Characteristics of Muscular Load in Computer Data Entry Workers Assessed by EMG and Postural Angles

The goal of this study was to characterize the muscular load in computer data entry workers. Electromyography (EMG) parameters of trapezius muscle and postural angles of head, arm, and back were chosen as indicators of musculoskeletal load. The examination was done according to the methods and protocol of international MEPS studies (the “Musculoskeletal, Visual, and Psychosocial Load in VDT [Video Display Terminal] Operators in Optimized Environment” international program). The musculoskeletal load during routine VDT data entry work performed by a group of 36 women was assessed on the basis of 1-hr physiometer recordings. Results show that the musculoskeletal load associated with data entry is relatively high compared to other VDT operators’ tasks described in the literature. An analysis of the measured parameters shows that most of the time women worked with a muscular load higher than optimal. It is postulated that the main reason for the heavy musculoskeletal load was improper posture compelled by unergonomic spatial configuration of work stands.     

合理构建视频显示终端(VDT)作业疲劳工间休息制度

为了减少VDT(视频显示终端)作业对操作者健康的负面影响,合理地安排工作和休息时间以及设计良好的工作环境有助于减轻、缓解或消除VDT作业的疲劳。通过多项VDT数据输入作业实验,依据作业者作业能力变动的规律性,对不同类型的VDT作业者可能需要设置不同的工间休息制度。经过对实验数据的分析,数据输入的工作主要是信息接受和信息输出,属于事务性脑力劳动。只要合理地安排工作和休息时间以及设计良好的工作环境,就可以减少VDT对眼睛、骨骼及肌肉的疾患发生。     

Perceived Discomfort and Electromyographic Activity of the Upper Trapezius While Working at a VDT Station

Ten female participants performed work at a video display terminal (VDT) station over a whole working day. Subjective local muscular fatigue was evaluated by means of the Category Ratio 10 scale. Electromyographic activity of the upper right and left trapezius was measured. A comparison was made between 5 participants who had previous complaints and 5 participants who reported no musculoskeletal problems in the shoulder-neck region. The subjective scores for the shoulder differed significantly between the two groups, being higher for the group with complaints. Both groups showed a decrease in discomfort after the lunch break. The activity of the trapezius increased significantly for both groups, in a more pronounced way for the group with disorders. Although it is found in literature that VDT work is a task with very low static loads, it seems from this study that the EMG activity increase can be an indication of muscle fatigue: More effort was required to accomplish the same VDT task at the end of the day.     

Implementation of ophthalmological tests in periodic eye checkups for VDT workers in Japan

The National Federation of Industrial Health Organizations has offered training courses for medical staff belonging to Occupational Health Organizations to overcome the difficulty of carrying out periodic eye-checkups for VDT workers in Japan since 1991. Through detailed evaluation by participants, the course contents have been improved. Today the participants in the courses number 643, thus contributing to the improved medical examinations for VDT operators.     

基于心理资本的机场安检员工作不安全感对工作绩效的影响

为研究机场安检员不安全感对工作绩效的影响,基于心理资本调节作用提出工作不安全感对工作绩效(任务绩效、周边绩效、适应绩效)影响研究假设,以机场安检员为研究样本进行纵向实证研究,运用多元层次回归分析法探究工作不安全感与3种工作绩效的作用路径及心理资本的调节效应。结果表明:工作不安全感与任务绩效、周边绩效、适应绩效3种工作绩效指标间存在纵向U形曲线关系,并且这种U形关系只存在于心理资本较低的机场安检员;心理资本在工作不安全感与工作绩效之间起调节作用;可开发的心理资本能够削弱机场安检员工作不安全感与工作绩效间的纵向曲线效应。研究结论可为改善机场安检员工作绩效管理模式、提升民航业安检运行水平提供参考。     

基于模糊评价的VDT系统搜索策略绩效形成机理研究

为优化视觉显示终端（VDT）结构性搜索界面的布局,提高作业绩效和安全,设计了VDT系统搜索实验,构建了搜索目标位置在4个主观偏好指标下的Pythagorean模糊集决策矩阵,运用交互式多准则决策（TODIM）法计算各目标位置偏好的总体优势度并排序;同时对VDT系统搜索实验中各目标位置的绩效进行方差分析并排序,分析系统搜索策略下作业者对目标位置的主观偏好与绩效之间的关系。研究结果表明:基于系统搜索策略的VDT作业绩效在不同目标位置差异显著;导致绩效差异的根本原因是作业者对搜索目标位置的主观偏好度,而不是搜索目标的位置属性;除中心区域外,偏好度高的区域搜索绩效要优于偏好度低的区域。     

视屏显示终端对精神心理和神经行为的影响

本文进行了视屏显示终端(VDT)对操作人员精神心理和神经行为影响的调查研究。初步显示VDT作业可对操作人员造成情绪、感知、记忆、操作及复合功能诸多方面的不良影响。通过职业应激源的调查评价,显示VDT作业本身独特的作业性质、环境和要求形成了VDT作业的主要应激源。对从事VDT作业时间较长和作业负荷较大者则产生较高的职业性紧张度。从而说明VDT作业引起操作人员的某些心身疾患的可能性。     

Morphology-Related Isometric Trunk Strength of South African Manual Workers: Implications for Prevention of Occupational Low-Back Stress

Occupational back stress among manual workers in South Africa is now a cause of governmental concern. Yet no data on the back strength of the South African workforce have been published. This study represents a first step in reporting the trunk strength of Xhosa workers in South Africa, in absolute and size-relative terms. Thirty-five male manual workers were tested isometrically while making maximal extension and flexion efforts at 0°, 23°, 46°, 69°, and 92° of stoop. The results show nonlinearity of the extensor-to-flexor (E/F) ratio of the trunk musculature. The E/F ratio increases in deep stoop because of a drop in flexor torques. The data suggest that predictions of flexor from extensor torques or vice versa can confidently be made so long as testing is done away from the fully flexed position. Significant differences between morphologically gracile and robust workers in this sample are discussed. The study has implications for occupational rehabilitation and for prophylaxis, for whereas muscular strength alone may not protect the spine from occupational injury, muscular weakness certainly predisposes it.     

时间压力视角下人格特征与VDT视觉搜索绩效的关系及形成机理*

为合理选拔和培训特定情境下的视觉搜索安检人员,从时间压力视角分析大五人格特征与视觉显示终端（visual display terminal,VDT）的视觉搜索绩效的关系。通过变量分析和设计,提出VDT视觉搜索绩效影响因素理论模型;运用Visual Studio设计实验模拟视觉搜索安检任务,采集绩效及眼动数据;最后进行有中介的调节模型检验。研究结果表明:不同人格特征的VDT视觉搜索绩效存在差异;所有人格特征的搜索策略随机指数随时间压力的增加而降低,但调整强度在不同人格特征之间存在差异,严谨性人格调整幅度最大;时间压力通过搜索策略的中介作用（部分）间接调节人格特征与VDT视觉搜索绩效的关系;较高和较低时间压力下,严谨性人格通过有效的搜索策略调整,绩效最好;中等时间压力下,开放性人格的绩效最好。研究结果可为视觉搜索作业人员的选拔和培训提供理论依据。     

建筑基坑施工习惯性不安全行为干预研究

事故致因"2-4模型"提出习惯性行为是引发事故的间接原因,为了提高基坑作业人员安全知识、安全意识和安全习惯,防止基坑坍塌事故对工程施工造成的人员伤亡和财产损失,以西安某地铁施工现场为调查对象,同时根据跨理论模型(TTM)的行为干预方法,设立对照组和实验组,使用SPSS软件分析对调查对象进行对比分析.研究表明:基于TTM...     

防护服对消防员工效性能影响的定量研究*

为开发高性能防护服以提升救援效率,基于人体试验,测量受试者穿戴灭火防护服、半封闭防化服、全封闭防化服以及基础服装（对照组）时静态条件下左右手握力值、疲劳度（RPE）和活动受限程度,通过方差分析、接受者操作特征（ROC）曲线图、相关性分析进行定量研究。研究结果表明:灭火防护服对消防员工效性能影响大于防化服,灭火防护服较对照组握力减小32%、RPE增大54%、活动受限程度增大35倍,且RPE和活动受限程度均与握力呈显著负相关（p<0.001）。研究结果可为消防员个体防护服装设计、测试、性能提升等提供理论支撑,也可为消防员生命安全保障研究提供基础数据。     

Risk Assessment in the Working Environment in Estonia

The first step to chart hazards in the working environment in Estonia (labour force: 0.65 million) was taken by the National Board of Health Protection in the beginning of 1996.

The existing chemical, physical, and biological agents in the working environment were investigated with the help of local health inspectors in all counties. An identification of hazards and workers at risk was carried out. The results of the analysis showed that 16% of Estonian industrial workers are exposed to different hazards: 20,000 persons are exposed to noise, 11,000 are working in the conditions of vibration, 10,000 are affected by unsatisfactory microclimate, 6,000 complain about long-lasting work in a compulsory posture, the overexertion of eyes is suffered by 5,500 persons, and physical overload by 3,500 workers. In the group of chemical hazards the greatest numbers of workers are exposed to organic dust (6,500) and welding aerosols (5,400), followed by petroleum products (2,700), and oil-shale dust (4,300). The measurements of working conditions showed that an average of 30.3% of the results are above the standards. Proposals for the improvement of the situation in occupational safety and health are presented.     

Postural and Muscular Responses While Viewing Different Heights of Screen

This study aimed to examine the effects of visual display terminal (VDT) viewing angle on human postural angle and muscular activity. The participants’ neck, thoracic bending, and trunk inclination angles; and the activity of sternocleidomastoid, trapezius, splenius capitis, and erector spinae at 5 viewing angles (+40°, +20°,0°, –20°, and –40°) of a VDT screen were collected for 1 min. This study showed that neck and thoracic bending angles increased with viewing angle, while viewing angle did not significantly affect trunk inclination angle. In addition, the activity of trapezius and erector spinae increased when viewing a higher or lower VDT screen height compared with viewing a horizontal VDT screen height; however, the activity of splenius capitis decreased with viewing angle.     

Luminance of the Surround and Visual Fatigue of VDT Operators

Luminance distribution in the visual field is considered as one of causal factors with a significant influence on visual fatigue, especially for intensive and extended Video Display Terminal (VDT) work. The aim of the study was to define visual fatigue of VDT operators for different values of surrounding luminance. Experiments were carried out in laboratory conditions under 3 lighting conditions. Only 1 lighting parameter—the luminance of the wall behind the display (surrounding luminance)—changed. Visual fatigue was measured both by a subjective evaluation of different visual complaints (asthenopic symptoms) and by objective measurements of changes in the following visual functions: accommodation, convergence, habitual horizontal phoria, critical fusional frequency (CFF), and visual acuity. The same experiments were done for CRT (Cathode Ray Tube) and LCD TFT (Liquid Crystal Display with Thin Film Transistor) screens. The results of the study have shown that there was no significant influence of the value of surrounding luminance on the asthenopic symptoms for either type of screen. A general tendency towards bigger visual complaints for LCD TFT than for CRT participants was found. An objective evaluation of visual fatigue demonstrated a tendency towards bigger changes in visual functions with an increase of surrounding luminance for both screens. Statistical analysis of the results has shown that surrounding luminance influences significantly the reduction of the accommodation amplitude (significance level < .05).     

Development of prolonged standing strain index to quantify risk levels of standing jobs

Many occupations in industry such as metal stamping workers, electronics parts assembly operators, automotive industry welders, and lathe operators require working in a standing posture for a long time. Prolonged standing can contribute to discomfort and muscle fatigue particularly in the back and legs. This study developed the prolonged standing strain index (PSSI) to quantify the risk levels caused by standing jobs, and proposed recommendations to minimize the risk levels. Risk factors associated with standing jobs, such as working posture, muscles activity, standing duration, holding time, whole-body vibration, and indoor air quality, were the basis for developing the PSSI. All risk factors were assigned multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness. multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness.     

Evaluation of pliers’ grip spans in the maximum gripping task and sub-maximum cutting task

A total of 25 males participated to investigate the effects of the grip spans of pliers on the total grip force, individual finger forces and muscle activities in the maximum gripping task and wire-cutting tasks. In the maximum gripping task, results showed that the 50-mm grip span had significantly higher total grip strength than the other grip spans. In the cutting task, the 50-mm grip span also showed significantly higher grip strength than the 65-mm and 80-mm grip spans, whereas the muscle activities showed a higher value at 80-mm grip span. The ratios of cutting force to maximum grip strength were also investigated. Ratios of 30.3%, 31.3% and 41.3% were obtained by grip spans of 50-mm, 65-mm, and 80-mm, respectively. Thus, the 50-mm grip span for pliers might be recommended to provide maximum exertion in gripping tasks, as well as lower maximum-cutting force ratios in the cutting tasks.     

Work environment and the well-being of clerical and VDT workers

This paper explores the relationships between extent of video display terminal usage, perceptions of the physical work environment, task characteristics, and workers' health and well-being among a group of 1032 female office clerical workers. Data are drawn from responses to a 30-minute questionnaire administered at four employment sites during 1981 and 1982. All-day terminal users reported significantly higher levels of job and physical environment stressors than part-day VDT users, typists and non machine-interactive clerical workers. Reports of musculo-skeletal strain and dissatisfaction were also highest among all day terminal users. Part-day VDT users, typists and clerks all reported relatively similar levels of job and physical working conditions, health symptoms and job satisfaction. No significant differences between any of the groups were observed for gastrointestinal, respiratory, psychological and other non-specific health complaints. Typists and clerical workers who also held supervisory positions reported fewer stressors and greater job satisfaction than workers with no supervisory tasks; however there were no such differences between supervisors and non-supervisors engaged in all-day VDT work. Implications of these findings for further research and for job redesign strategies to alleviate the potentially stressful aspects of office automation are discussed.     

Worker safety and injury severity analysis of earthmoving equipment accidents

Introduction: Research on construction worker safety associated with construction equipment has mostly focused on accident type rather than injury severity and the embedded factor relationships. Significant variables and their effects on the degree of injury are examined for earthmoving equipment using data from OSHA. Four types of equipment, backhoe, bulldozer, excavator, and scraper are included in the study. Accidents involving on-foot workers and equipment operators are investigated collectively, as well as separately. Methods: Cross tabulation analysis was conducted to establish the associations between selected categorical variables, using degree of injury as a dichotomous dependent variable (fatal vs. nonfatal) and a number of independent variables having different values. Odds ratios were calculated to determine how much a certain variable/factor increases the odds of fatality in an accident, and the odds ratios were ranked to determine the relative impact of a given factor. Results: It was found that twelve variables were significantly associated with injury severity. Rankings based on odds ratios showed that inadequate safety training (2.54), missing equipment protective system (2.38), being a non-union worker (2.26), being an equipment operator (1.93), and being on or around inadequately maintained equipment (1.58) produced higher odds for fatality. Conclusion: A majority of the earthmoving equipment accidents resulted in fatality. Backhoes were the most common equipment involved in accidents and fatalities. Struck-by accidents were the most prevalent and most fatal. Non-OSHA compliant safety training, missing seatbelt, operator not using seatbelt, malfunctioning back-up alarms, and poorly maintained equipment were factors contributing to accidents and fatalities. On-foot workers experienced a higher number of accidents than operators, while fatality odds were higher for the operators. Practical applications: Safety professionals should benefit from our findings in planning and delivering training and providing oversight to workers in earthmoving equipment operations.     

园林工人割灌作业职业性肌肉骨骼疾患的工效学研究

职业性肌肉骨骼疾患是园林工人的常见职业病,严重影响园林工人的工作效率和身体健康。对18名从事园林割灌作业的工人通过NMQ北欧肌肉骨骼系统问卷调查表进行调查,统计得出园林割灌作业的下背痛患病率约在60%左右,从事割灌整枝作业工人下背痛患病率为25%,从事割草作业下背痛患病率达444%,割草作业的下背痛患病率明显高于割灌整枝操作者。应用SPSS190软件进行下背痛的危害因子分析,得出下背痛的发生主要与重复动作、工龄、日提举负荷等有关。     

Impact of posture and upper-limb muscle activity on grip strength

Purpose. The current research was carried out to determine grip strength (GS) with change in posture and upper-limb muscle activity of manual workers and investigate the impacts of these changes. Methods. For the current research, 120 male and 80 female participants were selected and GS was assessed using a digital hand grip dynamometer in various conditions. Results. The outcomes showed that male participants had higher GS as compared to female participants. Maximum GS was found in a standing posture with the fixed forward shoulder at 45°, elbow at 90° and a neutral position of the wrist and forearm for all participants. Conclusions. Higher values of GS were attained in standing postures which may result in attainment of higher performance levels by the workers. The outcomes justify the importance of correct postures during manual work in industries employing traditional methods.