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In this paper, a smart office chair with movable textile sensors to monitor sitting position during the workday is presented. The system consists of a presence textile capacitive sensor with different levels of activation with a signal conditioning device. The proposed system was integrated into an office chair to detect postures that could provoke musculoskeletal disorders or discomfort. The microcontroller measured the capacitance by means of a cycle count method and provided the position information in real time. The information could be analysed to set up warnings to prevent incorrect postures or the necessity to move. Five participants assumed a series of postures, and the results showed the workability of the proposed smart chair. The chair can be provided as a new tool for companies, hospitals, or other institutions to detect incorrect postures and monitor the postures of people with reduced mobility. This tool can optimise control procedures or prevent occupational risks. [ABSTRACT FROM AUTHOR]

Chair design is one of the most demanding and most challenging tasks for designers, to which creative efforts of numerous architects have been continuously linked. Since the beginning of the twentieth century the intensity of these efforts has not diminished. By creating an ideal microcosm around an essential everyday object, architects also express their understanding of space and time. A chair, like architecture, occupies a position in space that it also defines. The paper analyses three groups of chairs characteristic of the 20th century, different in terms of typology and morphology. Their architectonics are marked by a specific functional, formal and constructive idea, by concrete production possibilities and by technological procedures in the working of individual materials. Notably, reclining chairs, cantilever chairs with steel tube constructions and office chairs. The model of analysis put forward could also serve as a point of departure for future more extensive research into the same, or different, typological and morphological design. Three Croatian chair models are placed in the context of the pertaining design. [ABSTRACT FROM AUTHOR]

Chair design is one of the most demanding and most challenging tasks for designers, to which creative efforts of numerous architects have been continuously linked. Since the beginning of the twentieth century the intensity of these efforts has not diminished. By creating an ideal microcosm around an essential everyday object, architects also express their understanding of space and time. A chair, like architecture, occupies a position in space that it also defines. The paper analyses three groups of chairs characteristic of the 20th century, different in terms of typology and morphology. Their architectonics are marked by a specific functional, formal and constructive idea, by concrete production possibilities and by technological procedures in the working of individual materials. Notably, reclining chairs, cantilever chairs with steel tube constructions and office chairs. The model of analysis put forward could also serve as a point of departure for future more extensive research into the same, or different, typological and morphological design. Three Croatian chair models are placed in the context of the pertaining design.

This study serves the purpose of assisting users in selecting a comfortable seat surface material for office chairs and enhancing users' comfort while using office chairs. To address the issue that the selection of traditional seat surface material is too subjective and that the prediction effect is poor, an improved sparrow search algorithm (ISSA) optimized least squares support vector machine (LSSVM) method for office chair seat surface material comfort prediction has been proposed. Sparrow Search Algorithm (SSA) was optimized with Sobol sequences, nonlinear inertial weights, and a crisscross optimization algorithm to produce the Improved Sparrow Search Algorithm (ISSA), and then the relevant parameters of the LSSVM algorithm were optimized with the modified algorithm to improve its prediction performance. The prediction accuracy of the ISSA-LSSVM model is as high as 95.75% by combining the body pressure distribution experiments; the root mean square error (RMSE) is 0.29; the goodness of fit (R2) is 0.92; the mean absolute error (MAE) is 0.24; the standard deviation (RSD) is 5.99%. The ISSA-LSSVM model predicts seat surface material comfort more accurately and reliably. This strategy can assist consumers to narrow down their seat surface material choices and even suggest an optimal selection. In this way, it can boost users' pleasure with office chairs, which has great potential for wide application. [ABSTRACT FROM AUTHOR]

The health consequences of prolonged sitting in the office and other work chairs have recently been tried to be alleviated or prevented by the application of modern technologies. Smart technologies and sensors are installed in different parts of office chairs, which enables monitoring of seating patterns and prevents positions that potentially endanger the health of users. The aim of this paper is to provide an overview of previous research in the field of the application of smart technologies and sensors built into office and other types of chairs in order to prevent diseases. The articles published in the period 2010-2020 and indexed in WoS CC, Scopus, and IEEE Xplore databases, with the keywords “smart chair” and “sensor chair” were analysed. 15 articles were processed, with their research being based on the use of different types of sensors that determine the contact pressures between the user’s body and stool parts and recognise different body positions when sitting, which can prevent negative health consequences. Analysed papers prove that the use of smart technology and a better understanding of sitting, using various sensors and applications that read body pressure and determine the current body position, can act as preventive health care by detecting proper heart rate and beats per minute, the activity of individual muscle groups, proper breathing and estimates of blood oxygen levels. In the future research, it is necessary to compare different types of sensors, methods used and the results obtained in order to determine which of them are most suitable for the future development of seating furniture for work.

In this paper, a smart office chair with movable textile sensors to monitor sitting position during the workday is presented. The system consists of a presence textile capacitive sensor with different levels of activation with a signal conditioning device. The proposed system was integrated into an office chair to detect postures that could provoke musculoskeletal disorders or discomfort. The microcontroller measured the capacitance by means of a cycle count method and provided the position information in real time. The information could be analysed to set up warnings to prevent incorrect postures or the necessity to move. Five participants assumed a series of postures, and the results showed the workability of the proposed smart chair. The chair can be provided as a new tool for companies, hospitals, or other institutions to detect incorrect postures and monitor the postures of people with reduced mobility. This tool can optimise control procedures or prevent occupational risks.

Copyright of Wood Industry / Drvna Industrija is the property of Drvna Industrija and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives The purpose of this paper is to investigate the effects of the seat cushion contour and the sitting posture on the seat pan interface pressure distribution and subjective comfort perception. Material and Methods Overall, 16 volunteers typed a text passage on a laptop while seated, by assuming 3 kinds of common sitting postures (forward, relaxed and upright) in 4 seat cushion configurations: chair only, and chair with 1 of 3 supplementary cushions. Pressure data and cushion comfort ratings were collected in the experiment. Results It was found that the sitting posture and the seat cushion contour had different impacts on surface pressure. The seat cushion contour had an impact on pressure parameters and pressure distribution on the seat pan, while the sitting posture affected the location of peak pressure on the seat pan. The correlation analysis revealed that the subjective comfort rating was significantly correlated with average pressure (AP) and mean peak pressure (MPP). Conclusions The conclusion was that the cushion contour had a greater effect on seat pan interface pressure parameters than the sitting posture. Notably, AP and MPP can be indicators for assessing seat cushion comfort in a short-term perspective. Int J Occup Med Environ Health. 2020;33(5):675–89

This study serves the purpose of assisting users in selecting a comfortable seat surface material for office chairs and enhancing users’ comfort while using office chairs. To address the issue that the selection of traditional seat surface material is too subjective and that the prediction effect is poor, an improved sparrow search algorithm (ISSA) optimized least squares support vector machine (LSSVM) method for office chair seat surface material comfort prediction has been proposed. Sparrow Search Algorithm (SSA) was optimized with Sobol sequences, nonlinear inertial weights, and a crisscross optimization algorithm to produce the Improved Sparrow Search Algorithm (ISSA), and then the relevant parameters of the LSSVM algorithm were optimized with the modified algorithm to improve its prediction performance. The prediction accuracy of the ISSA-LSSVM model is as high as 95.75% by combining the body pressure distribution experiments; the root mean square error (RMSE) is 0.29; the goodness of fit (R2) is 0.92; the mean absolute error (MAE) is 0.24; the standard deviation (RSD) is 5.99%. The ISSA-LSSVM model predicts seat surface material comfort more accurately and reliably. This strategy can assist consumers to narrow down their seat surface material choices and even suggest an optimal selection. In this way, it can boost users’ pleasure with office chairs, which has great potential for wide application.

The world of ergonomic evaluation considerate the human biomechanics and anthropometric measurement an integral part of product design and development work. In this paper, we have given an attempt to design an ergonomically fitted office chair suitable for Bangladeshi people. In this paper, the anthropometric data analysis has been done in order to determine the necessary dimensions suitable for the office chair. Lastly, an ergonomically fitted office chair is designed based on this anthropometric data analysis. The concept of the paper is to focus on the dimensional changes that the Bangladeshi people need for their comfort in the ergonomic office chair. The structural difference in different regions makes us inspired to think about the office chair ergonomics for Bangladeshi people. In short, this paper reflects the entire process of designing an ergonomic office chair suitable for them.

Copyright of Mugla Journal of Science & Technology is the property of Mugla Journal of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is not currently known if biomechanical factors contribute to low back pain (LBP) during prolonged sitting. Thus, this study recruited 90 participants (61 with no history of LBP, and 29 with) to sit for 1 hour where back electromyography, spine posture, and perceived pain ratings (PPR) were collected. Participants were classified as Pain Developers (PD) or Non-Pain Developers (NPD) based on their maximum PPR. PDs had significantly higher PPR (p = 0.000) and lower number of spine fidgets (p = 0.004) than NPDs. There was a significant interaction between clinical health history and pain group (p = 0.037) for PPR. Besides fidget frequency, there were no biomechanical differences between pain groups. Therefore, sitting-induced back pain does not appear to be due to posture or muscle activity; however, it may be related to micro-movement strategies. Future work should explore fidgeting further and whether healthy PDs are at risk for clinical LBP in the future. Practitioner summary: We have replicated the differential transient sitting-induced pain response observed in previous studies. Pain developers do not sit differently than non-pain developers, although they do appear to move less. More research is warranted to better understand these groups and the relationship between pain developers and future cases of back pain. Abbreviations: LBP: low back pain; PG: pain group; PD: pain developer; NPD: non-pain developer; +veHx: positive clinical history for low back pain; -veHx: negative clinical history for low back pain; RTS: right thoracic erector spinae; LTS: left thoracic erector spine; RLM: right lumbar multifidus; LLM: left lumbar multifidus; MVC: maximum voluntary contraction; Pelvic N: normalized pelvic angle; ANOVA: analysis of variance; SD: standard deviation [ABSTRACT FROM AUTHOR]

The studies of office chair constructions have identified differences in perception of comfort provided by different types of seats. Four seat constructions and the comfort provided to the users were compared by means of subjective indicators. After a two-day sitting on each of the studied chairs, the subjects scored their perception of comfort and discomfort, using the questionnaire with 17 statements. Unlike most similar studies, subjects evaluated seats on their own work places and in the environment to which they are accustomed. Constructional forms of the seat and materials that contributed more to the sense of comfort by minimizing fatigue and pains developed by sitting were determined. Results have shown that the chair with a net is significantly more comfortable than other chairs. The chair with molded PU foam is significantly more comfortable than the chair with springs, but statistically it does not differ significantly from the chair with slabstock PU foam. It has been concluded that the chair with a net got higher scores, which might be attributed to its frame construction and the absence of a hard base under the sitting surface.

The analysis and regulation of workplace, working instruments, the comfort of office chair, business environment (sound, lighting, climate, vibration, temperature, and humidity), work and break times, analysis and editing of the organization, are some of the topics of interest of ergonomics. Environmental impact and conditions have important role on the employee’s working comfortably and efficiently. Therefore these conditions need to be aligned to the human body nature. Unsuitable working conditions (noise, etc.) cause additional load, which the human body endures, and this additional load reveals the signs of tiredness in the body. Even an office environment, unsuitable physical environment impairs health of workers and reduces the performance. Therefore, office climate, environmental factors such as lighting and noise must be harmonized with the employee’s body nature in all working environments. Seating comfort is one of the important factors affecting the performance of employees in the office environment. There are so many studies about chair dimensions and the disorders on human body which were caused by the inappropriate chair dimensions and sitting positions. However, there are a spot of studies about the surface of the chair and the discomfort caused by the chair cover and its negative performance effects. In this study, some results of seat cover analysis for the design of an ergonomic chair. Recently, ease of cleaning, low cost advantages caused the increasing of the use of artificial leather especially on the surface of the seat used in offices. The physical properties of natural leather and artificial leather were compared as the candidate covers to be used on the design of an ergonomic office chair.

Copyright of Dokuz Eylul University Muhendislik Faculty of Engineering Journal of Science & Engineering / Dokuz Eylül Üniversitesi Mühendislik Fakültesi Fen ve Mühendislik Dergisi is the property of Dokuz Eylul Universitesi Muhendislik Fakultesi Fen ve Muhendislik Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Office employees are exposed to acoustic noise, especially in an open office environment. Passive or active headsets sufficiently reduce the level of noise, but their long-time wear is uncomfortable. The paper presents an active headrest system built into a chair. Feedforward control is utilized with multiple reference microphones, and flexible gooseneck microphones serve as error sensors. The reference sensors surround the chair, allowing the suppression of sound waves arriving from any direction. The concept of multiple reference control has been tested by extensive experiments showing that multiple reference signals help to increase the suppression in normal rooms where reverberation occurs, even if only one noise source is present. The preliminary experiments are completed by a series of simulations aiming to explore the zones of quiet at the user's ears. The paper introduces the construction details of the noise-canceling chair: The two loudspeakers are controlled by the signals of two error microphones and four reference signals. The controller is based on the normalized filtered error least mean squared algorithm, implemented on an Analog Devices ADSP-21262 signal processor-based hardware. Experimental results are reported that show the efficient suppression of tonal, as well as broadband disturbances. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to determine which office chair feature is better at improving spine posture in sitting. Method: Participants (n = 28) were radiographed in standing, maximum flexion and seated in four chair conditions: control, lumbar support, seat pan tilt and backrest with scapular relief. Measures of lumbar lordosis, intervertebral joint angles and sacral tilt were compared between conditions and sex. Results: Sitting consisted of approximately 70% of maximum range of spine flexion. No differences in lumbar flexion were found between the chair features or control. Significantly more anterior pelvic rotation was found with the lumbar support (p = 0.0028) and seat pan tilt (p < 0.0001). Males had significantly more anterior pelvic rotation and extended intervertebral joint angles through L1–L3 in all conditions (p < 0.0001). Conclusion: No one feature was statistically superior with respect to minimising spine flexion, however, seat pan tilt resulted in significantly improved pelvic posture. Practitioner Summary:Seat pan tilt, and to some extent lumbar supports, appear to improve seated postures. However, sitting, regardless of chair features used, still involves near end range flexion of the spine. This will increase stresses to the spine and could be a potential injury generator during prolonged seated exposures. [ABSTRACT FROM AUTHOR]

Aiming at analyzing of the phenomenon of “back rub” in the process of the chair linkage, the condition of achieving the “zero back rub” of the office chair was obtained. The parametric modeling of the linkage mechanism of the office chair was carried out on ADAMS/View to realization the performance of “zero back rub” in the process of linkage. and connections between point1 with point 3 and point 2 with point 3 was established. The point 1 is both on the back of the chair and on the back of people. The point 2 is both on the back of the chair and on the waist of people. The point 3 is both on the board of seat and on the hips of people. In the process of linkage, the line length is the known standard value, and the influence degree of many variables on the objective function was analyzed, and the main design variables were determined. The normalized weighting method was used to optimize and validate. The optimization results show that in the process of linkage, the chair achieves the target of “zero rub back” and the comfort of the office chair was increased. [ABSTRACT FROM AUTHOR]

Thermal comfort is related to human physiological reactions. In order to maintain a constant internal temperature, the human body must dissipate heat in a warm climate, and prevent heat losses in a cold climate. The overall sensation of comfort accompanies the warmest part of the body in a warm environment and the coldest one in a cold environment. Chair design and clothing may affect the difference in sensitivity between certain parts of the body, that is, they may affect thermal comfort. This research focused on subjective sensation of warmth and moisture while sitting on offi ce chairs. The subjective method of evaluating thermal discomfort is based on ISO 7730:2005 standard, according to which a questionnaire was made for this research. Six subjects took part in the research. They were sitting on five different office chairs as they performed their usual jobs in controlled conditions. From the point of view of the evaluation of the sensation of warmth, all chairs were evaluated neutrally. The sensation under the buttocks and thighs was reported to be somewhat warmer, while the sensation on the back was reported to be somewhat colder, which was affected by the design of the back of the chair. No correlation has been proven between the actual temperature and moisture measurements and subjective evaluations of thermal comfort, in spite of a number of direct links. The use of the present method offers the possibility of further research into this subject, which would prove more thoroughly a correlation between design and construction solutions of office chairs and the comfort perceived by sitting persons.