Predicting passenger seat comfort and discomfort on the basis of human, context and seat characteristics: a literature review.

This literature review focused on passenger seat comfort and discomfort in a human-product-context interaction. The relationships between anthropometric variables (human level), activities (context level), seat characteristics (product level) and the perception of comfort and discomfort were studied through mediating variables, such as body posture, movement and interface pressure. It is concluded that there are correlations between anthropometric variables and interface pressure variables, and that this relationship is affected by body posture. The results of studies on the correlation between pressure variables and passenger comfort and discomfort are not in line with each other. Only associations were found between the other variables (e.g. activities and seat characteristics). A conceptual model illustrates the results of the review, but relationships could not be quantified due to a lack of statistical evidence and large differences in research set-ups between the reviewed papers. Practitioner Summary: This literature review set out to quantify the relationships between human, context and seat characteristics, and comfort and discomfort experience of passenger seats, in order to build a predictive model that can support seat designers and purchasers to make informed decisions. However, statistical evidence is lacking from existing literature.

Activities, postures and comfort perception of train passengers as input for train seat design.

Working in the train is a part of new ways of working. However, the ideal working position is unknown. Moreover, the ideal position for leisure and relaxing is also unknown. This article defines what activities train passengers mainly perform and which corresponding postures are seen. Based on the observations on actual train rides, four main activities could be identified: Reading, Staring/sleeping, Talking and Working on laptop. Working on laptop was the activity with the longest duration and talking had the shortest duration. Associated with these four activities, a top eight of different postures were observed. Except for headrest comfort, comfort scores were not significantly different between activities. The top eight corresponding postures combined with comfort scores showed that per activity different postures were observed and the comfort scores varied in relation to the combination of posture and activity. Nearly for all activities, the majority of passengers preferred adjustability options to fit the seat to the performed activity.

The effects of precision demands during a low intensity pinching task on muscle activation and load sharing of the fingers.

High precision demands in manual tasks can be expected to cause more selective use of a part of the muscular synergy involved. To test this expectation, load sharing of the index finger and middle finger was investigated during a pinching task. Myoelectric activation of lower arm and neck-shoulder muscles was measured to see if overall level of effort was affected by precision demands. Ten healthy female subjects performed pinching tasks with three levels of force and three levels of precision demands. The force level did not significantly affect the relative contribution of the index and middle finger to the force. Higher precision demands, however, led to higher contribution of the index finger to the pinch force. Consequently, a more selective load of the forearm and hand occurs during tasks with high precision demands. The variability of the force contribution of the fingers increased during the task. No effects of precision demand on the activation of forearm and neck-shoulder muscles were found. Force level did affect the EMG parameters of several muscles. The effects were most apparent in the muscles responsible for the pinch force, the forearm muscles. Activation of these muscles was higher at higher force levels. In the trapezius muscle at the dominant side EMG amplitudes were lower at the high pinch force compared to the low force and median force conditions.

One set of pliers for more tasks in installation work: the effects on (dis)comfort and productivity.

In installation work, the physical workload is high. Awkward postures, heavy lifting and repetitive movements are often seen. To improve aspects of the work situation, frequently used pliers were redesigned to make them suitable for more cutting tasks. In this study these multitask pliers are evaluated in comparison to the originally used pliers in a field study and a laboratory study. For the field study 26 subjects participated divided into two groups according to their type of work. Ten subjects participated in the laboratory study. The multitask plier appeared to result in more comfort during working, more relaxed working and more satisfaction. No differences in productivity were found. In conclusion, the multitask pliers can replace the originally used pliers and are suitable for more tasks than the original pliers. The installation workers have to carry less pliers by using the multitask pliers.

New ways of working: does flexibility in time and location of work change work behavior and affect business outcomes?

In the changing modern economy some new factors have been addressed that are of importance for productivity and economic growth, such as human skills, workplace organization, information and communication technologies (ICT) and knowledge sharing. An increasing number of companies and organizations are implementing measures to better address these factors, often referred to as 'the New Ways of Working (NWW)'. This consists of a large variety of measures that enable flexibility in the time and location of work. Expectations of these measures are often high, such as a reduction in operating costs and an increase of productivity. However, scientific proof is still lacking, and it is worth asking whether al these implementations actually cause a change in work behavior and effect business outcomes positively. This article describes a case study of three departments (total of 73 employees) that changed from a traditional way of working towards a new way of working. Questionnaires and a new developed objective measurement system called 'work@task' were used to measure changes in work behavior (i.e. increased variation in work location, work times and a change towards NWW management style) and the effect on business objectives such as knowledge sharing, employees satisfaction, and collaboration.

New Ways of Working: does flexibility in time and location of work change work behavior and affect business outcomes?

In the changing modern economy some new factors have been addressed that are of importance for productivity and economic growth, such as human skills, workplace organization, information and communication technologies (ICT) and knowledge sharing. An increasing number of companies and organizations are implementing measures to better address these factors, often referred to as 'the New Ways of Working (NWW)'. This consists of a large variety of measures that enable flexibility in the time and location of work. Expectations of these measures are often high, such as a reduction in operating costs and an increase of productivity. However, scientific proof is still lacking, and it is worth asking whether al these implementations actually cause a change in work behavior and effect business outcomes positively. This article describes a case study of three departments (total of 73 employees) that changed from a traditional way of working towards a new way of working. Questionnaires and a new developed objective measurement system called 'work@task' were used to measure changes in work behavior (i.e. increased variation in work location, work times and a change towards NWW management style) and the effect on business objectives such as knowledge sharing, employees satisfaction, and collaboration.

Comparison of four specific dynamic office chairs with a conventional office chair: impact upon muscle activation, physical activity and posture.

Prolonged and static sitting postures provoke physical inactivity at VDU workplaces and are therefore discussed as risk factors for the musculoskeletal system. Manufacturers have designed specific dynamic office chairs featuring structural elements which promote dynamic sitting and therefore physical activity. The aim of the present study was to evaluate the effects of four specific dynamic chairs on erector spinae and trapezius EMG, postures/joint angles and physical activity intensity (PAI) compared to those of a conventional standard office chair. All chairs were fitted with sensors for measurement of the chair parameters (backrest inclination, forward and sideward seat pan inclination), and tested in the laboratory by 10 subjects performing 7 standardized office tasks and by another 12 subjects in the field during their normal office work. Muscle activation revealed no significant differences between the specific dynamic chairs and the reference chair. Analysis of postures/joint angles and PAI revealed only a few differences between the chairs, whereas the tasks performed strongly affected the measured muscle activation, postures and kinematics. The characteristic dynamic elements of each specific chair yielded significant differences in the measured chair parameters, but these characteristics did not appear to affect the sitting dynamics of the subjects performing their office tasks.

Office task effects on comfort and body dynamics in five dynamic office chairs.

In the present study, we investigated the effect of office tasks on posture and movements in field settings, and the comfort rating for chair characteristics and correlation with type of task. The tasks studied were: computer work, telephoning, desk work and conversation. Postures, movements, chair part inclinations and comfort rating data were collected from 12 subjects. Computer work showed the lowest physical activity, together with upright trunk and head position and low backrest inclination. Conversation shows the highest activity of head legs and low back together with the highest cervical spine extension. In contrast, desk work provoked the most cervical spine flexion and showed the second lowest activity. The telephoning tasks showed medium activity and the highest kyphosis. Conversation showed the highest backrest inclination. Positive comfort relations were found for computer work and a "swing system" chair, for telephoning and an active longitudinal seat rotation, and for desk work and a chair with a three-dimensionally moveable seat.

Effects of differences in office chair controls, seat and backrest angle design in relation to tasks.

In this study the influence of chair characteristics on comfort, discomfort, adjustment time and seat interface pressure is investigated during VDU and non-VDU tasks: The two investigated office chairs, both designed according to European and Dutch standards are different regarding: 1) seat cushioning and shape, 2) backrest angle and 3) controls. Thirty subjects in total, both male and female, participated in two experiments: twenty in the first and ten in the second. Significant differences are found for ease of adjustment and adjustment time of controls, independent of the tasks. Related to tasks, a significant difference was found for the backrest range of motion. For non-VDU tasks a larger range of backrest motion was preferred by 70% of the subjects. The chair design differences were most clear for comfort and adjustment time of controls, followed by comfort of backrest angle. No differences are found between seat pan comfort and discomfort, first impressions and peak interface pressure.