Clare Pollock

THE INFLUENCE OF SUSTAINED ATTENTION ON RAILWAY ACCIDENTS

Train accidents and near accidents occurring over a 3-year period were examined within an Australian public rail authority. Retrospective analysis of 112 incidents according to Reasons (1992) Generic Error Modelling System (Reason, 1992, Human Error. Cambridge University Press, Cambridge), revealed a propensity of skill based errors across the more common types of rail mishaps. In agreement with previous rail research, sustained attention was the most salient contributing human factor across all incident types, particularly inattentiveness to railway signals. The unfavourable nature of the working environment and the repetitive nature of the train driving task are discussed in light of reducing attentional deficits. In addition, a Railway Safety Checklist was developed to identify train drivers perception of safety. One hundred and ninety train drivers indicated that staff attitude in the form of low morale was a serious problem in the safe conduct of their job. The results of this study imply that useful strategies for improving driver vigilance should be directed at improving the safety culture of the operating environment.

A comparison of posture and muscle activity during tablet computer, desktop computer and paper use by young children

Computers are now widely used by children. Tablet computers are becoming widely available and promoted for use by school children. The primary objective of this study was to compare the posture and muscle activity of children using a tablet computer to the posture and muscle activity of children using a desktop computer and paper technology. Eighteen children (mean age 5.6 years) performed a colouring-in task in tablet, desktop and paper conditions. 3-D posture and muscle activity around the neck and shoulder was assessed. Tablet computer use was similar to paper use, with less neutral spinal posture, more elevated scapular posture and greater upper trapezius and cervical erector spinae activity. This was offset by greater variability of posture and muscle activity. Tablet computer use clearly results in different musculoskeletal stresses than desktop computer use. Computer use guidelines need to be appropriate to traditional and emerging technologies. Tablet computers are being promoted for use by adults and children. However, the physical impact of using this type of technology is not known. The findings of this study provide the first tablet-specific evidence to inform guidelines on wise use of tablet computers by children.

Principles for the wise use of computers by children

Computer use by children at home and school is now common in many countries. Child computer exposure varies with the type of computer technology available and the childs age, gender and social group. This paper reviews the current exposure data and the evidence for positive and negative effects of computer use by children. Potential positive effects of computer use by children include enhanced cognitive development and school achievement, reduced barriers to social interaction, enhanced fine motor skills and visual processing and effective rehabilitation. Potential negative effects include threats to child safety, inappropriate content, exposure to violence, bullying, Internet ‘addiction’, displacement of moderate/vigorous physical activity, exposure to junk food advertising, sleep displacement, vision problems and musculoskeletal problems. The case for child specific evidence-based guidelines for wise use of computers is presented based on children using computers differently to adults, being physically, cognitively and socially different to adults, being in a state of change and development and the potential to impact on later adult risk. Progress towards child-specific guidelines is reported. Finally, a set of guideline principles is presented as the basis for more detailed guidelines on the physical, cognitive and social impact of computer use by children. The principles cover computer literacy, technology safety, child safety and privacy and appropriate social, cognitive and physical development. The majority of children in affluent communities now have substantial exposure to computers. This is likely to have significant effects on child physical, cognitive and social development. Ergonomics can provide and promote guidelines for wise use of computers by children and by doing so promote the positive effects and reduce the negative effects of computer–child, and subsequent computer–adult, interaction.

A randomized and controlled trial of a participative ergonomics intervention to reduce injuries associated with manual tasks: physical risk and legislative compliance

A participative ergonomics approach to reducing injuries associated with manual tasks is widely promoted; however only limited evidence from uncontrolled trials has been available to support the efficacy of such an approach. This paper reports on a randomized and controlled trial of PErforM, a participative ergonomics intervention designed to reduce the risks of injury associated with manual tasks. One hundred and seventeen small to medium sized food, construction, and health workplaces were audited by government inspectors using a manual tasks risk assessment tool (ManTRA). Forty-eight volunteer workplaces were then randomly assigned to Experimental and Control groups with the Experimental group receiving the PErforM program. Inspectors audited the workplaces again, 9 months following the intervention. The results showed a significant decrease in estimates of manual task risk and suggested better legal compliance in the Experimental group.

The effect of shoulder posture on performance, discomfort and muscle fatigue whilst working on a visual display unit

Abstract An investigation was conducted to determine the relationship between posture and performance while working on a VDU. Twenty-one female subjects performed a 20 min choice reaction time task in a within-subject design with shoulder flexion (0° versus 30°) and noise (55 dB versus 75 dB) as factors. Discomfort measures, electromyography (EMG) measures and measures of performance including reaction time and percentage of errors were collected. The results suggested poorer performance in the 30° shoulder flexion posture compared to the 0° shoulder flexion posture (performance index F 1,20 = 3.95, p = 0.061). There was also significantly greater discomfort and fatigue, as indicated by EMG, in the 30° shoulder flexion compared to 0° shoulder flexion (discomfort: F 1,20 = 99.30; p = 0.0001 EMG: F 1,20 = 4.25, p = 0.052). The results of this study provide the most direct evidence that the posture of VDU users can affect their performance at a task. A number of possible mechanisms for posture to affect performance are explored using the data. The utility of data showing the effect of posture on performance data is discussed in terms of financial modelling to justify the cost of ergonomic intervention. Relevance to industry Poor posture whilst working at a VDU has been previously linked with the development of poor health but has not been directly linked with poor performance. This paper provides evidence to show posture can effect VDU performance. This enables organisations to use estimates of performance changes to model the costs of investment in ergonomic interventions.

Optimizing the interaction of children with information and communication technologies

This paper outlines the major changes in the lives of children in industrially advanced countries associated with the increased interaction with information and communication technologies. The potential opportunities and threats to the cognitive, social, physical and visual development of children are reviewed to emphasize the importance of optimizing the interaction. The change in childrens use of technology also poses opportunities and threats for ergonomics that should be noted if the profession is to continue being relevant and useful into this century. The paper ends with a pathway to the development and implementation of guidelines about child information and communication technology use for different groups of guideline users.

A case study of the use of ergonomics information in a heavy engineering design process

Abstract The aim of this case study was to investigate the use of ergonomics information in an engineering design companys design process. Interviews were undertaken with engineers and designers in the company to establish their knowledge of the design process and use of ergonomics in design. Several of the company’s installed designs were also evaluated to identify if the end product of the design process met ergonomics best practice. The results showed that the engineers and designers had poor knowledge of both the formal design processes in use in their company and how to apply ergonomics principles. The installed designs revealed several serious ergonomics problems that could impact on the operators’ ability to work efficiently and safely. Recommendations included improving the understanding and structure of the company’s design process, improving communication, providing adequate ergonomics resources, improving strategies for identification of ergonomics issues in designs and improving quality control of ergonomics issues. Relevance to industry In the well resourced and safety-aware environment of the oil and gas industry one would expect that ergonomics would be used to ensure that designs enhance operator efficiency and safety. The achievement of good ergonomic designs would also be expected to have substantial economic benefits in terms of reduced costs in manufacturing, training and maintenance ( Hendrick, 1997 , Good ergonomics is good economics. Ergonomics in Design). This study identifies minimal understanding or use of ergonomics by international engineers and designers and provides a reminder to all industries to evaluate how well they are using simple ergonomics principles and information.

Children have less variable postures and muscle activities when using new electronic information technology compared with old paper-based information technology

Children now have considerable exposure to new information technologies (IT) such as desktop computers. A reported association between computer use and discomfort in children has prompted concerns about the musculoskeletal stresses associated with computer use. There were no detailed data on children reading and writing, nor any evidence on the variability of postures and muscle activity whilst children use IT. Twenty-four children (10-12 years old; 12 male) performed a reading and writing task using new IT (computer/keyboard/mouse with high display and mid height display) and old IT (book/paper/pen). Spinal and upper limb 3D posture and muscle activity were recorded and estimates of mean and variation calculated. The mean postures for children reading and writing with computers were more neutral than when they read and wrote with old IT. Similarly, mean muscle activity levels were lower during computer use than old IT use. However, new IT use also resulted in less variable, more monotonous postures and muscle activities. Moderate differences in computer display height had little effect on posture and muscle activity variation. Variation in musculoskeletal stresses is considered an important component of the risk of musculoskeletal disorders. Children should therefore be encouraged to ensure task variety when using new IT to offset the greater posture and muscle activity monotony.

Children's Posture and Muscle Activity at Different Computer Display Heights and During Paper Information Technology Use

Objective: The 3-D posture and muscle activity in the neck and upper limb were assessed in children using high-, mid-, and book-level displays, which correspond to working conditions frequently observed when children interact with computers or books and paper. Background: The 3-D posture and muscle activity of children reading and inputting data with computers and paper had not been previously assessed. Methods: Twenty-four children aged 10 to 12 years and of normal height performed an interactive task involving reading from a book and writing on paper or reading from a computer display and inputting data using a mouse and keyboard. Results: Head and neck flexion increased as the visual target was lowered. The high display resulted in mainly upper cervical relative extension, and the book display resulted in both upper and lower cervical flexion. The book condition resulted in greater cervical erector spinae and upper trapezius activity than did the mid and high conditions. Conclusion: The data suggest that a mid-level display may be more appropriate for children than a high display (e.g., when the display is placed on top of the central processing unit). The mid display also results in a more upright and symmetrical posture and lower mean muscle activity than does working with books and paper flat on the desk. Application: This study provides short-term laboratory study evidence for the formulation of guidelines for workstation design and adjustment for children. Use of computers by children is increasing, yet ergonomic guidelines lag behind those for adults.

The influence of desk and display design on posture and muscle activity variability whilst performing information technology tasks

Desk design and computer display height can affect posture and muscle activation during computer use. Amplitudes of postural variables and muscle activity during computer use do not explain the results from epidemiological studies of musculoskeletal discomfort and disorders related to computer use. The purpose of this study was to assess variability of posture and muscle activity during work with two computer display heights and book/paper, in conjunction with a curved desk designed to provide forearm support and a traditional, straight desk. 18 male and 18 female participants performed 10-min tasks involving keying, mousing, reading and writing in six desk/display conditions. 3D posture and surface emg were assessed for the final 2 min of each task. The curved desk resulted in greater postural and muscle activity variation, suggesting an advantage of this supportive surface over the straight desk. There was little difference in variability associated with the two display heights. However, greater variability of posture and muscle activity was evident with the book/paper condition. Non-touch typists had greater neck flexion variation. The design of information technology tasks and workstations can influence the short term variation in posture and muscle activity. Variation is influenced independently of mean postures and muscle amplitudes and therefore needs to be considered to adequately assess the risk of musculoskeletal disorders.