previously developed finite element model of an upright seated human body on a rigid chair without a backrest to investigate the modes that affect the anterior-posterior vibrations of the seated body. Subsequently, transient dynamic analysis was employed to calculate the lumbar spine's time-domain responses (displacement, stress, and pressure) and risk factors under anteroposterior sinusoidal excitation at varying frequencies (1-8 Hz). Modal analysis suggested the frequencies significantly affecting the lumbar spine's vibration were notably at 4.7 Hz and 5.5 Hz. The transient analysis results and risk factor assessment indicated that the lumbar responses were most pronounced at 5 Hz. In addition, risk factor assessment showed that long-term exposure to 8 Hz vibration was associated with a greater risk of lumbar injury.

Load carriage is a key component of hiking and military activity. The design of the load carriage system (LCS) could influence performance and injury risk. This study aimed to compare a traditional and a compliant LCS during walking and a step-up task to quantify differences in oxygen consumption and trunk-pelvis kinematics. Fourteen participants completed the tasks whilst carrying 16 kg in a rigid and a compliant LCS. There were no differences in oxygen consumption between conditions during either task (p > 0.05). There was significantly greater trunk-pelvis axial rotation (p = 0.041) and lateral flexion (p = 0.001) range of motion when carrying the compliant LCS during walking, and significantly greater trunk-pelvis lateral flexion range of motion during the step-up task (p = 0.003). Carrying 16 kg in a compliant load carriage system results in greater lateral flexion range of motion than a traditional, rigid system, without influencing oxygen uptake.

A prospective, qualitative study, of trauma and orthopaedic theatres was undertaken using the CARe QI handbook and the SEIPS framework, with the aim of preventing future Never Events. The study demonstrated a new approach, focussed on understanding 'work as done' to identify opportunities to improve system resilience, tested, using the Model for Improvement. Undertaken during the Covid-19 pandemic, it demonstrates that such conditions should not be a deterrent to observational studies, but requiring greater time and resource than a standard investigation, the approach may not align with current organisational or regulatory expectations. At the conclusion of this study, the mean time between Never Events in theatres had increased from 46 to 224 days, an achievement that had not previously been possible using the regulatory required, safety I, investigatory approach. These findings should be used to inform future PSIRF and Never Event Frameworks, to ensure effective systems-based analysis and improvement.

This study investigates driving behaviour in different stages of rear-end conflicts using vehicle trajectory data. Three conflict stages (pre-, in-, and post-conflict) are defined based on time-to-collision (TTC) indicator. Four indexes are selected to capture within-group and between-group characteristics of the stages. Besides, this study also examines the prediction performance of conflict stage identification using specific driving behaviour characteristics associated with each stage. Results reveal variations in dominant driving characteristics and predictive importance across stages. Heterogeneity exists within stages, with differences among clusters. Drivers slow down during in-conflict, with decreasing speed reduction as stages progress. Reaction time increases in post-conflict. Insufficient space gaps contribute to rear-end conflicts in the in-conflict stage. Furthermore, the prediction performance of conflict stage identification, based on the specific driving behaviour characteristics associated with each stage, is commendable. This study enhances understanding and prediction of conflict stage identification in rear-end conflicts.Practitioner summary: This study explores driving behaviour in rear-end conflict stages using trajectory data. It identifies pre-, in-, and post-conflict stages via time-to-collision indicator and assesses within-group and between-group characteristics. Besides, prediction performance for conflict stage identification based on these characteristics is commendable. This research enhances understanding and prediction of rear-end conflicts.

Identifying contacts in a military context can require operators to integrate multiple cues and to adjust response criteria to event base rates. The current experiment tested whether support from a decision aid would improve these processes. Participants performed a signal identification task that required them to integrate cues displayed as visual scale readings. In a static condition, participants saw a single set of readings each trial. In dynamic conditions, readings were updated over time. Base rates of signal categories were unequal, requiring participants to adopt biased response criteria to maximise response accuracy. Participants worked with or without an aid that combined cues and base rate information in an ideal manner. Support from the aid pushed participants' response criteria towards optimal and improved integration of dynamic cues. Decision aids may be especially useful when task demands require biased response criteria and when cues are sampled over time.

Selling products in kit form to consumers benefits both manufacturers and consumers - provided the instructions enable the customer to assemble the components correctly and safely. Poor usability of some self-assembly instructions is a continuing cause of consumer complaints- but the subject of only occasional ergonomics research interest. Relevant studies are widely dispersed across the literature - and across decades - but their findings generally agree on what makes some self-assembly illustrations more effective than others. This has just not been consolidated in any formally recognised guidance. This study has produced a comprehensive review of published work on the usability of self-assembly instructions (which need to convey most information pictorially) and makes detailed recommendations for best practice in their presentation. The evidence for the recommended best practices discussed in this paper will be reflected in the publication of an international standard that which is currently in the final drafting stages.