Tag Archives: Health of Ageing Staff

by Ivo Tokarski, 2011.

This paper synthesizes secondary and empirical research findings on the ageing workforce into a hypothetical research, focusing on the interdependency of increasing health of ageing staff on the success of implementing a job rotation strategy in the assembly line in the manufacturing sector. This paper will focus on a literature review of peer-reviewed articles, completed through own interpretations. The goal of this paper is to find conclusions for management, about the ever more important issue of ageing workforce, and give findings for future implications of a job rotation strategy in the assembly line.

Keywords: Ageing Workforce; Job Rotation Strategy; Health Of Ageing Staff; Assembly Line; Literature review.

1. Introduction
The increase of the world population, as well as the ever-increasing average age each person reaches is shown in several studies (see, for example, European Foundation for the Improvement of Living and Working Conditions, 2003). Longer life expectancy is especially evident in many developed countries mainly due to differences resulting from the quality and access to health services, lower birth rates and economic prosperity. If we look at the United States for example in the year 2006, approximately over 37 million citizens were aged over 65, which makes a 12,5 percent share of the total population. According to the article of Schlick (2010), this number is likely to grow to about 72 million by the year 2030, which makes a 19,3 percent share of the total population. This demographic change, which results through the ageing population, is also having an impact in the European Union (EU). The proportion of the working population between the ages of 55 and 64 is expected to increase from 56 million in 2006 (11.4 percent of the total population) to 70 million in 2030 (13.5 percent). Furthermore, the number of people in the EU aged 65 and older is expected to increase from 82 million in 2006 (16.8 percent) to 122 million in 2030, which equals an increase from 16,8 percent in 2006 to 23,5 percent of the total population in 2030 (Schlick, 2010).
The topic of ageing populations has also a natural impact on the issue of ageing workforce. The changes of demographics affected by the shrinking working-age population for instance, lead Germany to change the age of receiving the full social security retirement benefits from 65 to 67 (Thun et al., 2007). This proves that ageing workforce has a significant economic impact, but literature shows (Raina et al., 2001), that the issue of this topic is far more complex because of the fact that as people age it includes variables like perceptual, cognitive and motor systems which can have significant effects on their performance in work-systems (Schlick, 2010). This questions whether the German approach is the right one and to which level overall fitness and health is playing a role in the performance of ageing workforce.
In this research paper I will narrow this topic down and investigate to which extent health of ageing staff is influencing the successful implementation of a job rotation strategy in the assembly line. This hypothetical research will show if and how strong the variable of health influences the success of implementing a job rotation strategy in the scope of an assembly line.
Chapter 2 will give a more detailed view on the intention and research gap, which will lead into a literature review in chapter 3, a resulting conceptual model of influencing factors in chapter 4, completed by the methodology and findings in chapter 5 and 6.

2. Research question and research gap
Many empirical studies have been conducted to evaluate the influence of ageing workforce on the overall productivity in companies. In this research the focus shall be laid on the health factor of ageing staff and to what extent it increases the successful implementation of a job rotation strategy in the assembly line. If a given company knows the result of this research, it will provide the possibility to invest in preventive measures to increase the health of ageing staff, being it through training, health care or the improvement of ergonomics in the company, given that the research will show a significant correlation between the level of health and the successful implementation of a job rotation strategy. The goal of this research is to show that due to the increasing pool of ageing workforce, companies in the manufacturing sector can increase their efficiency and therefore reduce their production costs by implementing a job rotation strategy, which will also allow them to use the ageing staff in a flexible manner. Staff will deal with different production areas, which should stimulate their motivation and prevent singular working load in their job, which could have a positive influence on the level of health due to reduced physical stress resulting through manual routines in the assembly line process.
This research will supply the needed answer to the question if investment in preventive measures to increase the health level of ageing staff is a factor, which influences the implementation of a job rotation strategy in the assembly line positively.
In the progress of this research following sub questions shall be also addressed:
• To what extent does an increased level of health contribute to an increased productivity in the assembly line?
• To what extent can innovations in assembly lines increase productivity?

2.1 Definition of terms
Because I will use several terms excessively, I would like to explain them briefly in order to create a common understanding of what is meant by them. I will excerpt the most important terms and explain the definition briefly in this section.
The level of health of ageing staff – is the overall condition of the ageing staff, which is determined by physical, motoric, sensoric or/and cognitive conditions. In this research I assume that a healthy person can be distinguished by not having any of those conditions to a degree which is limiting them in their working environment, being it through limitation to perform certain tasks because of physical predispositions like e.g. back pain vs. heavy lifting. The level of health can be theoretically measured in percents relative to the possible abilities of performing a task. 100 percent means the highest level of health determined by work freedom, then scaling downwards to zero percent determines the level of “unhealthy” staff, which are restricted by some conditions to perform certain tasks.
Job rotation strategy – “Job rotation is defined as lateral transfer of workers among a number of different workstations where each requires different skills and responsibilities. […] As a benefit to firms, job rotation is said to improve a firm’s ability to deal with change. Flexible workers can provide buffer against uncertainties in manufacturing systems (Kher et al., 1999).”
Successful implementation of job rotation strategy in the production line – A successful implementation of this strategy is determined by whether it results in an increased efficiency at the assembly line, after the strategy has been implemented. This can be theoretically measured by comparing assembly times and output prior to the job rotation scheme, to the assembly times and output after implementation.

3. Literature review
3.1 The ageing workforce and health issues
As the author Arnone (2006) puts it:
“An ageing society faces many challenges that involve a broad range of economic, social, political and cultural issues. One aspect is the impact of an ageing workforce on a nation’s productivity, economic growth and global competitiveness. The deployment and contributions of older workers affect not only the economic and social well-being of the workers themselves, but also the standard of living enjoyed by current and future generations.”
Because the trend of increasing age of workforce is prospering in many countries, it can be argued that the impact on the economy will continue for years to come. The concern that the ageing workforce brings with them some associated impairments regarding work capacity and productivity seems to feed concerns in the industry. The age-related impairments can be found in several cognitive abilities, which can suffer. The authors Sülzenbrück et al. (2010) give a good overview of functions in which age-related impairments have a negative effect on working capacity and productivity. Their classification shows not only cognitive but also physical/ motoric impairments. The impairments can be divided into:
„Divided attention, sustained attention over long time spans and selective attention, further visuospatial attention, auditory attention, working memory, and inhibition. Also motor abilities suffer from an age-related decline. Loss of muscular strength, endurance and tone have been associated with aging making the execution of physically demanding jobs more difficult at older age (Sülzenbrück et al., 2010).“
So what does that mean in connection to the variable of increased health of ageing staff with respect to the successful implementation of a job rotation in the assembly line? Well, according to the results of Sülzenbrück et al. (2010) research, the generalized slowing of aged workforce and the therefore resulting impairments do not generalize across all types of motoric skills. In their empirical research they have shown that older participants even though they scored slower in cognitive speed, they scored significantly higher in motoric accuracy and speed testing than younger participants.
These findings are especially interesting for this research because they prove that there is a competitive advantage of aged staff in comparison to young staff. Aged staff is able to compete with younger ones by their experience and knowledge, which the results of the above-mentioned research showed in a faster motoric speed that can be related to experience and a higher motoric accuracy that can be related to both, experience, and knowledge. That is why I want to investigate if these motoric abilities can be even more increased through a higher level of health, which hypothetically could result in an overall motoric improvement and therefore contribute to the increase of efficiency and productivity within aged staff. The job rotation strategy will give an additional factor of keeping the level of workload diffused so that any action towards increasing the health and fitness of the aging staff will not be dimished. The assembly line will narrow the scope of the research because it is the smallest possible researchable application sector.
The report from Bupa “The Healthy Work: Evidence into Action”, mentioned in the article of Paton (2010) goes a step further and argues that the trends in demographic changes will mean that workers in the future generally will be sicker and older. The report does not see the health of ageing staff as an opportunity for increasing productivity but rather argues that there will arise a big threat to management of decreasing productivity by having to concentrate on managing absence, attendance and promoting workplace health because of the chronic health conditions, like e.g. obesity, of their staff. The report, which was taken in the UK, estimates that about 40% of adults will set to be obese by 2025.
In my opinion introducing preventive measures in increasing the level of health can hinder this scenario and turn this evident threat into an opportunity.

Productivity, performance, innovation and aged staff
The perception of aging staff is changing throughout the last years, because of the economic impact this demographic group gains. The worldwide development of the economy to a knowledge based economy brings a large amount of complementary needs with it, which can be supplied by the constant development of new technologies that help the aged workforce to be able to extend their working lives without sacrifice of health (Arnone, 2006).
Complementary to this there is the economy shift to supply better fitted services to the ageing workforce, e.g. health insurances coverage and better medical care, which support the productivity increase in the economy by increasing the mental and physical well-being of the aged workforce (Arnone, 2006).
Companies in the industry have realized the chance and benefits that an aged workforce can bring with them. Not only the knowledge base can be increased but also a primary contributor could be the diversification of labour force, where aged staff can create a synergy effect on young employees by functioning as a mentor. Increasingly interesting for firms could be a model in which the education costs can be lowered by assigning an aged staff member to a group of younger ones, who constantly can teach and supervise his teammates. This win-win situation can not only reduce education costs on one side but contributes also to counteract the diffusion of knowledge, because a one time education will not be that good memorized like constant repetition with the guidance of a mentor. Another positive factor could be that if the aged staff member teaches the younger ones, he is able to delegate more of his tasks, and therefore will not be that much physically exhausted like he would have been when performing all of the tasks assigned to his position by himself.
Those implications are especially important in the lean production systems in which the assembly lines play a crucial role in the speed of processing that is highly vulnerable to interruptions. Without buffering the stock and creating a balanced assembly line, the production rate will be only constant until a problem is detected and as a result the whole line will stop (Allwood & Lee, 2004). So from the management perspective it is a key success factor of exploring the problem solving in the lean production systems. One way of responding to the increasing need of operator problem solving skills therefore is the job rotation scheme, which increases the efficiency of operators who are facing repeating tasks that influence positively on their learning-curve (Allwood & Lee, 2004). The positive effect of job rotation schemes is researched by Allwood & Lee (2004) extensively and their results show that “the run-ratio generally increases as operators learn more rapidly and forget more slowly, and decreases as the number of problems increase.” This shows that a job rotation strategy avoids any possible advantage in specialization on certain problems, which do not occur uniformly at all workstations. The interesting part for my research is that Allwood & Lee (2004), did not divide their research groups by age, which could be interpreted in the way that the general result of advantage through the learning curve and the therefore resulting “allround-problem-solvers” is not age related, ergo: Organisations and management will also benefit from ageing staff.
What implications are then important for the performance part, in other words: How can management create incentives to increase performance of ageing staff?
Job rotation is widely used and recommended as an administrative control to the risk of developing work-related musculoskeletal disorder (Frazer et al., 2003), or more generally speaking the decreasing physical health. This is also the tag that I am using while defining the influencing variables, which have an influence on the factor of the successful implementation of the job rotation strategy. I suggest that an increased level of health in the aging staff will influence the success of the strategy, in the way that it will enhance efficiency, productivity, flexibility and foster innovation through the continuous improvement process (Freiboth in Frazer et al., 2003).
Nevertheless, this view is not supported by all researches. Keyserling et al. (1991) indicated that job rotation “by itself only changes the cumulative daily exposure but does not alter other generic risk factors (e.g. awkward postures, repetition) to which a worker is exposed. While a job rotation strategy might evenly distribute cumulative loading, raising it for some workers, lowering it for others, it also exposes all workers involved in the rotation schedule to the highest peak load, increasing the predicted risk for everyone rotating.”
Keyserling et al. (1991) have made a good point but nevertheless the probability seems less likely that a shorter exposure to e.g. awkward postures has a lower impact on the physical health than the exposure of only a part of the staff to perform those tasks, which recommend awkward postures. The main problem stays the same – the awkward postures remain while Keyserling et al. (1991) prefer to choose certain people who do not have health issues and implicitly increase their probability of developing health issues, rather than expose the staff who already have a lower level of health. I see two problems with that: Firstly, like I have mentioned in the introduction, the number of ageing workforce increases and there is no sign that this trend will change, therefore management will have problems with implementing Keyserling et al. (1991) theories in some time, simply because there will not be enough workforce with an high level of health because a big proportion will be aged by then and will have age related health issues. Secondly, this theory suppresses the knowledge exchange and therefore innovativeness within the company because there will be an informal selection of workforce which not only will discriminate a certain part of the staff (mainly the aged staff), but will engage a closed mentality (“we against them – syndrom”). This could result in specialization on a specific task in the assembly line, which will decrease flexibility because the worker cannot swiftly replace another one, which further can enhance the lack of communication that could result in inertia.
Aged staff take an important part in future decisions for management. Especially innovations like the increased replacement of human workforce by automatisation will have an effect on aged workers, because of the increased knowledge and technology load they have to process in an innovation-driven economy (Streb et al. 2009).
But there is the chance of aged staff to take advantage of these economic trends. When we take the classification of innovations by Jacobs (2007), we can divide them into product innovation, process innovation and transaction innovation. The innovations, which the aged staff will increasingly have to deal with, are the process innovations because of the automatisation process, they will have to work on the assembly line with robots and automatic tools. If we take a look at the job rotation strategy now, we can see that this is also a kind of process innovation because it uses a new distribution of tasks which result in an added value for the company (e.g. less fluctuation of staff) as well as for the worker (e.g. less health issues). Furthermore, the job rotation at the assembly line will increase communication, problem solving and can be used to extract knowledge of young as well as aged staff in order to make work processes or tasks more efficient. Therefore it can be argued that the implementation of the job rotation strategy could result also in an increased innovativeness through an open innovation approach within the company and in the end result in a competitive advantage due to increased efficiency in the assembly line.

4. Conceptual model and hypothesis
In this chapter I will give the graphical illustration of the conceptual model, illustrating how and which factors do influence the successful implementation of the job rotation strategy and further state the relevant research hypothesis.
During the literature review I have noticed the repeated usage of describing factors which where connected to aged staff and health issues. Because the issue of health in ageing workforce is so dominant in the literature I have reviewed, I have decided to make it my main factor, which is influencing the successful implementation of a job rotation strategy in the assembly line. This factor is very complex by itself and in respect to the influence of other variables. In this research the level of health should be seen as a generalized term which includes the overall condition of the ageing staff, which is determined by physical, motoric, sensoric or/and cognitive conditions, as stated in the definition of terms (see chapter 1).
Because the level of health brings with it a chain reaction it is at the left hand side of the conceptual model (see Figure 1). In my argumentation the level of health influences the performance of aged staff in the assembly line due to an increased ability of performing tasks. The authors Cropanzano et al. (2003), mentioned in the article of Streb et al. (2008), would not be convinced by my personal interpretation because they argue that as a criterion for job performance, emotional exhaustion goes beyond factors such as age. I want to point out that they are concentrating on the cognitive and more or less sensoric side of exhaustion and I am taking also physical and motoric factors into consideration.
Further, the performance affects the productivity because it increases the output through increased input of aged staff, like the authors Azizi et al. (2009) mention, that manufacturing productivity is affected by both the human and machine factors, because in the end the human operates the machine.
Productivity on the other hand is contributing to the learning curve and to the increase of knowledge because when the output increases through a higher productivity, the staff has a more intensive link to the tasks, machines and processes they have to maintain. The increased knowledge gained through the increased productivity could result in an open innovation approach at the assembly line, which could contribute towards efficiency improvement. If the efficiency can be increased – the overall workload for aged staff could decrease because of the job rotation strategy. If the overall process initiated through the increased level of health could have a “dripple-down” effect on those other factors, the implementation of the job rotation strategy will be successful.

Figure 1 – Conceptual model

Resulting from my evaluation, I therefore want to research following hypotheses:
H0: ihas = sjrs ; (increased health of ageing staff has a positive effect on the successful implementation of the job rotation strategy)
H1: ihas ≠ sjrs ; (increased health of ageing staff has not a positive effect on the successful implementation of the job rotation strategy)
By researching these hypotheses I will be able to distinguish to what extent the increased level of health within aged staff will increase the successful implementation of a job rotation strategy in the assembly line.

5. Methodology
In this research qualitative, as well as quantitative data is needed in order to supply a valuable conclusion. The main implications for this empirical research will be important for management decisions in the manufacturing sector, where assembly lines are used in. The main industries where assembly lines play a crucial role in the overall production are especially the automotive and electro technique industries where complex products are being mounted together in many steps.
Several companies could be taken into consideration for the scope of this research. To prevent on focusing only on the automotive industry on which most studies concentrate (Streb et al., 2009; Weichel et al., 2010) when researching the effects of job rotation I shall also include different sectors in the manufacturing industry like the high-tech electronic goods assembly lines. Because of the different sectors the factors will concentrate on the level of health of the staff, especially the aged staff, which can be compared with other companies.
To draw a bigger scope of comparison companies like Daimler-Benz, Volkswagen, Fiat, Ford, General Motors, and Toyota could be compared together with high-tech companies like Bosch, Siemens, Whirlpool, Electrolux, Samsung and Sony. This will give a global insight on trends in the assembly lines, where job rotation can be implemented and has the possibility to increase competitiveness through a better “exploitation” of aged staff. The comparison between the matured automobile sector where job rotation is already used in many processes, and the high-tech sector can show if there is a relationship in an increased level of health of ageing staff and a successful implementation of a job rotation strategy or not. Comparing two different market sectors will give insight if this variable is significant or not, and will give information if the hypothesis can be rejected or not.
Firstly, in order to gather the needed information about the companies I suggest performing a qualitative research by sending questionnaires to the companies regarding the measureable factors I want to investigate. Those questionnaires would be designed to answer current, past and predicted trends of demographic changes regarding the ageing of staff and the impaired developments affected by that. The factors will be those ones mentioned in the conceptual model, namely the increased level of health, performance, productivity, knowledge, innovativeness and workload.
Secondly, quantitative research will be performed by collecting data from the emission prospects of the mentioned companies and available scientific literature concerning the topics of job rotation strategy and ageing workforce. This second stage will show if there are similarities of performance, productivity, knowledge, innovativeness and workload when comparing the results of the qualitative research with the overall trends and challenges businesses’ globally have to deal with. The next step is to research if those factors can be generalized to the main hypothesis that if the level of health would increase it will have a positive effect on the implementation of the job rotation strategy. If the comparison of qualitative and general quantitative data will show a significant correlation, the result could be translated into the assumption that the challenge of increasing efficiency for companies when dealing with ageing staff can be positively influenced by increasing the level of overall health, which will positively influence the successful implementation of a job rotation strategy and therefore increase efficiency in manufacturing processes.

6. Expected Findings
With the outcome of this study I expect to have gathered valuable information that could help to influence future management decisions which have to deal with the challenge of managing ageing staff. These findings should give insight if it makes sense for management to invest in health increasing matters for their ageing staff, for example – training, improving ergonomics, workouts, physiotherapy, massages, etc. (Landsbergis, 2007), in order to gain efficiency improvements in the manufacturing process.
Figure 2 shows the expected influence each of the factors has on the successful implementation of a job rotation strategy.

Figure 2 – Conceptual model of expected findings

I expect that an increased level of health has a positive effect on performance, hence performance increases. Performance has a positive effect on productivity because an increased performance level should result in an increased productivity. Through an increased productivity the output of the assembly line is being increased, therefore also the amount of task-handling increases, hence the knowledge increases because staff is exposed to a higher product flow. The increased knowledge on the other hand has a positive effect on innovativeness because it can contribute to problem solving skills, inventiveness and synergy effects (Allwood et al., 2004). The therefore increasing level of innovativeness has a countercyclical effect on workload, because innovativeness can enhance process optimalisation, which will result in the decrease of workload and increase of efficiency.
All those factors combined influence the success of implementing a job rotation strategy in the same way as they are interrelated. Workload is the only factor, which is having a negative, or moderate influence on this. If workload is reduced because of the interrelation-effects to the other factors, management can question whether the job rotation strategy is still needed and if the main purpose of increasing efficiency in the manufacturing process at the assembly line, is not being compensated by a reduced workload.
From this research and the gathered data I do also expect to find answers to my research sub questions, namely:
• To what extent does an increased level of health contribute to an increased productivity in the assembly line?
Through preventive measures the physical, motoric, cognitive and to some extent the sensoric abilities can be increased and result in a higher level of health, which hypothetically could result in an overall motoric improvement and therefore contribute to the increase of productivity within the aged staff at the assembly line.
• To what extent can innovations in assembly lines increase productivity?
The increasing need of operator problem solving skills in the job rotation scheme, contributes positively to the learning curve. If communication is stimulated and an open innovation approach is adapted the organization can profit from the increasing innovativeness of their aged staff. They could contribute to optimalisation of the manufacturing process through their gained problem solving skills, inventiveness and synergy effects.

The limitation of this research is that there is no evidence that the generalized level of health within aged staff has a significant impact on the efficiency of the organization. Efficiency can be regarded as a factor, which is determined by the management and not by the staff. Therefore not only the argumentation that an increased level of health increases the productivity of the staff should be proven first, but also if this productivity has an influence on the efficiency of the company.
A further limitation to this research is the comparability of data, which is gathered from two completely different industries (automotive and high-tech electronics) that could make the results of the comparison irrelevant because of the different sectors they supply. High-tech electronics assembly lines could vary a lot from automobile assembly lines, therefore it has to be proven that the job rotation strategy will have the same effect in both industry sectors.
The final limitation can be the problem of translating the results to another industry. It can turn out that the outcomes are so specific that there will be no added value for other industries besides those researched. In the worst-case scenario the outcomes will not be even valuable for the companies, which are being researched because the results will be diffused by the different demographics of those industry sectors.

Allwood, J.M., & Lee, W.L. (2004): The impact of job rotation on problem solving skills. In: Int. J. Prod. Res., (2004), vol. 42, no. 5, 865 – 881.
Arnone, W.J. (2006): Retirement Plan Design Approaches: Are Employers Prepared for the Ageing of U.S. Workforce? In: Benefits Quarterly, 1 – 6.
Azizi, N., Zolfaghari, S., & Liang, M. (2009): Modelling job rotation in manufacturing systems: The study of employee’s boredom and skill variations. In: Int. J. Production Economics 123, (2010), 69 – 85.
European Foundation for the Improvement of Living and Working Conditions (2003): Age and Working Conditions in the European Union. Dublin.
Frazer, M.B., Norman, R.W., Wells, R.P., & Neumann, W.P. (2003): The effects of job rotation on the risk of reporting low back pain. In: Ergonomics, (2003), vol. 46, no. 9, 904 – 919.
Jacobs, D, (2007): Adding Values: The cultural side of innovation. ArtEZ Press. ISBN 9789089101242, 27 – 51.
Keyserling, W.M., Armstrong, T.J., & Punnet, L (1991): Ergonomic job analysis: a structures approach for identifying risk factors for low back pain at work. In: American Journal of Public Health, 91, 1069 – 1075.
Kher, H. V., Malhorta, M. K., Philipoom, P. R., & Fry, T. D. (1999): Modelling simultaneous worker learning and forgetting in dual resource constrained systems. In: European Journal of Operational Research, 115, 158 – 172.
Landsbergis, P.A. (2007): Interventions to Reduce Job Stress and Improve Work organization and Worker Health. In: Unhealthy Work, Chapter 11, 198 – 208.
Paton, N. (2010): Report predicts future with an ageing, less healthy workforce. In: Occupational Health, 00297917, Vol. 62, Issue 7.
Raina, S.M., & Dickerson, C.R. (2008): The influence of job rotation and task order on muscle fatigue: A deltoid example. In: Work 34, (2009), DOI 10.3233/WOR-2009-0917, IOS Press, 205 – 213.
Schlick, C.M. (2010): Age-Differentiated Work Systems. In: Occupational Ergonomics 9 (2010) 65-66, DOI 10.3233/OER-2010-0171, IOS Press, 1 – 3.
Streb, C.K., Voelpel, S.C., & Leibold, M. (2008): Managing the aging workforce: Status quo and implications for the advancement of theory and practice. In: European Management Journal 26, 1 – 10.
Streb, C.K., Voelpel, S.V., & Leibold, M. (2009): Aging Workforce Management in the Automobile Industry: Defining the Concept and its Constituting Elements. In: Zeitschrift für Personalforschung, 23 – 1, 1 – 20.
Sülzenbrück, S., Hegele, M., Heuer, H., & Rinkenauer, G. (2010): Generalized slowing is not that general in older adults: Evidence from a tracing task. In: Occupational Ergonomics 9, DOI 10.3233/OER-2010-0176, IOS Press, 111 – 117.
Thun, J.H., Größler, A., Miczka, S. (2007): The impact of the demographic transition on manufacturing: Effects of an ageing workforce in German industrial firms. In: Journal of Manufacturing and Technology Management, (2007), vol. 18, no. 8, DOI 10.1108/17410380710828299, 985 – 999.
Weichel, J., Stanic, S., Diaz, J.A.E., & Frieling, E. (2010): Job rotation – Implications for old and impaired assembly line workers. In: Occupational Ergonometrics 9, DOI 10.3233/OER-2010-0172, IOS Press, 67 – 74.