The Industrially Developing Countries (IDC) today, to a great extent, depend on Industrialized Countries (IC) for the supply of most industrial goods. An attempt has been made to ascertain the degree of design incompatibility experienced by users of these imported goods due to differences in the body sizes of people in producer and user countries. A comparative study of variations in body sizes is made from data available in literature and from anthropometric surveys. The results reveal differences in almost every part of the human body. The need for reliable anthropometric data in respect of IDC is stressed. Urgent measures are required to introduce changes in equipment, particularly for the benefit of users in IDC.

It is beyond doubt that high technology has elevated the standards of living of mankind. The modern technology created and developed to a great extent by Western or developed societies is now in great demand in Eastern and developing societies who are trying to leap-frog towards advancement. But unfortunately, in the transfer of technology, both the giver and the receiver seem to make many mistakes. A technology transferred without considering the ethnic variables in the societies and differences in the climates, has found to cause problems to the acquirer. Due to the basic human factor differences such as sizes of people, physical environment, physical capacities and organizational and cultural differences, a technology which is unadapted has found to be inappropriate, harmful, hazardous and unsuccessful. In the areas of health, working conditions, production and finance, undesirable effects have resulted through haphazard technology transfer, For a successful transfer, it is therefore stressed that technology has to be adapted or modified taking into consideration the technological, anthropological and socio-economic factors of the acquiring population

Slips and falls on icy roads often result in fractures or sprains and is a major problem in Nordic countries. Walking trials by 25 subjects wearing four types of winter shoes on five different icy walking surfaces provided subjective and objective measures of tendency to slip and number of slips, respectively. Since friction is a major determinant of a slip, the influence of material spread on icy surfaces, the surface temperatures and the shoe soling characteristics versus the Coefficient of Friction (COF) of the shoes were measured. Sand and gravel on icy roads had positive effects on improving COF. The study revealed that the aetiology of slips and falls is multi-faceted and attempts to solve the problem must adopt a systems approach. Perception of risk, aging, training, experience and postural balance are other factors to be considered in preventing slips and falls. Future research should concentrate on the degree of impact of each factor to the aetiology of slips and falls, which can help to decide priority action in preventing slips and falls.

The effects of training in fuel-efficient driving for bus drivers in a city environment were evaluated. Three dependent variables, hypothetically associated with such training, were used; fuel and accident data from the bus company, and driver acceleration behavior from five buses, over time periods of several years. Effects of temperature and number of passengers on fuel consumption were held constant. Fuelling and acceleration data yielded fairly similar results. It was found that, although the effects on these variables during training were very strong (as found in a previous study), these did not transfer well into the drivers' working situation. Overall, the effect was about two percent fuel consumption reduction as a mean over 12 months after training. No effect was found for accidents, although a two percent reduction would not have been detectable. In a second phase of the study, 28 buses were equipped with Econen feedback equipment, which give an indication on how much fuel is used concurrently, resulting in a further reduction of consumption of about two percent.

Effects on physical workload were quantified when introducing new information technology in air traffic control. Seven female and seven male air traffic controllers were studied in an old control system, and during simulated - but similar - work in a new, mouse-based system. Postures, movements and muscular load were recorded (inclinometry for head, neck, back and upper arms; goniometry for wrists; electromyography for the trapezius and forearm extensor muscles). The new system was associated with lower movement velocities than the old one (examples; [50th percentiles] head flexion: 2 vs. 5 o/s, P<0.01; right arm elevation: 3 vs. 6 o/s; P<0.01; [90th percentile] wrist flexion: 19 vs. 50 o/s, P<0.01), less varying postures (head: 95th-5th percentile range 17° vs. 34o; P<0.01), and less muscular rest in the right forearm extensors (3.5 vs. 9% of time; P<0.05). The old/new system differences were amplified at high work intensities. The new air traffic control system caused a major change of physical exposures, probably associated with an increased risk of musculoskeletal disorders in arms and hands.

Relevance to industry

While this study concerned the specific changes in the introduction of a new air traffic control system, we believe that the findings are applicable to similar technological developments in other settings.

Ergonomic improvements of work station design have been widely embraced as a measure for reduction of physical work load (mechanical exposure) and prevention or control of occupational shoulder-neck disorders. However, other elements of work rationalization, more in the hands of production engineers, may also influence the mechanical exposure. The present study concerns shoulder-neck exposure in a Chinese and a Swedish assembly line workplace. Interactive effects of ergonomic work station design, and production engineering (in terms of assembly line balancing and sensitivity of assembly line layout to production irregularities) on shoulder-neck exposure have been studied. It was shown that the Swedish workplace has a better ergonomic work station design, reflected in more favorable work postures during assembly operations. At the same time, the Swedish assembly line is better balanced and less sensitive to production irregularities, which probably reduces the total duration of idle time during assembly compared with the Chinese line. On the Swedish assembly line, arm movements are more frequent, and trapezius and infraspinatus muscle activation is more repetitive. Muscle activation levels are similar on the two lines. However, a larger proportion of low level muscle activities were found on the Chinese line compared with the Swedish line. On the basis of these results, it is suggested that the mechanical exposure of the assembly workers is a result of counteracting effects of improved ergonomic design of work stations and more effective production engineering.

This paper discusses a computer-aided planning methodology and its applicability for planning of industrial production and working environments as well as for planning of residential and working environments for the differently abled. The methodology has been developed and evaluated in six case studies in mechanical industries and in six case studies related to adaptations for the differently abled.The results from the case studies indicate that computer-supported modelling and visualisation may serve as a common and efficient language facilitating communication about multifaceted environmental planning issues. The methodology is a cost-effective way of demonstrating layout ideas and testing dynamic activities like manufacturing and transportation. Corporate groups comprising people involved in, or affected by, development work seem to be a fruitful approach for cooperation, one which enhances learning and creativity. Such groups may be a proper forum for the dissemination of information, exchange of opinions, utilisation of both expert and lay experiences, and for public testing of current reality or future plans in such a way that mutual understanding between different professional categories is increased, hence promoting internal commitment.Relevance to industryThe success of design projects depends both on their quality from a technical and economic point of view, and on the quality of their implementation and use. This paper discusses a computer-aided planning technique and its applicability and quality in both these respects. The technique is developed for planning of industrial working environments and for planning of residential and working environments for the differently abled.

In order to develop usable products, human needs and requirements have to be taken into consideration. By employing the QFD (Quality Function Deployment) method the human needs are systematically matched with the product characteristics, which can help to improve the product quality. In this paper the use of QFD in the area of ergonomics is discussed and a case study is presented, The QFD method was used in the case study to translate the needs of safety shoe users in the cold climate into product characteristics. The QFD analysis of the safety shoes revealed that the characteristics of the steel toecap were receiving the highest overall weighting, which means that improving the design of the steel toecap would lead to higher customer satisfaction. Relevance to industryThe importance of developing products that meet the customer or human needs is a priority area in the product development process. With knowledge in ergonomics it is possible to reveal information of the human needs and requirements. However, in the product development process it also is important to match the human needs with the product characteristics, which can be achieved by using the QFD method. The knowledge of ergonomics and the use of the QFD method are therefore useful tools in designing high quality products.

Manufacturing corporations sometimes use corporate-internal procedures to evaluate and monitor the ergonomic status of the workplace. This article describes an industrial case study in the Swedish automotive sector, where an internally developed evaluation procedure was compared with a procedure based on a Swedish national standard provision.

It was found that the national standard procedure tended to give more severe ratings and statistical support shows that the two evaluation procedures are not equivalent. The ability of the methods to identify body segments at risk was also compared.

The quantitative comparison was followed up with interviews, where the influence of professional tasks and objectives became evident, as well as the fact that evaluation criteria are quantified differently by the two procedures. The main finding is that unforeseen differences in analysis procedure, criteria of acceptability and levels of detail can cause use-related difficulties for different professional groups when methods are used interchangeably.

Relevance to industry: Industrial corporations wishing to monitor ergonomics consistently are advised by the authors to ensure that ratings from internal evaluations are interpreted the same way by all involved personnel, and that they at least have criteria levels equivalent to those of a national standard.

The benefits of having users evaluate product or workplace design during the development process are well known. This is often achieved by letting users interact with one or more models of the design proposal, in order to elicit feedback. The issue for product developers is to choose what type(s) of models to use (from paper drawings to physical or virtual mock-ups or fully working prototypes) and when to use them in the development process, while making optimal use of resources like time, money and personnel.

This paper compares three types of simple three-dimensional (3D) models (1:1 scale, 1:16 scale and CAD) representing a ship bridge workstation, examining what kind of feedback they elicit in a design evaluation with representative users. Participants were asked to assess the proposed design and to compare the models' relative merits. The study found that while all three types of 3D models elicited several types of useful design feedback, there were differences in both quantity and content of the feedback elicited by each model type. The physical models elicited more feedback than the CAD model, both regarding content richness (direct and indirect design feedback) and quantity. The tangibility of the models seems to greatly influence acceptance and credibility.

Relevance to industry: There is emerging evidence of musculoskeletal problems related to smartphone work and a rapid transition to mobile workplaces, where smartphones are key working tools. Aim: The study's aim was to compare muscle activity during computer work with smartphone work and to see what possible effects ergonomic recommendations for smartphone usage have on muscle activity. Methods: Activity was measured bilaterally from the upper trapezius muscle and from lower arm muscles on the right hand side, on twelve participants with surface electromyography who performed e-mail work on the computer using ergonomic recommendations, smartphone in a self-chosen way of working and on smartphone with ergonomic recommendations. Effects on productivity was not assessed in this study. Results: Activity in m. trapezius and m. extensor digitorum was significantly higher during computer work (p < 0.05) than during the two smartphone usages and activity in m. interossei dorsalis 1 was, vice versa, significantly higher during smartphone work fp < 0.05). Comparison of smartphone in self-chosen way of working and smartphone with ergonomic recommendations showed no significant differences. Conclusions: Previous research has highlighted the benefits of variation of work postures. This paper indicates that replacing the computer with a smartphone gives the trapezius muscle an opportunity to rest.

This paper presents the development of an adaptive linear regression model for synthesizing of missing anthropometric population data based on a flexible set of known predictive data. The method is based on a conditional regression model and includes use of principal component analysis, to reduce effects of multicollinearity between selected predictive measurements, and incorporation of a stochastic component, using the partial correlation coefficients between predicted measurements. In addition, skewness of the distributions of the dependent variables is considered when incorporating the stochastic components. Results from the study show that the proposed regression models for synthesizing population data give valid results with small errors of the compared percentile values. However, higher accuracy was not achieved when the number of measurements used as independent variables was increased compared to using only stature and weight as independent variables. This indicates problems with multicollinearity that principal component regression were not able to overcome. Descriptive statistics such as mean and standard deviation values together with correlation coefficients is sufficient to perform the conditional regression procedure. However, to incorporate a stochastic component when using principal component regression requires raw data on an individual level.

Relevance to industry

When developing products, workplaces or systems, it is of great importance to consider the anthropometric diversity of the intended users. The proposed regression model offers a procedure that gives valid results, maintains the correlation between the measurements that are predicted and is adaptable regarding which, and number of, predictive measurements that are selected.

Summary The mechanical impedance of the hand and arm was studied on ten healthy subjects during exposure to sinusoidal vibration within the frequency range of 2 to 1000 Hz. A special handle for the measurements was constructed. The influence of vibration direction, handle grip, grip force, vibration level, hand-arm posture and sex as well as anthropometric data were studied. The results show that the impedance of the hand-arm mainly depends on the frequency and direction of the vibration stimuli. Higher vibration levels, as well as more firm hand-grips, resulted in higher impedance. Furthermore, the outcome shows that experiments conducted with different hand-arm postures had an active influence on the mechanical impedance. Moreover, the subjects' sex and constitution of the hand and arm affected the impedance to a large extent.

In recent years there has been a discussion as to whether shock-type vibration from hand tools has stronger effects on the hand-arm system in comparison with non-impulsive vibration. The purpose of the investigation is to compare the influence of these two types of vibration on the absorption of mechanical energy in the human hand and on the grip and feed forces applied by the subjects.The energy absorption has been measured by use of a specially designed laboratory handle. The grip and feed forces applied by the subject to the handle were measured simultaneously. In the study two different frequency weighted acceleration levels were used.The outcome showed that the vibration exposure levels made a significant contribution to the vibration absorption as well as to the strength of the grip and feed forces. Moreover, it was found that the hand forces decrease while the absorption of energy increases during the experiment. Furthermore, the influence of shock-type exposure gave a significantly higher hand forces and absorption of energy compared with the non-impulsive exposure. It was, therefore, concluded that the vibration response characteristics of the hand and arm differ, depending upon whether the exposure is of shock or non-impulsive type.Relevance to industryThe paper discusses the dynamic response of the hand and arm during exposure to shock and non-impulsive vibration. Whenever possible, a tool that requires low grip and feed forces should be used as well as tools that not generate shock-type excitation. This can be helpful in choosing the proper tool for the job.

This article presents a materials kitting case study, using an alternative method for materials kitting: the traditional picker-to-material principle was replaced with a material-to-picker approach. The study was made in a materials supply workshop of an automobile plant shortly after this kitting process had been introduced. The materials kitting was video recorded and the material pickers’ physical exposure was assessed using ambulatory equipment to make an integrated registration of muscular activity, work postures and movements. The material pickers assessed work situations perceived as physically stressful. The materials kitting showed improved productivity as compared with other kitting methods. The study indicated that the work situation offered pickers low levels of physical exposure. The picking work was rather light but involved great repetitiveness in arm movements. The material pickers experienced the work as repetitive and having some physically stressful work situations. The integrated analyses showed: (1) that exposure in picking operations was similar to, but could be distinguished from, other work activities and (2) that picking from one type of storage package, Euro pallets, resulted in higher exposure than picking from plastic containers. More studies are needed on the implications of exposure levels in materials picking.

We examined the effect of a low-level sustained contraction on the muscle contractile properties, hemodynamics and oxygenation of the flexor digitorum superficialis muscle (FDS) of the finger. We tested the hypothesis that hemodynamics and oxygenation, reflecting the muscle metabolic characteristics, would recovery more quickly than the muscle contractile properties. Eleven subjects (26 ± 4 yrs) were equipped with electrodes for electrical stimulation and a near-infrared spectroscopy (NIRS) probe on the forearm over the FDS. The experimental protocol consisted of three baselines measurements (-60 min, -30 min, pre-exercise), immediately after a sustained 15-min contraction of the FDS at 10% maximal voluntary contraction (post-exercise), and after 30 min, 60 min and 120 min of recovery. For each time point, participants were subjected to a battery of test that included upper arm venous occlusion (at rest), a computer-mouse point and click task (standardized voluntary task), and electrical stimulation. For venous occlusion (50 mmHg, 1 min), slopes were calculated for NIRS-derived total hemoglobin (HbTslope) and deoxyhemoglobin (HHbslope) as estimates of blood flow and oxygen consumption, respectively. The computer-mouse task entailed using the mouse to point and click on targets presented on the screen during which NIRS signals were monitored for determination of change in total hemoglobin (ΔHbT) and oxygen saturation (ΔStO2%). Electrical stimulation (2 Hz, 5 trains of 15 twitches) provided twitch force (Tw-force), contraction time (CT) and one-half relaxation time (½RT) data. Statistical analysis revealed significant changes over time for all contractile parameters as well as for HHbslope (P < 0.05 for each). Post-hoc testing demonstrated significant decreases for Tw-force post-exercise and at 60 min; for CT at post-exercise, 30 min and 60 min; and for ½RT at post-exercise and at 30 min. HHbslope was significantly higher post-exercise as compared to pre-exercise. During the computer-mouse point and click task, no significant differences were detected forΔHbT, however,ΔStO2% showed a tendency to decrease, albeit not significant (P = 0.11). Further testing showedΔStO2% was significantly lower post-exercise and at 30 min as compared to pre-exercise. The present study shows that NIRS provides insight into muscle hemodynamics and oxygenation for low-level sustained activity to fatigue. The overall quick recovery of hemodynamic and oxygenation responses, and a more prolonged recovery of contractile responses confirms our hypothesis, and this may fit well with the classical definition of low frequency fatigue.

The aim of the present study was to investigate how changed work organisation and different work tasks influence shoulder muscular load and to quantify the magnitude, duration and frequency of rest periods from shoulder muscular load during a working day. Shoulder muscular load was measured in 22 females working at their data entry workplaces, during a whole working day. The activity from both trapezius muscles was measured with EMG before (1991) and after (1992) a reorganisation programme intended to redistribute repetitive work and provide new work tasks.The change in work organisation did not change the magnitude of muscular load or the duration and frequency of rest periods, but decreased musculoskeletal problems. The subjects' increased desk work involved greater muscular load than the data entry did, but also allowed more movement. The changes in work tasks seemed to be important, although small. In repetitive work, organisational changes aimed at reducing musculoskeletal disorders should focus on providing employees with tasks that afford variation in muscular load. Relevance to industry. The paper discusses the need of physical work task variation in repetitive work in order to minimise the risk of musculoskeletal disorders. It seems more important to vary the tasks than to minimise the shoulder muscular load. Copyright

Footwear sole wear by natural use or artificial abrasion either increases or decreases slip resistance on floors with and without lubricant. The objectives of this paper were to study the effect of footwear sole abrasive wear on slip resistance on ice with respect to temperature, and to compare the slip resistance of abraded soles on melting and hard ice with that on lubricated steel plate. The kinetic coefficient of friction (COF) of nine pairs of footwear were measured with the stationary step simulator developed at the Finnish Institute of Occupational Health, before and after the new footwear soles were artificially abraded. Two-way factorial ANOVA showed that the abrasion of nine pairs of footwear had no significant effect on COF on melting ice (Mean COF with abrasion=0.056, std=0.0158, COF without abrasion=0.055, std=0.0205, P=0.805). On hard ice, however, the COF of abraded soles measured (mean COF=0.244) was significantly higher than without abrasion (mean COF=0.180,p<0.001), and than abraded soles on lubricated steel (mean=0.137,p<0.001). There is statistical significance between the three types of surfaces (P<0.001). On hard ice, regardless of abrasion, curling footwear with crepe rubber soling showed significantly higher COF (mean=0.343 after abrasion, 0.261 before abrasion) than other types (P<0.001). The results indicate that artificially abraded footwear is more slip resistant than new one for use on hard ice. The abrasion requirement could be specified if developing a new standard to measure COF on ice in the future. Of the footwear measured, the curling footwear with crepe rubber soling performed best in terms of slip resistance property. Therefore, Crepe rubber soling is highly recommended for use on hard ice. Melting ice is much more slippery, in which sole abrasion does not improve slip resistance. Thus, additional measures should be taken to reduce slip and fall risk. Relevance to industrySlipping and falling accidents are common on surfaces covered with snow, ice, melting snow, melting ice or the mixed in winter for outdoor workers and pedestrians. Understanding of the friction at the interface can help footwear industry design slip resistant products, to help outdoor workers choose appropriate protective equipment, and to provide safe work practice for industries involving outdoor work.

The aim of the paper is to map out how the operator limits the productivity in mechanised spacing and cleaning of young stands of trees. The work elements in this forestry machine work are analysed simultaneously with the measuring of the operator's workload. Proposals for technical developments are given. The design of the study follows a model which secures control of important occurring factors.Operating a forestry cleaning and spacing machine is probably the most intensive forestry machine work. The low heart rate variability indicates a high mental workload. The intense operation of the crane causes few pauses (EMG-gaps) in the trapezius muscle. Managing the machine occupies the operator's attention while biological assessments of the stand are needed. Neck and shoulder complaints are still a major problem.To keep mechanised cleaning profitable, machine, crane and cleaning head must be easier to handle. A partly robotized crane and cleaning head and better sight can help the operator to perform faster and more reliable cleaning. A self-levelling cab with a pivoting ability will give the operator a more relaxed working environment. In the future perhaps a cleaning and spacing robot might be a choice.

This study deals with human fingers touching cold surfaces of four materials (aluminium, steel, nylon and wood) at different surface temperatures (-20°C, -15°C, -10°C, -4°C, 0°C and 2°C). Contact finger skin-surface interface temperature and subjective responses on thermal and pain sensations were determined during touching. Type of material and their surface temperature clearly affected the contact cooling of the finger. Individual variation in finger contact cooling was significant. Contact temperature limits for human fingers touching cold surfaces are suggested according to the experimental results. In addition, time to reach a critical temperature (7°C, 5°C or 0°C) when contacting a cold metallic surface is discussed.

Computer work is a visually demanding task associated with adverse eye symptoms. Frequent use of digitaldisplays is known to cause a deterioration of the so-called binocular control. Direct glare further reduces thecapacity for binocular coordination during computer work, leading to reduced reading ability and increased eyesymptoms.The purpose of this study was to investigate the effect of different luminance levels of direct glare on binoculareye movement control and reading ability in a computer work environment.Sixteen participants with normal binocular vision performed equal reading tasks in a balanced study. Threecontrolled lighting conditions of direct glare (2000, 4000 and 6000 cd/m2) were tested, in addition to no glare.After each trial, the participants answered survey questionnaires regarding their understanding of the text, aswell as their subjective experience of workload and perceived vision. Horizontal fixation disparity (FD) wasmeasured before and after the reading tasks to evaluate binocular eye movement control.When comparing the responses of visual experience, a significant difference in reported eye symptoms wasfound between lighting conditions. Based on the variation (SD), a significant difference was found within meanvalues of repeated measurements of horizontal FD and a significantly higher variation in a comparison of initialFD values measured during lighting conditions of no glare, to final measured values in all three glare conditions.Reading ability was found to be significantly negative affected with the adversity of lighting conditions.This study supports the contention that binocular eye movement control is reduced caused by direct glare.Even lower degree of disability glare caused eye symptoms. The results establish the argument that working withflat screens raises visual demands.

The purpose of this study was to analyze the effect of ac ute vibration exposure on manual performance. Ten experienced healthy carpenters performed three standardized common tasks (nailing, sawing, screwing). EMG activity was recorded from six arm-shoulder muscles/muscle group using surface electrodes, and the performances were video-filmed. The subjects also reted their exertions. After ten minutes of standardized vibration exposure (50 Hz, 20 m/s2) the tasks were repeated. The number of work movements and the time taken for each task were recorded. In addition the quality of the work performed after the first and second trials was compared. Changes in muscle activity were mainly increased activity in trapezius. The most active muscles, with EMG mean values exceeding 10% EMGmax, were trapezius (mean values 9-21% EMGmax, infraspinatus (mean 6-18% EMGmax) and flexor digitorum (mean 15-21% EMGmax). Only rating perceived exertion while nailing was higher after vibration. Vibration exposure seemed to be very individually perceived. Short-time exposure did not seem to influence the performance of well-known tasks.

Car developers use digital human modeling tools to analyze and visualize car interiors in relation to human characteristics before the vehicles are actually constructed. Developers, reviewers and users of human simulation tools often claim that such tools can reduce development time and costs. In car industry companies today, human simulation tools are used by a single or a few experts in an informal working process with insufficient documentation. To prepare for extensive, effective and efficient use of human simulation modeling tools in industry with several users within a company, the aim of this study was to design and evaluate a digital guide and documentation system to support digital human modeling applications. A participative design approach was used in developing the guide, involving human simulation tool users and managers within the General Motors Group. The system consists of two major parts: a usage guide and database. The usage guide is divided into three sections considering the professionals involved: (1) initiation of human–vehicle interaction analysis, (2) preparation and running of the digital human tool and (3) recommendation formulation and closure. The guide was connected to a database with search and print capabilities for previous and ongoing human simulation analyses. Sixteen subjects from industry and university settings evaluated the support system. Results showed that the users appreciated the guide and documentation system, in particular, the database for storing human simulation work. The guide was perceived as being especially useful for guidance in large analyses, whereas for smaller ones the subjects felt the formalized guide was too lengthy and time consuming. The use of the formalized guide is likely to reduce differences in results, within and between tool users. The support system guides the simulation tool user through an acknowledged process; it documents, stores and keeps track of ongoing and previous analyses, and facilitates the reuse of studies.

The car interior is a complex man–machine interface. Poor interior design contributes to traffic accidents as well as discomfort and disorders in professional and long distance drivers. When buying a car comfort is for many customers an important factor. Consequently, car interior comfort besides safety is of great importance when designing cars. Comfort is a subjective feeling and hard to model mathematically. The aim of this paper is to show the feasibility with fuzzy logics to model relations between human perception, human characteristics and workplace structure. A model where drivers’ perceived comfort when handling interior controls is in relation to anthropometrics and control positions are used as illustration. A series of control reach studies in simulated car driving was used for the development of a comfort model. Combined with a human simulation program the comfort model may be used by car designers at an early stage of the design process for evaluation of design concepts aiming at reachable and manageable controls in a safe and comfortable interior. The comfort model illustrates that fuzzy logics provides a constructive way of turning qualities into mathematics.

Relevance to industry: Fuzzy logics provide the opportunity to model physical parameters from the human and the technical system together with human perceptions. Such model can be combined for instance with human simulation tool and reduce ergonomic tests in real physical environments.

Objective

To describe the development of a computer-based risk assessment method for visual ergonomics, and assess its face validity, content validity, and internal consistency.

Methods

The risk assessment method contained a questionnaire for the worker, an evaluation form for the evaluator, a section of follow-up questions based on the worker's responses, and a section for recommended changes, including an overall risk assessment with respect to daylight, lighting, illuminance, glare, flicker, work space, work object and work postures, respectively. Forty-eight trained evaluators used the method to perform 224 workplace evaluations. Content validity of the method was assessed by the completeness and distribution of responses, and internal consistency was assessed by Cronbach's alpha, Spearman's rank correlation between items and indices, and exploratory factor analysis.

Results

The proportion of missing values in items was generally low (questionnaire: 0–2.3%; evaluation form: 1.4–4.1%). In the questionnaire, items about double vision, migraine and corrective lenses had limited information content. Cronbach's alpha and item-index correlations for the indices frequency of eyestrain, intensity of eyestrain, visual symptoms, lighting conditions, frequency of musculoskeletal discomfort and intensity of musculoskeletal discomfort were satisfactory. Based on the factor analysis, suggestions for improving some of the indices were made.

Conclusion

Our findings suggest that this computer-based method is a valid instrument for assessing risks in the visual work environment. By incorporating subjective ratings by the worker as well as objective measurements of the work environment, it provides a good basis for recommendations with respect to daylight, lighting, work surfaces/material, and work object.

Relevance to industry

Visual environment factors, such as glare, can cause eyestrain, headache and musculoskeletal discomfort. This method satisfies the need of a valid tool for determining risks associated with the visual work environment. It contains both worker's ratings and objective measurements, and is designed to be used in different types of work.

[No abstract available]

Health information technology (IT) is widely endorsed as a way to improve key health care outcomes, particularly patient safety. Applying a human factors approach, this paper models more explicitly how health IT might improve or worsen outcomes. The human factors model specifies that health IT transforms the work system, which transforms the process of care, which in turn transforms the outcome of care. This study reports on transformations of the medication administration process that resulted from the implementation of one type of IT: bar coded medication administration (BCMA). Registered nurses at two large pediatric hospitals in the US participated in a survey administered before and after one of the hospitals implemented BCMA. Nurses' perceptions of the administration process changed at the hospital that implemented BCMA, whereas perceptions of nurses at the control hospital did not. BCMA appeared to improve the safety of the processes of matching medications to the medication administration record and checking patient identification. The accuracy, usefulness,, and consistency of checking patient identification improved as well. In contrast, nurses' perceptions of the usefulness, time efficiency, and ease of the documentation process decreased post-BCMA. Discussion of survey findings is supplemented by observations and interviews at the hospital that implemented BCMA. Relevance to industry: By considering the way that IT transforms the work system and the work process a practitioner can better predict the kind of outcomes that the IT might produce. More importantly, the practitioner can achieve or prevent outcomes of interest by using design and redesign aimed at controlling work system and process transformations.

This study was conducted in order to analyse checkout cashiers’ movements at a checkout counter during interaction with customers and the prevalence of work-related stress and musculoskeletal disorders in checkout cashiers. In one shop, six cashiers were videotaped during the workday, and 50 cashiers from seven shops from the same chain of stores responded a questionnaire. Cashier activities and movements, customer interaction and counter design issues were analysed from the video data. Prevalence of work-related stress and musculoskeletal disorders was obtained from the questionnaire. It was found that 76% of all items were manually turned or angled. With a better adjustment of the scanner and a standardised positioning of the EAN-code, many of these movements could be avoided. Furthermore the prevalence of musculoskeletal disorders was quite high (68% for the neck). The questionnaire results showed that many cashiers experienced stress, giving a high percentage of cashiers in the “dedication under pressure” group. The behaviour of the customers was the major cause of stress. Other sources of stress arose from bad design or function of the computer system or other technical equipment.

Relevance to industry: In this study several problems regarding cashier work were identified and solutions, relevant to counter and package designers, shop managers and cashiers are suggested. Data obtained on cashier movements and prevalence of musculoskeletal disorders are given.

This study was conducted in order to analyse checkout cashiers’ movements at a checkout counter during interaction with customers and the prevalence of work-related stress and musculoskeletal disorders in checkout cashiers. In one shop, six cashiers were videotaped during the workday, and 50 cashiers from seven shops from the same chain of stores responded a questionnaire. Cashier activities and movements, customer interaction and counter design issues were analysed from the video data. Prevalence of work-related stress and musculoskeletal disorders was obtained from the questionnaire. It was found that 76% of all items were manually turned or angled. With a better adjustment of the scanner and a standardised positioning of the EAN-code, many of these movements could be avoided. Furthermore the prevalence of musculoskeletal disorders was quite high (68% for the neck). The questionnaire results showed that many cashiers experienced stress, giving a high percentage of cashiers in the “dedication under pressure” group. The behaviour of the customers was the major cause of stress. Other sources of stress arose from bad design or function of the computer system or other technical equipment. Relevance to industry: In this study several problems regarding cashier work were identified and solutions, relevant to counter and package designers, shop managers and cashiers are suggested. Data obtained on cashier movements and prevalence of musculoskeletal disorders are given.

The factors initiating aviation accidents are usually hidden behind various steps, systems, and tasks, and systematic root-cause analysis is required to uncover the initial factor(s). To reduce the risk of unfavourable events, it is more appropriate to study their causal factors. We argue that an in-depth study on maintenance process deviations could assist in uncovering hidden causal factors. We therefore analyse reported maintenance deviations from an aviation organisation using the Human Factor Analysis and Classification System-Maintenance Extension (HFACS-ME) taxonomy to aggregate and map hidden causal factors. We find attention and memory errors and inadequacy of processes and documentation are major causal factors. We argue a well-run organisation can capture hidden causal factors and reduce the risk of incidents and accidents. More specifically, we show how situation awareness (SA) interventions can assist in the mitigation of maintenance deviations and capture hidden causal factors.

The main aim was to examine the effects of measurement depth on tissue oxygenation, and haemoglobin kinetics in the oxidative supraspinatus/trapezius muscle and in the deltoid muscle. Seven female subjects performed dynamic arm abductions (0.5 Hz) with an external load of 1.2 kg at level of the elbows. Tissue oxygenation (StO2) expressed as %StO2 saturation, total haemoglobin (HbT) , oxyhaemoglobin (HbO2) and deoxyhaemoglobin (Hb) were measured in two different measurement depth using near infrared spectroscopy (NIRS). HbT reflects blood volume. Measurements were performed simultaneously in the supraspinatus/trapezius and in the anterior part of the deltoid muscles.

The average StO2 level at rest was in general lower in the supraspinatus/trapezius muscles (67.7(5.3) % StO2) than in the deltoid muscle (85.4(4.4) % StO2). Submaximal dynamic arm abductions resulted in decreased StO2 in both muscles. However, the initial decrease was steeper and larger for the deltoid muscle than for the supraspinatus/trapezius region. Correspondingly, the initial reoxygenation in the recovery phase was faster for the deltoid muscle than for the supraspinatus/trapezius muscle.

At rest no differences in StO2 were found with increasing measurement depth in any of the two muscles. However, during exercise StO2 decreased with increasing measurement depth in the deltoid muscle whereas StO2 was more homogeneous in the supraspinatus/trapezius muscle.

Furthermore, HbT and HbO2 were largely maintained in the supraspinatus/trapezius muscle whereas HbT and HbO2 decreased during exercise and with increasing measurement depth (HbT) in the deltoid muscle. Hb increased during exercise in both muscles.

The hemodynamic differential responses to exercise for the two regions may reflect a combined effect of differences in muscle fibre composition and a dependency of depth related changes in the intramuscular pressure during exercise. Thus, the supraspinatus/trapezius muscles seems to be more

efficiently adapted to the oxygen demand during submaximal dynamic exercise than the deltoid muscle although the intramuscular pressure during the contractions is expected to be higher in the supraspinatus muscle than in the deltoid muscle.

In conclusion, muscle hemodynamic responses to dynamic exercise are highly muscle specific and may be spatially homogeneous or inhomogeneous depending on the muscle

The aim of the present study was to describe working conditions and the prevalence of musculoskeletal symptoms among male and female VDU operators, and to assess associations between work-related physical and psychosocial exposures and neck and upper limb symptoms by gender. The study population comprised a variety of occupations from both private and public sectors. Data on physical and psychosocial exposures were collected by questionnaires, as were data on musculoskeletal symptoms. Univariate associations between exposures and symptoms affecting the neck and upper limbs were estimated by calculating the prevalence ratios with 95% confidence intervals. We also assessed the potential excess odds ratio attributable to interaction between gender and, one by one, exposure variable. Women (n = 785) used the computer on average 3.9 h/day and men (n = 498) 3.6. Variation of different work tasks was lower among females than among males. Nineteen per cent of the women and 12% of the men did > 3 h of continued computer work without breaks (> 10 min) at least twice a week. Twice as many women as men experienced high job strain (high demands and low decision latitude). A higher proportion of women than men reported symptoms greater than or equal to 3 days the preceding month from the upper body, irrespective of body region. For many of the studied exposures the prevalence of symptoms in one or several body regions was increased with increasing exposure, indicating exposure-response relationships. Duration of computer work was associated with symptoms among both men and women. Only among men, duration of work with a non-keyboard computer input device was associated with symptoms. Only among women, job strain was associated with symptoms. Time pressure was associated with higher prevalence of symptoms among women. Among men, time pressure was associated with lower prevalence of symptoms. Thus, the associations differed between the genders. Women experienced higher prevalence of symptoms than men in all body regions and they were more often exposed to physical and psychosocial conditions that in previous studies have been considered harmful, than men.

Posture (optoelectronic 3D motion analysis system), muscular load (EMG), perceived exertion (rating scales), preference and productivity were investigated in 20 healthy VDU-operators (10 male and 10 female) during text editing with two different data input devices, a mouse and a track-ball. Work with the track-ball entailed lower shoulder elevation and less neck/shoulder muscle activity than work with the mouse. Arm support reduced muscle activity in the neck/shoulder region irrespective of input device used. A table height lower than 3 cm above elbow height allowed arm and shoulder support without undue shoulder elevation. Work with the track-ball entailed more wrist extension than work with the mouse. Perceived exertion ratings were lower for the shoulder and higher for the hand with track-ball than with mouse operation. Thus, biomechanical demands differ between different input devices. The women elevated and rotated their right shoulder outwards more than the men during work with both input devices. The overall EMG results showed a higher activity among the women than among the men in two of the examined muscles. This may relate to anthropometric differences which also influence biomechanical load moments. Another reason could be the observed differences in working techniques between the men and the women.

The aim of the present study was to describe working conditions and the prevalence of musculoskeletal symptoms among male and female VDU operators, and to assess associations between work-related physical and psychosocial exposures and neck and upper limb symptoms by gender. The study population comprised a variety of occupations from both private and public sectors. Data on physical and psychosocial exposures were collected by questionnaires, as were data on musculoskeletal symptoms. Univariate associations between exposures and symptoms affecting the neck and upper limbs were estimated by calculating the prevalence ratios with 95% confidence intervals. We also assessed the potential excess odds ratio attributable to interaction between gender and, one by one, exposure variable. Women (n=785) used the computer on average 3.9 h/day and men (n=498) 3.6. Variation of different work tasks was lower among females than among males. Nineteen per cent of the women and 12% of the men did >3 h of continued computer work without breaks (>10 min) at least twice a week. Twice as many women as men experienced high job strain (high demands and low decision latitude). A higher proportion of women than men reported symptoms 3 days the preceding month from the upper body, irrespective of body region. For many of the studied exposures the prevalence of symptoms in one or several body regions was increased with increasing exposure, indicating exposure-response relationships. Duration of computer work was associated with symptoms among both men and women. Only among men, duration of work with a non-keyboard computer input device was associated with symptoms. Only among women, job strain was associated with symptoms. Time pressure was associated with higher prevalence of symptoms among women. Among men, time pressure was associated with lower prevalence of symptoms. Thus, the associations differed between the genders. Women experienced higher prevalence of symptoms than men in all body regions and they were more often exposed to physical and psychosocial conditions that in previous studies have been considered harmful, than men.

The aim of this study was to assess the agreement between observers analyzing activity patterns during truck engine assembly work based on video recordings. Two observers observed the recordings of nine workers, on the average 2.2 hours long, assigning activities to four activity categories. For each activity category data were obtained on the mean duration of uninterrupted sequences of activities and their relative time proportion in the job. This data was analyzed with 2-way crossed ANOVA algorithms to derive the components of variance attributed to disagreement between observers, to differences between filmed subjects, and to residual “unexplained” variance. The latter was interpreted as an estimate of within-observer variability and possible interactions between subject and observer. While the observers disagreed about the overall time proportions for the four activity categories by no more than 3.7% of time, their second-to-second classification disagreed for 13% of the total analysis time. The between-observer variance was small as compared to within-observer variance and the variance between subjects performing the same job. Simulations based on the variance components showed that a group mean of the proportion of direct work could be determined with a standard deviation within 5% of the mean by having two observers analyzing one two-hour video recording once, each.

Relevance to industry

The results of this study may support decision making when designing a reliable video based analysis of industrial work. Thus, the study helps production engineers, ergonomics practitioners and researchers allocate resources between data collection and data analysis, based on their preferences for precision and power of a particular study.

This study was conducted in order to analyse checkout cashiers' movements at a checkout counter during interaction with customers and the prevalence of work-related stress and musculoskeletal disorders in checkout cashiers. In one shop, six cashiers were videotaped during the workday, and 50 cashiers from seven shops from the same chain of stores responded a questionnaire. Cashier activities and movements, customer interaction and counter design issues were analysed from the video data. Prevalence of work-related stress and musculoskeletal disorders was obtained from the questionnaire. It was found that 76% of all items were manually turned or angled. With a better adjustment of the scanner and a standardised positioning of the EAN-code, many of these movements could be avoided. Furthermore the prevalence of musculoskeletal disorders was quite high (68% for the neck). The questionnaire results showed that many cashiers experienced stress, giving a high percentage of cashiers in the "dedication under pressure" group. The behaviour of the customers was the major cause of stress. Other sources of stress arose from bad design or function of the computer system or other technical equipment. Relevance to industry: In this study several problems regarding cashier work were identified and solutions, relevant to counter and package designers, shop managers and cashiers are suggested. Data obtained on cashier movements and prevalence of musculoskeletal disorders are given.

This cross-sectional study of a group of assembly workers (n=289) tested the hypothesis that affective stress responses mediate the effect of psychosocial work conditions on musculoskeletal complaints (MSCs). Self-reported work demands, control, social support, stress, energy, and MSCs were analysed in hierarchical logistic regression analyses. High work demands were related to a higher risk of shoulder problems. Work demands and social support, but not control, were related to stress; and more musculoskeletal complaints were found in the group with high stress than in the low-stress group. The analyses supported the hypothesis that the effects of work demands on shoulder problems were mediated by the affective stress response, whereas this did not seem to be the case for the effect of social support and control conditions on neck problems. A weaker relation to psychosocial work conditions was shown for back problems than for shoulder and neck problems. Relevance to industry: Psychosocial work conditions have repeatedly been shown to be related to risk of musculoskeletal complaints. Individual subjective stress responses may help to identify those who are at risk with respect to shoulder complaints.

The study aimed to find out the problems connected with feet during work in cold loose housing barns in wintertime. Thirteen dairy farms and 20 workers were studied. Skin temperatures and subjective responses were collected, and at the end of a work period the subjects filled in a questionnaire about the workday. The foot skin temperatures were measured on dorsal foot and second toe. Most of the workers used rubber boots. The ambient temperature outdoors varied from +5 to -11°C. Indoor temperatures could be the same as outdoors (cold barns and fodder storage) but also close to +30°C (milk room). The lowest mean foot and toe skin temperatures were 24.1±2.6°C and 16.0±1.4°C. The lowest measured values were 20.1°C and 12.8°C, respectively. The toe temperatures were on average 7.3°C colder than foot temperatures (mean 28.8°C). The low foot skin temperature was well related to cold sensation. Low toe temperatures fitted well with wetness sensation. On average the thermal sensation of feet over the work period was neutral. The lowest ratings were cold (-2). The combination of various environmental factors in farms complicates finding of perfect footwear for work. Recommendations on the choice of footwear and their care are given.

This study investigated cold weather safety footwear and the possible thermal effects of steel toe caps in footwear. Two models of boots were used. Both models were manufactured in two variants - with and without steel toe cap. The boot insulation was measured with an artificial, heated foot (AHF). One model was used in experiment with subjects (n=6). Cold exposure consisted of sitting for 60 min at -10°C. There were no differences between insulation levels of boots with and without steel cap for one boot model, but the differences were statistically significant for the second model showing slightly higher insulation values for the boot without steel cap. No significant differences due to insulation dissimilarities could be found from the measurements on subjects. Statistically significant differences were found for both models regarding the rate of change of heat loss from AHF when its location was changed from warm to cold and back to warm. The rise and decrease of heat loss from AHF depended on the rate of temperature change of the boots. The results showed that a faster change in heat loss from AHF occurred for boots without steel toe caps. Data from subjects seemed to confirm this by a somewhat faster, though not significant, rise in toe skin temperatures after cold exposure in boots without steel toe caps. The effect may be attributed to the higher mass and heat contents of the boots with steel toe cap.

Methods: In this study, cleaning process was studied and analyzed with special reference to cleaning tools. A group of 13 professional cleaners participated in this study. While they performed their normal tasks, their oxygen consumption, heart rate, rating of perceived exertion and postural data were obtained. The perceived exertion during cleaning task using the "redesigned cleaning tool" was less than that of the "conventional cleaning tool". The oxygen consumption when cleaning with the redesigned tool (mean 0.841/m, SD +/- 0.17) was significantly less (p < 0.05) compared to the conventional cleaning tool (mean 0.941/m, SD +/- 0. 18). Heart rate was also found significantly lower using redesigned cleaning tool (mean 101 bpm, SD +/- 11. 10) compared to that of conventional cleaning tool (mean 105 bpm, SD +/- 12.59) (p < 0.05). Using redesigned cleaning tool the trunk postural load was also found significantly less than that of conventional cleaning tool (p < 0.05). It is concluded that redesigned cleaning tool allowed cleaners to maintain more upright posture when cleaning, which reduced biomechanical load. Relevance for Industry: There is need to develop ergonomic criteria or recommendation to enable manufacturers of cleaning equipment to specify and evaluate usability qualities when formulating user requirements for new cleaning tools.

The objective of this paper is to present a systematic review of the literature in the field to identify problems, recommended practices, unresolved issues and explore occupational needs related to cleaning problems. Selected for review were published and unpublished reports dealing with musculoskeletal disorders among cleaners. English language summaries of other language articles were also included. The factor mentioned most often is that cleaning is associated with high physical and psychosocial workloads. Recommended ergonomic interventions were summarized in a model to present a systematic overview, useful for research and practical applications. A few studies concern equipment design, working environments and factors affecting individual workers. A need to conduct research on cleaning tools/equipment, working environments and individual risk factors is apparent. Relevance to industry:Ergonomic strategies and methods are not widely practiced in the cleaning profession. If ergonomic principles can be integrated into existing cleaning industry tools, methods and work environments then efficiencies can be realized and the risk of occupational injuries will be reduced. The work efficiency and injury reduction will reduce employer-operating costs.

Administration entails a high level of computerization with multiple risk factors (including psychosocial and of ergonomic nature), affecting worker health and well-being. An ergonomics researcher supported by a senior ergonomist and guided by a domain specific checklist assessed physical ergonomics of an organization, including 96 administrative workers in the assessment. Unstructured observations and interviews to the workers were also done. Socio-demographic, musculoskeletal health and psychosocial job data was collected from a composite questionnaire including the versions validated for the Portuguese population of the Nordic Musculoskeletal Questionnaire (NMQ) and the Copenhagen Psychosocial Questionnaire (COPSOQ). This paper demonstrates an approach to jointly monitor multiple factors to support controlling work system efficiency, safeguarding health. Even though postural issues, especially static posture, have previously been identified as risk factors contributing to the onset of musculoskeletal disorders (MSD), the results of correlation analysis did not unveil a salient association between musculoskeletal complaints and ergonomic mismatches. The analysis did unveil statistically significant associations between exposure to psychosocial job factors and ergonomic risk factors. The pairs of variables actually associated were different according to gender confirming the need for future studies aiming the gendered study of MSD causality.

Relevance to industry: Computerized offices expose workers to multiple risk factors (including of psychosocial and ergonomic nature), and possibly influence their health and well-being. The paper demonstrates an approach to jointly monitor multiple factors to support controlling work system efficiency and negative outcomes.