| 1. |
- Bengtsson, Peter, et al.
(författare)
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Computer-Aided Planning of Production, Working and Residential Environments
- 1996
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 17:1, s. 59-68
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Abeysekera, John D.A., et al.
(författare)
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Body size variability between people in developed and developing countries and its impact on the use of imported goods
- 1989
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 4:2, s. 139-149
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Abeysekera, John D.A.
(författare)
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Ergonomics and technology transfer
- 1990
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 5:2, s. 181-184
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Abeysekera, John D.A., et al.
(författare)
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Ergonomics of technology transfer
- 1987
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 1:4, s. 265-272
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Tidskriftsartikel (refereegranskat)abstract
- 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
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| 5. |
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| 6. |
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| 7. |
- Abeysekera, John, et al.
(författare)
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The identification of factors in the systematic evaluation of slip prevention on icy surfaces
- 2001
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 28:5, s. 303-313
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
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| 9. |
- Bao, Shihan, et al.
(författare)
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Interactive effect of ergonomics and production engineering on shoulder-neck exposure — A case study of assembly work in China and Sweden
- 1997
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 20:1, s. 75-85
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 10. |
- Bergquist, Karin, et al.
(författare)
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Quality function deployment (QFD) - A means for developing usable products
- 1996
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 18:4, s. 269-275
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 11. |
- Burström, Lage, et al.
(författare)
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Mechanical impedance of the human hand-arm system
- 1989
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 3:3, s. 235-242
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 12. |
- Burström, Lage, et al.
(författare)
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The influence of shock-type vibrations on the absorption of mechanical energy in the hand and arm
- 1999
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 23:5, s. 585-594
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 13. |
- Christmansson, Marita, et al.
(författare)
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A case study of a principally new way of materials kitting—an evaluation of time consumption and physical workload
- 2002
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier. - 0169-8141 .- 1872-8219. ; 30:1, s. 49-65
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 14. |
- Engström, Tomas, 1950, et al.
(författare)
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Alternatives to Line Assembly: Some Swedish examples
- 1996
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Ingår i: International Journal of Industrial Ergonomics. - 1872-8219 .- 0169-8141. ; 17:3, s. 235-245
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, some criticism of Lean production has occurred, focusing among other things on the working conditions and the susceptibility of traditional assembly work in a society upgrading the demands for a more humanized work. Recently, this criticism has also concerned the technical aspects of this type of manufacturing. Because of this, alternatives to line assembly merit some attention. Experiences from some innovative production systems operated in the Swedish automotive industry during the last two decades are of particular interest. These unconventional production systems feature autonomous work groups and extended work cycles. These types of production systems are elucidated in detail by means of e.g nuance the concept of utilising buffers, i.e. there are different types of buffers (or buffer functions) as is classified (or clarified) in this publications.
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| 15. |
- Engström, Tomas, 1950, et al.
(författare)
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Data Collection and Analysis of Manual Work Using Video Recording and Personal Computer Techniques
- 1997
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Ingår i: International Journal of Industrial Ergonomics. - 1872-8219 .- 0169-8141. ; 19:4, s. 291-298
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Tidskriftsartikel (refereegranskat)abstract
- This publication initially reports on data collection and analysis of assembly systems including manual work using the so-called `loss analysis' which we have applied to the automotive industry during two decades of research and development work. In the further development of this method of analysis we have during the last few years synchronized a personal computer and a video recorder, thereby facilitating data collection of true shop floor information, as well as developing the analysis procedure to also include ergonomic aspects and work performance in the analysis. This publication reports on: (1) the background, (2) the prototype equipment used for data collection and analysis which is illustrated by empirical data using the equipment to analyze stamping of sheet metal, as well as assembly of automobile doors and drivelines, and (3) how to integrate a `loss analysis' with an ergonomic analysis of working postures (in this specific case using the so-called OWAS technique) studying assembly work on an automobile door. In this case, we noted that the division of labour loss represents over 60% of the time consumption for assembly work. This analysis indicates that from an ergonomic point of view it is primarily worth studying what activities are included in the assembly work classified as OWAS workload level 2. Relevance to industry This paper describes and illustrates methods and equipment developed consisting of a synchronized personal computer and video recorder. This promotes a design based on empirical data for specific cases through facilitating the collection and analysis of shop floor information about manual work and process efficiency of interest for the design of assembly systems.
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| 16. |
- Engström, Tomas, 1950, et al.
(författare)
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Empirical Evaluation of the Reformed Assembly Work at the Volvo Uddevalla Plant. Psychosocial effects and performance aspects
- 1995
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 16:16, s. 293-308
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the innovative, now defunct, Volvo Uddevalla final assembly plant. Theoretical frames of reference, the design process and empirical data on workgroup characteristics and working conditions are focused upon. Information regarding the Uddevalla plant has been gathered during a long-term co-operation project with the Volvo Corporation. During the closing-down period, we obtained full access to all the production engineering data and personnel files available. We also had the opportunity of studying the responses to a questionnaire distributed to a random sample of blue-collar workers. Working conditions in Uddevalla in the form of psychosocial job factors are compared with industrial blue-collar workers in general as well as with assembly workers in the closed down Volvo Kalmar final assembly plant, which had a different, more traditional, production system. The paper also compares the psychosocial job factors, performance measures and work-group characteristics in the five assembly workshops in the Uddevalla plant. In comparing assembly workshops, the paper contrasts two approaches to competence development and work structuring used in Uddevalla, namely (1) giving priority to the individual in-depth training of a specific task or (2) giving priority to a large competence overlap between individuals in a workgroup. Relevance to the industry. This paper reports and explains some results from a multidisciplinary evaluation of shop-floor work in the Volvo Uddevalla plant, a full-scale assembly plant with a parallelized flow and long cycle time, using autonomous work groups. These experiences should be of general interest to industries searching for the factory of the future.
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| 17. |
- Fernström, Elisabeth A.C., et al.
(författare)
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Alterations in shoulder muscle activity due to changes in data entry organisation
- 1999
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 23:3, s. 231-240
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Tidskriftsartikel (refereegranskat)abstract
- 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
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| 18. |
- Gao, Chuansi, et al.
(författare)
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The effect of footwear sole abrasion on the coefficient of friction on melting and hard ice
- 2003
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 31:5, s. 323-330
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 19. |
- Gellerstedt, Sten
(författare)
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Mechanised cleaning of young forest : The strain on the operator
- 1997
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 20:2, s. 137-143
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 20. |
- Geng, Qiuqing, et al.
(författare)
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Change in contact temperature of finger touching on cold surfaces
- 2001
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 27:6, s. 387-391
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 21. |
- Hammarskjöld, Eva, et al.
(författare)
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Effect of short-time vibration exposure on work movements with carpenters' hand tools
- 1991
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 8:2, s. 125-134
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 22. |
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| 23. |
- Johansson Hanse, Jan, 1954, et al.
(författare)
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Musculoskeletal Symptoms, Ergonomic Aspects and Psychosocial Factors in Two Different Truck Assembly Concepts
- 1993
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Ingår i: International Journal of Industrial Ergonomics. - 1872-8219 .- 0169-8141. ; 12:1-2, s. 35-48
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Tidskriftsartikel (refereegranskat)abstract
- The project was carried out as a multidisciplinary correlational study of two truck-axle assembly systems (System A and B). System A (the old system) could be characterized as an unpaced line assembly system, whereas the change to the new system, System B, involved a parallelized system with longer job cycle time. The study included all permanent assembly workers in the two systems (System A 17 workers, System B 28 workers). The purpose of this study was to evaluate the two systems with respect to ergonomic factors, psychosocial factors and self-reported musculoskeletal symptoms. The job cycles were studied by means of video observation. Each subject answered a questionnaire regarding musculoskeletal symptoms and physical and psychosocial environment. The assemblers in System B were more satisfied with the physical work environment (e.g. noise, air), but less satisfied with the psychosocial environment, and the period prevalence of musculoskeletal symptoms was not lower, compared with the assemblers in System A. Video observation techniques showed that deep forward flexion was less common, but that the work was more hand intense in System B. In System B, neck/shoulder symptoms were associated principally with physical work (load) variables, whereas low back symptoms were associated with psychosocial variables.
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| 24. |
- Karlqvist, Lena, et al.
(författare)
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Computer mouse and track-ball operation : Similarities and differences in posture, muscular load and perceived exertion
- 1999
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 23:3, s. 157-169
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 25. |
- Karlqvist, Lena, et al.
(författare)
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Self-reported working conditions of VDU operators and associations with musculoskeletal symptoms : a cross-sectional study focussing on gender differences
- 2002
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 30:4-5, s. 277-294
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 26. |
- Kuklane, Kalev, et al.
(författare)
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A field study in dairy farms : thermal condition of feet
- 2001
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Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 27:1, s. 367-373
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 27. |
- Kuklane, Kalev, et al.
(författare)
-
Thermal effects of steel toe caps in footgear
- 1999
-
Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 23:5-6, s. 431-438
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 28. |
- Liu, Xiaoxiong, et al.
(författare)
-
Subjective evaluation of three helmets in cold laboratory and warm field conditions
- 1999
-
Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 23:3, s. 223-230
-
Tidskriftsartikel (refereegranskat)abstract
- Helmets are widely used in industries as a primary protection means for workers. Helmets can provide efficient protection against occupational hazards to the head, they also cause thermal discomfort to the wearers at work. To develop a reliable heat transfer testing method for helmets any objective testing method must be validated with subjective testing of the same helmets. Subjective evaluation of helmet heat transfer properties was conducted in both cold and hot conditions using three commonly used and commercially available helmets. Twenty-five subjects participated in a laboratory investigation in a simulated cold environment( + 3 degrees C and 30% RH); forty-three steel-making workers participated in a held survey in the hot environment (31 degrees C and 32% RH). Subjects were either asked to conduct certain tasks (in the laboratory investigation) or performed their regular production duties (in the filed survey) while wearing a helmet; they were then asked to answer questions in a questionnaire at the end of the surveys. The results of the subjective assessment which were compared with the objective measurements taken on a sweating manikin head using the same helmets, were found consistent.
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| 29. |
- Medbo, Lars, 1957
(författare)
-
Assembly Work Execution and Materials Kit Functionality in Parallel Flow Assembly Systems
- 2003
-
Ingår i: International Journal of Industrial Ergonomics. - 1872-8219 .- 0169-8141. ; 31:4, s. 263-281
-
Tidskriftsartikel (refereegranskat)abstract
- This paper reports on materials kit functionality - usefulness of the materials kit in respect of operators' handling of materials and cognition during assembly work. That is, how the materials kit facilitates assembly work as well as promotes learning. This analysis comprises video recordings of nine automobiles in total from the closed down Volvo Uddevalla plant; a plant with parallel flow, long cycle time assembly work, where the materials supply was designed to facilitate the assembly work. To evaluate the usefulness of a materials kit from an assembly point of view, its configuration was related to the observed assembly work, and the level of structural congruence was estimated in order to judge to what extent the materials kit actually supported the assembly work. Briefly summarised, by using an analysis method in the form of 'signal component' methodology, this analysis showed that the assembly work proved to be almost identical when there were no technical differences between the layouts. It was thus assumed that it is possible to design materials kits in accordance with the observed assembly work, even though the materials kits configuration in the case study was not fully optimised and the stipulated work patterns were not in agreement with the observed work patterns. The ideal situation is that the operator picks components from one materials container at a time; however, it turned out that the operators picked from nearly two materials containers simultaneously. Relevance to industry Parallel flow, long cycle time assembly systems call for knowledge about conformity in the execution of assembly work within a work group. This paper reports on a case study focusing on the possibility to design common materials kits and assembly instructions, which in turn influences e.g. materials supply and learning times. © 2003 Elsevier Science B.V. All rights reserved.
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| 30. |
- Piamonte, D.P.T., et al.
(författare)
-
Understanding small graphical symbols : A cross-cultural study
- 2001
-
Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 27:6, s. 399-404
-
Tidskriftsartikel (refereegranskat)abstract
- Graphical symbols such as icons or pictograms as interfaces in modern technological devices have become quite common. Although generally designed in western countries, their use can be found worldwide from audio-visual appliances to computers and computer-related devices. A basic ergonomic principle is to involve the potential users in the design and evaluation stages especially when the user groups are quite diverse. This study was part of an international project on evaluating telecommunication symbols. One of the major objectives was to test different graphical symbols (of the videophone), designed, and tested in Western Europe using subject groups from Asia, Europe, and the United States. This paper would discuss the major portions of the tests involving US and Swedish subjects. Performance indices used were hits, certainties, confusions, and semantic differential ratings. They were useful in analysing how the symbols were recognised, confused, and perceived by different subject groups. They also helped detect differences between groups which otherwise seemed to have similar test results. The results showed differences in patterns of ratings, which may be culturally linked and could help determine aspects of symbol design and usage that may be more helpful in designing instructions, learning aids, etc. Awareness of such subject bias and their implications are important on how one interprets the test results.Relevance to industryThe study outcome can be very helpful for industries in designing and evaluating candidate graphical symbols across various types of consumer products for worldwide use. Copyright © 2001 Elsevier Science B.V.
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| 31. |
- Shahnavaz, Houshang
(författare)
-
Ergonomics : an emerging concept in industrially developing countries
- 1989
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 4:2, s. 91-100
-
Tidskriftsartikel (refereegranskat)abstract
- Industrialization via technology transfer is seen as the main development strategy by many developing countries (DC). The assumption that importation of advanced technology on its own, without adapting it to the environmental, physical, mental and sociocultural needs of the workforce in the receipient country would bring technical changes for the benefit of the majority of people has proved to be unrealistic. The failure to appreciate the characteristics and preferences of human operators has often frustrated technical development, alienated the work force and achieved little to improve the living and working conditions of the local people. Ergonomics is a useful tool for evaluating the choise of technology and its implementation and can contribute to the safe and productive transfer of technology. However, the area is fairly new or even unknown in many DC. They need assistance to acquire and apply the knowledge to their own need and capacity. It must also be emphasized that the available body of knowledge (e.g. standards, recommendations, procedures, etc.) concerning working conditions, occupational health and safety, which has been developed largely in industrialized countries (IC), often cannot be applied directly to DC, because of significant differences which are existing in all aspects of the work system between IC and DC. Since many factors influencing the nature, extent and diversity of problems are specific to each DC (e.g. climate, people, method of work, facilities, infrastructures of technology, finance, etc.) it is necessary to incorporate research into industrial development programmes.
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| 32. |
- Shahnavaz, Houshang, et al.
(författare)
-
Preface
- 1989
-
Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 4:2, s. 87-89
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 33. |
- Trapenskas, Donatas, et al.
(författare)
-
Localization performance of binaurally recorded sounds with and without training
- 2001
-
Ingår i: International Journal of Industrial Ergonomics. - 0169-8141 .- 1872-8219. ; 27:6, s. 405-410
-
Tidskriftsartikel (refereegranskat)abstract
- One of the problems associated with listening to binaurally recorded sound events is localization confusions. The main objective of this investigation was to find out whether a short training session prior to listening to binaural recordings through headphones would facilitate correct spatial perception of the sound field. Focus was on the localization of the sound stimuli in median plane. Sound signals were recorded with an artificial head in three different conditions namely, anechoic, highly reverberant and moderately reverberant. Fourteen subjects participated in the listening tests. All subjects were required to localize all virtual sound stimuli under two different conditions. The first condition had a short training session binaurally recorded in the same environments as preceeding sound stimuli, and only sound stimuli recorded in the same environment were presented. The second condition did not have a training session, and sound stimuli recorded in different environments were presented. Results showed that a short training session prior to listening to binaurally recorded sounds through headphones was useful as it facilitated localization performance. The biggest effect was in reduced amount of sounds perceived inside the head. It was most pronounced for sound stimuli recorded in anechoic environment.
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| 34. |
- Wos, Henryk, et al.
(författare)
-
Perceptual rating of local vibration : A psychophysical study of hand-arm vibration of short duration (Part I)
- 1988
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 2:2, s. 143-150
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to try to determine a stimulus-response relationship for sinusoidal hand-vibrations rated on Borg's scale. A frequency range of 30-200 Hz, covering commonly used hand-held tools, was studied.The need for perceptual measurements is great, inter alia, in connection with ergonomic analyses of real work situations. The possibility of using sophisticated measuring equipment at the work place is sharply limited. Consequently, the self-rating method may constitute a practical means of assessing the complex vibrational intensities. The subjective perceptual rating takes account of other individual factors that are difficult to measure objectively, e.g. work technique and occupational experience.The study shows that self-rating based on Borg's scale can be used to assess vibrational intensity. The perception of increases in the amplitude of vibrations at a certain frequency is progressive. We find a significant rating pattern with a power function that expresses the stimulus-response relationship.
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| 35. |
- af Wåhlberg, Anders E.
(författare)
-
Long-term effects of training in economical driving : Fuel consumption, accidents, driver acceleration behavior and technical feedback
- 2007
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 37:4, s. 333-343
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 36. |
- Arvidsson, Inger, et al.
(författare)
-
Changes in physical workload with implementation of mouse-based information technology in air traffic control
- 2006
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 36:7, s. 613-622
-
Tidskriftsartikel (refereegranskat)abstract
- Effects on physical workload were quantified when introducing new information technology in air traffic control. Seven female and 7 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; elect romyography 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 degrees/s, P < 0.01; right arm elevation: 3 vs. 6 degrees/s; P < 0.01; [90th percentile] wrist flexion: 19 vs. 50 degrees/s, P < 0.01), less varying postures (head: 95th-5th percentile range 17 degrees vs. 34 degrees; 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. (c) 2006 Elsevier B.V. All rights reserved.
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| 37. |
- Balogh, Istvan, et al.
(författare)
-
Increasing the Degree of Automation in a Production System: Consequences for the physical workload
- 2006
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 36:4, s. 353 - 365
-
Tidskriftsartikel (refereegranskat)abstract
- In spite of the continuous development of production systems work-related musculoskeletal disorders is still a large problem. One reason might be the difficulties in quantifying the ergonomic effects of interventions. In this paper ergonomic consequences of technical and organisational changes were quantified in a plant for producing slats for parquet flooring. Muscle activity, work postures and movements were assessed for neck/shoulders and upper limb by direct technical measurements at three generations of production lines. The physical workload for 31 operators at the manual, semi-automated and automated line was derived based on all existing work tasks. The work was characterised by moderate muscular loads, the 50th percentiles being 1.2-3.8%MVE for the neck/shoulder muscles, high repetitiveness and constant movements of the hands and a high prevalence of neck/shoulder disorders. There were statistically significant differences considering exposure levels between the work tasks within each line as well as between the lines. The semi-automated line implied reduced muscular load for all muscles registered but more constrained work postures. The automated line, on the other hand, required higher skills, offered less constrained postures, lower loads and repetitiveness for the hands as well as frequent changes between different physical load levels. Relevance to industry: When designing or redesigning production systems, technical solutions are often used to obtain 'beneficial' ergonomic conditions, implying a strive for low physical workloads. However, there is a risk that this might lead to more constrained physical activities. Possibilities for job enlargement must be thoroughly utilised. © 2006 Elsevier B.V. All rights reserved.
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| 38. |
- Berlin, Cecilia, 1981, et al.
(författare)
-
Corporate-internal vs. national standard - A comparison study of two ergonomics evaluation procedures used in automotive manufacturing
- 2009
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 39:6, s. 940-946
-
Tidskriftsartikel (refereegranskat)abstract
- 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. (C) 2009 Elsevier B.V. All rights reserved.
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| 39. |
- Bligård, Lars-Ola, 1976, et al.
(författare)
-
Predictive use error analysis – Development of AEA, SHERPA and PHEA to better predict, identify and present use errors
- 2014
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 44:1, s. 153-170
-
Tidskriftsartikel (refereegranskat)abstract
- In health care, the use of technical equipment plays an integral part. To achieve a high level of patient safety, it is important to avoid use errors when handling equipment. Use errors can be mitigated by performing analyses of potential use errors during the design process. One proactive analytical method for use error analysis is Predictive Use Error Analysis (PUEA), which is a further development of the methods Action Error Analysis (AEA), Systematic Human Error Reduction and Prediction Approach (SHERPA) and Predictive Human Error Analysis (PHEA). PUEA employs a detailed process for breaking down the user's tasks into steps and then identifying and investigating potential errors of use for each step. Compared with other methods, it is significant in its use of two question levels, greater inclusion of human cognition theory and that the results of the analysis are presented in matrixes. Relevance to industry: The PUEA method is useful to the industry for evaluating existing products or serving as an evaluation tool during the design process. For instance, the PUEA method has been used to evaluate user interface designs of home-care ventilators and dialysis machines. In addition, PUEA can be applied as a final risk assessment method assessment method in the product development process.
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| 40. |
- Bligård, Lars-Ola, 1976, et al.
(författare)
-
The power of the dollhouse : Comparing the use of full-scale, 1:16-scale and virtual 3D-models for user evaluation of workstation design
- 2018
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier. - 0169-8141 .- 1872-8219. ; 68, s. 344-354
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 41. |
- Bodin, Theo, et al.
(författare)
-
Activity in neck-shoulder and lower arm muscles during computer and smartphone work
- 2019
-
Ingår i: International Journal of Industrial Ergonomics. - : ELSEVIER. - 0169-8141 .- 1872-8219. ; 74
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 42. |
- Brolin, Erik, et al.
(författare)
-
Adaptive regression model for synthesizing anthropometric population data
- 2017
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier. - 0169-8141 .- 1872-8219. ; 59, s. 46-53
-
Tidskriftsartikel (refereegranskat)abstract
- 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 industryWhen 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.
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| 43. |
- Crenshaw, Albert G., et al.
(författare)
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Finger flexor contractile properties and hemodynamics following a sustained submaximal contraction : A study using electrical stimulation and near-infrared spectroscopy
- 2010
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 40:2, s. 153-160
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 44. |
- Falck, Ann-Christine, 1949, et al.
(författare)
-
A model for calculation of the costs of poor assembly ergonomics
- 2014
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 44:2014, s. 140-147
-
Tidskriftsartikel (refereegranskat)abstract
- In product development there are many design requirements to meet and often tough project budgets to keep. Requirements that are considered not profitable will often be neglected, which affects assembly ergonomics. The objective of this study was to develop a calculation model for application in practice that enables calculation of costs of poor assembly quality related to assembly ergonomic conditions. The model is meant to be used by engineers and stakeholders in the design or redesign of manual assembly solutions. For that purpose, manual assembly tasks of 47061 cars at high, moderate and low physical load levels were analyzed with respect to assembly-related quality errors and corresponding action costs during production and on the market. The results showed that ergonomics high risk issues had 5-8 times as many quality errors as low risk issues and the earlier these were found the less were the action costs. The action costs for errors that were discovered late in assembly were 9.2 times more costly compared to early repair of errors in the factory. The action costs for quality errors that were found and corrected on the market were further 12.2 times more expensive to correct compared to actions taken in the factory. Examples are shown of how to apply the calculation model that was developed based on the obtained quality data. Relevance to industry: Both ergonomics and quality issues can be proactively solved through simultaneous risk assessment in early product development and hereby late reactive action costs can be greatly reduced.
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| 45. |
- Falck, Ann-Christine, 1949, et al.
(författare)
-
Assembly failures and action cost in relation to complexity level and assembly ergonomics in manual assembly (part 2)
- 2014
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 44:2014, s. 455-459
-
Tidskriftsartikel (refereegranskat)abstract
- Earlier studies have demonstrated strong relationships between manual assembly at high physical loadlevels and increased amounts of quality defects compared to assembly at low physical load levels. Arecent Swedish interview study of engineers in design and manufacturing engineering indicated thatassembly complexity factors are of additional importance for the assembly quality. The objective of thisstudy was therefore to examine the significance of high and low complexity criteria and the relationshipsbetween assembly ergonomics and assembly complexity and quality failures by analyzing manual assemblytasks in car manufacturing. In total, 47 000 cars were analyzed and the results showed severalsignificant correlations between assembly ergonomics and assembly complexity, assembly time, failuresand action costs. The action costs for high complexity tasks were 22.4 times increased per task per carcompared to low complexity tasks.Relevance to industry: Assembly ergonomics and assembly complexity factors interact. Both should beproactively considered in order to keep assembly-related failures and action costs as low as possible.
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| 46. |
- Falck, Ann-Christine, 1949, et al.
(författare)
-
Basic complexity criteria and their impact on manual assembly quality in actual production
- 2017
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 58, s. 117-128
-
Tidskriftsartikel (refereegranskat)abstract
- Increasing design and assembly complexity are challenges facing the automotive industry today because increasing number of car variants and build options can result in immense difficulties and lead to costly assembly errors and quality losses. In order to remain on the market these conditions must nevertheless be managed by companies in hard competition with other manufacturers. The objective of this study was to analyze the impact of newly developed basic complexity criteria (CXB) on assembly quality and associated costs for corrective measures in manual assembly of cars. Data on error rate and action costs of assembly tasks of different complexity level was collected and analyzed. The inter-relationship between different complexity criteria was analyzed to see whether any criteria had a greater impact than others. The results showed that the action costs/car increased with increasing complexity level and that several complexity criteria together resulted in increased action costs. Some criteria tended to have a greater impact than others but need more research. The results further suggest that if high complexity issues are identified and replaced by low complexity solutions the assembly related action costs in manual assembly are likely to decrease.Relevance to Industry: By reduction of basic assembly complexity already in early planning stages in product development significant reduction of costly assembly related action costs in manual assembly can probably be made.
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| 47. |
- Falck, Ann-Christine, 1949, et al.
(författare)
-
What are the obstacles and needs of proactive ergonomics measures at early product development stages? - An interview study in five Swedish companies.
- 2012
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 1872-8219 .- 0169-8141. ; 42:5, s. 406-415
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Tidskriftsartikel (refereegranskat)abstract
- Despite health and safety legislation and ergonomics regulations for several years many Swedish companies are still unable to effectively prevent the consequences of poor ergonomics. Corrective measures are often made (too) late when employees complain and work-related disorders have already occurred. Besides, several studies have shown that poor ergonomics result in deteriorated assembly quality and reduced productivity and that late measures are often costly. Other studies have proven that design engineers are often unaware of design consequences and do not know how to apply ergonomics principles in new product and production design. Therefore, the purpose of this study was explore what is required to improve the situation. One way to find out was to ask engineers involved in product and production development. Thus, 64 engineers in design and manufacturing engineering in five Swedish companies were interviewed about ergonomics conditions related to quality and productivity issues. In general, their answers unexpectedly demonstrated a fairly good awareness of the implications of poor assembly ergonomics but also that appropriate product and production design methods and tools to prevent these are missing. 58 of the respondents thought that poor ergonomics can result in reduced product quality. 47 stated that profitability calculations are necessary for changes of poor ergonomic solutions. 37 said that ergonomics risks are accepted due to lack of appropriate calculation methods. Altogether, many suggestions emerged for how to improve product and production design methods and tools in order to achieve more complete and sustainable manufacturing solutions.
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- Glimne, Susanne, 1966-, et al.
(författare)
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Eye symptoms and reading abilities of computer users subjected to visually impaired direct glare
- 2019
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier. - 0169-8141 .- 1872-8219. ; 72, s. 173-179
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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