| 1. |
- Kuster, Roman P, et al.
(författare)
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Active sitting with backrest support : is it feasible?
- 2018
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Ingår i: Ergonomics. - Stockholm : Karolinska Institutet, Dept of Neurobiology, Care Sciences and Society. - 0014-0139 .- 1366-5847.
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Tidskriftsartikel (refereegranskat)abstract
- Ergonomics science recommends office chairs that promote active sitting to reduce sitting related complaints. Since current office chairs do not fulfil this recommendation, a new chair was developed by inverting an existing dynamic chair principle. This study compares active sitting on the inverted chair during a simulated computer based office task to two existing dynamic office chairs (n=8). Upper body stability was analysed using Friedman ANOVA (p=.01). Additionally, participants completed a questionnaire to rate their comfort and activity after half a working day. The inverted chair allowed the participants to perform a substantial range of lateral spine flexion (11.5°) with the most stable upper body posture (≤11mm, ≤2°, p≤0.01). The results of this study suggest that the inverted chair supports active sitting with backrest support during computer based office work. However, according to comfort and activity ratings, results should be verified in a future field study with 24 participants.
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| 2. |
- Aasa, Ulrika, et al.
(författare)
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The effects of a 1-year physical exercise programme on development of fatigue during a simulated ambulance work task.
- 2008
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 51:8, s. 1179-94
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to evaluate the effects of individually prescribed physical exercise programmes on development of fatigue during the carrying of a loaded stretcher up and down the stairs. Nineteen ambulance personnel performed the training for 1 year. Testing occurred before and after 1 year of the training. Both the training group (n = 19) and the control group (n = 15) were assessed for physical capacity and lactate concentration in blood and ratings of perceived exertion during carrying a stretcher on the stairs. When comparisons were made between those who had been training three times/week for 1 year and the control group, lactate concentration was significantly decreased. In conclusion, markers of fatigue during stretcher carrying can be reduced by the use of individually prescribed physical exercise programmes.
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| 3. |
- Abeysekera, John D. A., et al.
(författare)
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Adaptation to discomfort in personal protective devices: an example with safety helmets
- 1990
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 33:2, s. 137-145
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Tidskriftsartikel (refereegranskat)abstract
- Discomfort in the use of personal protective devices (PPD) has been one of the chief causes of their non-use. A field trial using industrial helmets was carried out to ascertain whether by training and repeated wearing subjects could experience a significant adaptation to discomfort. Ten subjects took part in the trial in a tropical environment by wearing helmets repeatedly (6 h a day) for one month. Subjective evaluations of discomfort were made at the end of the 1st, 3rd, 5th, 14th and 30th day. It was revealed that complaints of discomfort, viz. hotness, heaviness, bad fit, etc., decreased markedly throughout the 30 day period. Though positive responses of adaptation to discomfort seem to reach an optimum towards 30 days, it is difficult to draw any conclusions on the optimum period of adaptation for each discomfort factor. In relation to inherent discomforts that are extremely difficult to overcome without compromising the protection efficiency of a PPD, the principle of adaptation seems to be a very important facet which has to be developed for an effective PPD programme.
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| 4. |
- Abeysekera, John D.A., et al.
(författare)
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Ergonomics evaluation of modified industrial helmets for use in tropical environments
- 1988
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 31:9, s. 1317-1329
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Tidskriftsartikel (refereegranskat)abstract
- Hotness, weight, fitting problems etc., have been found to be the chief causes of the unpopularity of industrial safety helmets in tropical environments in developing countries (DC). Some selected safety helmets manufactured in industrialized countries (IC) were modified to provide extra head ventilation and to reduce weight, in order to make them more acceptable to users in hot environments. The modified helmets were subjected to ergonomics evaluation both objectively and subjectively in the laboratory (in simulated tropical conditions) as well as in the field situation. There was evidence that white helmets had some advantages in comfort, viz. reduction of hotness, compared to the other colours, e.g. red, green etc., when worn in the presence of radiant heat in the laboratory. Ventilation holes provided at the top of the shell seemed to reduce the greenhouse effect within the helmet shell which therefore felt less uncomfortable than a fully covered helmet. Even with a small reduction of weight, such as 45 g in helmets weighing about 350g, the difference in weight was perceived by the wearers. In adapting helmets made in IC for use in tropical climates, head ventilation and low weight perception are important aspects in comfort which need to be considered. In addition to low cost, a harness material suitable for sweat absorption is required. Adjustability and sizing to fit 90% of the user population also needs to be considered in the design and manufacture of safety helmets for people in DC.
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| 5. |
- Adriansen, Arie, et al.
(författare)
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A socio-technical analysis of functional properties in a joint cognitive system: a case study in an aircraft cockpit
- 2019
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847.
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Tidskriftsartikel (refereegranskat)abstract
- In a socio-technical work domain, humans, device interfaces and artefacts all affect transformations of information flow. Such transformations, which may involve a change of auditory to visual information & vice versa or alter semantic approximations into spatial proximities from instruments readings, are generally not restricted to solely human cognition. This paper applies a joint cognitive system approach to explore a socio-technical system. A systems ergonomics perspective is achieved by applying a multi-layered division to transformations of information between, and within, human and technical agents. The approach uses the Functional Resonance Analysis Method (FRAM), but abandons the traditional boundary between medium and agent in favour of accepting aircraft systems and artefacts as agents, with their own functional properties and relationships. The joint cognitive system perspective in developing the FRAM model allows an understanding of the effects of task and information propagation, and eventual distributed criticalities, taking advantage of the functional properties of the system, as described in a case study related to the cockpit environment of a DC-9 aircraft.Practitioner Summary: This research presents the application of one systemic method to understand work systems and performance variability in relation to the transformation of information within a flight deck for a specific phase of flight. By using a joint cognitive systems approach both retrospective and prospective investigation of cockpit challenges will be better understood.
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| 6. |
- Ahlgren, Christina, et al.
(författare)
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Gender analysis of musculoskeletal disorders and emotional exhaustion : interactive effects from physical and psychosocial work exposures and engagement in domestic work
- 2012
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 55:2, s. 212-228
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to assess the relationships between physical and psychosocial work exposures, engagement in domestic work and work-home imbalance in relation to symptoms of musculoskeletal disorders and emotional exhaustion in white- and blue-collar men and women. Three thousand employees from 21 companies were asked to answer a questionnaire on family structure, household and child care tasks, work exposure, work-home imbalance and symptoms of neck/shoulder disorders, low back disorders and emotional exhaustion. Women reported more musculoskeletal disorders and engagement in domestic work. Adverse at-work exposures were highest in blue-collar women. High engagement in domestic work was not separately associated with symptoms but paid work exposure factors were associated. High engagement in domestic work interacted with adverse work exposure and increased risk estimates for low back disorders and emotional exhaustion. Reported work-home imbalance was associated with neck/shoulder disorders in women and with emotional exhaustion in both women and men. Practitioner Summary. The current article adds to earlier research by showing that high engagement in domestic work is not separately associated with increased symptoms, but interacts with psychosocial work exposure variables to produce emotional exhaustion in both women and men and low back disorders in women.
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| 7. |
- Antosz, Patrycja, et al.
(författare)
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Employee shirking and overworking : modelling the unintended consequences of work organisation
- 2020
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 63:8, s. 997-1009
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Tidskriftsartikel (refereegranskat)abstract
- Underworking (i.e. shirking) and overworking of employees can have detrimental effects for the individual and the organisation. We develop a computational model to investigate how work structure, specifically the way in which managers distribute work tasks amongst employees, impacts work intensity and working time. The model draws on theories from economics, psychology and management, and on empirical observations. The simulations show that when managers correctly estimate task difficulty, but undervalue the employee's competence, opportunities for shirking are provided due to longer deadlines. Similarly, if managers overvalue the employee's competence, they set tighter deadlines leading to overwork. If task difficulty is misjudged, initially only influence on employee working time is observed. However, it gradually generates competence misjudgements, indirectly impacting the employee's effort level. An interaction between competence misjudgement and task uncertainty slows the manager's ability to correctly estimate employee competence and prolongs initial competence misjudgements. The study highlights the importance of applying dynamic modelling methods, which allows for testing theory assumptions in silico, generating new hypotheses and offers a foundation for future research. Practitioner summary: A computational model was developed to investigate how the structure of work allocation influences opportunities for shirking and overworking by employees. The paper demonstrates how dynamic modelling can be used to explain workplace phenomena and develop new hypotheses for further research.
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| 8. |
- Arborelius, U P, et al.
(författare)
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The effects of armrests and high seat heights on lower-limb joint load and muscular activity during sitting and rising
- 1992
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Ingår i: Ergonomics. - : Taylor & Francis. - 0014-0139 .- 1366-5847. ; 35:11, s. 1377-1391
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Tidskriftsartikel (refereegranskat)abstract
- The loading moment of force on the hip, knee, and ankle joints of nine healthy men rising from four different types of stools were compared, together with the levels of myoelectrical activity (EMG) in four leg muscles. Two types of stool (stand stools) had higher seats than a normal chair. The other two were of ordinary seat height, but one also had armrests. The bodyweight carried by the different stools when sitting was also measured, and the subject estimated the effort required for each trial. The mean maximum knee moment was over 60% lower when rising from the high stool than from 'ordinary' seat height. The difference between the high and low stand stool was also significant (p less than 0.001). Using the high stool or help of the arms reduced the mean maximum hip moment by about 50%. The mean maximum ankle moment was only marginally influenced by the different stools. Knee moment was influenced more by seat height than was hip moment. Vastus lateralis activity was significantly higher when subjects rose from 'ordinary' height than when rising from either stand stool (p less than 0.001). The rectus femoris muscle was little activated and the semitendinosus muscle was activated earlier when rising from higher seat heights. All subjects estimated the effort of rising from the higher stand stool to be lower than from the lower stand stool or from 'ordinary' height without arm rests. It was concluded that stand stools are good alternatives for workers who change frequently between sitting and standing work.
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| 9. |
- Artman, Henrik
(författare)
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Situation Awareness and Co-operation within and between Hierarchical Units in Dynamic Decision Making
- 1999
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 42:11, s. 1404-1417
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Tidskriftsartikel (refereegranskat)abstract
- his paper is a follow-up of a field study of two military command teams and reports an experiment that tests three organizations (serial, parallel and optional) of co-operation and situation awareness within commander teams, as well as the communication between the commander team and the operative level. It was found that most groups in the optional condition performed worse than the groups in the other conditions. It was also found that members of teams in the parallel condition differed from members of teams in the serial condition in their situation awareness. The more successful commander team produced more planning in relation to hypothesis, as well as sending fewer messages in total between the units, than the less successful team.
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| 10. |
- Artman, Henrik
(författare)
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Team situation assessment and information distribution
- 2000
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 43:8, s. 1111-1128
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Tidskriftsartikel (refereegranskat)abstract
- Described is the cooperative work of constructing team situation awareness within two teams of a military command and control unit. Specifically discussed is how the distributed cognitive and cooperative work of decision-making of the two teams is structured. The situation enabled two different ways of distributing information within the team: one serial and one parallel. One team chose the parallel information transfer, the other the serial one. Discussed is the interaction patterns that emerge in the respective teams and their consequences for situation assessment and situation awareness. The differences are then discussed in terms of means of sharing information. Some hypotheses for future research are also offered.
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