Mismatch of classroom furniture and student body dimensions: empirical findings and health implications

A dimensional design of tractor seat based on Iranian anthropometric characteristics

BACKGROUND

The dimensional seat design process should consider both the users' tasks and their physical characteristics.

OBJECTIVE

To use an approach for the design and evaluation of seat dimensions based on the anthropometric characteristics of the Iranian population and the requirements of tractor operators.

METHODS

Some existing equations relating the seat dimensions to anthropometric characteristics were modified according to logical justifications and international standards. A new mathematical-statistical method was used to extract the equations estimating the constant seat dimensions based on the theoretical maximizing of the accommodation level. In addition, an Overall Seat Accommodation Score (OSAS) was developed to represent the mean of seat dimensions accommodation level and dimensional accommodation equality, simultaneously.

RESULTS

The dimensional seat design can be affected under different conditions of adjustability, esthetic, and space limitations. However, it was shown that it is possible to improve the design of tractor seats without any significant increase in the final cost and complexity.

CONCLUSION

A new approach was used for tractor seats for a sample of Iranian operators and can be used for the design and evaluation of tractor seats for other target populations.

The estimation of different body dimensions of children aged 6-11 years for the needs of furniture designers

BACKGROUND

There are some rules that furniture designers must take into consideration to design ergonomic furniture. The main design principle is the target group for which the furniture will be designed, considering the dimensions of people who use the furniture.

OBJECTIVE

The paper presents the correlation between 12 parts of children's body, as well as the proportion between stature and 11 other parts of the body which are used for the purposes of furniture and interior designers.

METHODS

Field measurements include: Stature (S), Sitting height (She), Shoulder height (Sh), Popliteal height (Ph), Hip width (Hb), Elbow rest height (Erh), Buttock-popliteal length (Bpl), Buttock-knee length (Bkl), Thigh clearance (Tc), Eye height sitting (Eh), Knee height (Kh) and Shoulder breadth (Sb) to pupils aged 6-11 (grades 1 to 5). The measurements were done in 687 children in 12 primary schools in 4 different regions in Kosovo.

RESULTS

The data of the study shows that, in general, there is a correlation (in some parts strong and in some medium) for the measured parts. Also, the study presents the proportion between the stature and other parts of the body which are necessary for the design of children's furniture.

CONCLUSION

Using this data will enable furniture designers to easily target the dimensions of the group they will design, even by measuring only one dimension, i.e. stature and then setting the proportions for each piece separately.

Computer-aided ergonomic analysis of primary school furniture dimensions

The objective of this study was to determine the match level of school furniture with student dimensions and conduct a pilot study to examine practicality of a computer-aided ergonomic analysis software with a Motion Capture System (MoCap) for the purpose of improving school furniture design process in terms of determining optimum dimensions. The research involved measuring the anthropometric data of 218 voluntary primary school students in Mugla, Turkiye and the dimensions of the existing school desks they use. The compatibility between the students' anthropometry and the existing school desks were analysed by using reference equations. Computer-aided ergonomic analysis performed only for seat and desk height. Four virtual human model and ten different school desks in various dimensions were created and evaluated according to joint reaction forces and muscle activations in three different postures by using Anybody Modelling System (AMS). The results of compatibility level showed that there were significant incompatibilities between the students' anthropometry and the existing school desks, with 80% of seat heights and 96% of desk heights being too high. Overall, in order to assess the optimal school desk dimensions, ergonomic analyses provided data indicating reduced joint reaction forces and muscle activations within the musculoskeletal system for the seat and desk height dimensions determined using reference equations. Also, the findings from the ergonomic analysis revealed valuable information on how even minor dimensional modifications to school desks can affect the musculoskeletal system.Practitioner summary: The study examined the impact of simulating student-school desk matching in various sizes and postures within a virtual environment using computer-aided ergonomic analysis software. The analysis focused on specific local areas of the musculoskeletal system to determine optimum school desk dimensions. The results indicated that the software has a potential in facilitating school furniture design based on user's anthropometric measurements. However, a multidisciplinary team is required to make more detailed analysis.

Approach for ergonomic assessment of self-propelled combine harvester seats based on anthropometric body dimensions

Objectives. The seat dimensions of self-propelled combine harvesters are designed without consideration of body dimensions of the user population and vary with make and models of combines. Methods. This research proposes a method to determine the percentage of seat match, upper mismatch and lower mismatch using the anthropometric body dimensions of Indian harvester operators. The seat dimensions of five popular combine harvester makes were measured and compared to the body dimensions of the operators. Results. The selected seats had 100, 44-70, 81-96, 98-100, 63-83, 59-94 and 55-97% mismatch for seat height, seat length, seat pan breadth, seat backrest height, upper backrest breadth, lower backrest breadth and steering wheel clearance, respectively. These data were used to recommend seat dimensions for combine harvesters. Seat height, seat length, seat pan breadth, seat backrest height, upper backrest breadth, lower backrest breadth and steering wheel clearance are recommended as 399, 362, 456, 400, 243, 386 and 190 mm, respectively. Conclusions. The recommended seat dimensions matched the user population anthropometric dimensions 94-100%. This approach will help to assess seat dimensions based on anthropometric data for a comfortable posture to prevent health risks such as musculoskeletal disorders (MSDs) among operators.

Ergonomic evaluation of school furniture in Slovenia: From primary school to university

BACKGROUND:

Adequate school furniture is important to prevent musculoskeletal discomfort among students.

OBJECTIVE:

The aim of the study was to assess the suitability of school furniture compared to body dimensions of students.

METHODS:

A cross-sectional study included a total of 442 students from primary school, secondary school, and university. Nine body dimensions along with five furniture dimensions were measured and equations for mismatch criteria were applied.

RESULTS:

In primary school, differences in body dimensions were more evident among students of different age, while in secondary school and university, differences between male and female students became more apparent. The mismatch for desk height ranged from 100.0% at primary school to 48.0% at university. Similarly, the seat height mismatch was the most evident in primary school (89.7% –94.6%), lower at university (52.0%) and the lowest in secondary school (18.0%). The seat depth mismatch was present among all groups, ranging from 23.1% to 40.4%, and was in general more pronounced in males. Seat to desk clearance mismatch was the most evident among secondary school students. In primary school, seat and desk height were generally too high for most of students.

CONCLUSIONS:

Specific differences in body dimensions among groups of students of different age and gender were observed and a high student-furniture mismatch was identified in all educational institutions. Implementation of adjustable school furniture, covering at least two size marks, is needed to provide ergonomic and healthy learning conditions and to further enhance the comfort and well-being of students in the classroom.

The accuracy and reliability of three instruments used to assign school furniture

BACKGROUND: Students spend a high number of hours being seated while at school. In order to find the correct adjustment between school furniture and the anthropometric characteristics, specific knowledge and tools are necessary. OBJECTIVE: The objective of the study is to evaluate the accuracy and reliability of the measurers with different instruments, as well as contrast the differences between the values that were obtained by the different examiners. METHODS: Measurements were taken independently by one expert examiner and two inexperienced teachers from the school. They used a measuring tape, a segmometer and an anthropometer for the anthropometric measurements. The statistical tests conducted: Kolmogorov-Smirnov test, Intraclass Correlation Coefficient, Bland and Altman method, Standard Error of Measurement, Technical Error of Measurement and relative TEM with a level of significance of ρ ≤ 0.05. RESULTS: A total of 108 students (8.87±1.67 years; 40.7% girls) participated in the study. The non-expert measurers had good accuracy and reliability, but they far exceeded the error percentages of the expert, obtaining the worst results in the shoulder measurement. The instrument with the lowest affinity between the inexperienced measurers was the anthropometer CONCLUSIONS: In order to assign furniture in the schools, the experts should continue using the anthropometer. The inexperienced measurers can use more accessible instruments in the school environment such as a measuring tape and segmometer.

Discrepancy between pupils’ body and classroom furniture in elementary schools: A case study in the Republic of Kosovo

BACKGROUND: Primary school children spend quite a lot of time sitting in classrooms. For this reason, it is necessary to make a scientific analysis of children’s body dimensions and compare them with the furniture dimensions where they sit. OBJECTIVES: The main aim of this paper is to present anthropometric data for pupils in primary schools in the Republic of Kosovo and give recommendations for school furniture design. METHODS: Measurements were made in the public schools of four different regions in the Republic of Kosovo. The study includes 720 children from 12 different elementary schools with first and fifth graders (6–11 years old).- Twelve body parts were measured: Stature, sitting height, shoulder height, lower leg length, hip breadth, elbow height, buttock-popliteal length, thigh clearance, eye height, shoulder breadth, and knee height. The descriptive data are calculated in terms of average, standard deviation, and 5th, 50th and 95th percentile. RESULTS: We recommend that the competent authorities in the Republic of Kosovo consider improving the infrastructure of primary schools in terms of furniture size according to the findings presented in this study. CONCLUSIONS: The information presented in this paper on pupils’ anthropometry and the proposed dimensions for school furniture can be used by various bodies in Kosovo including, but not limited to: Ministry of Education Science and Technology,Ministry of Trade and Industry of Kosovo and furniture manufacturing industries as basic information for suitable furniture design for primary school children, as well as school principals to help in furniture selection.

Effects of workstation adjustment to reduce postural exposure and perceived discomfort among office workers - A cluster randomized controlled trial

This study aimed to evaluate the effects of workstation adjustment to reduce postural exposure and perceived discomfort among office workers in a cluster randomized controlled trial. Experimental (EG, n = 31) and control groups (CG, n = 30) were compared before (pre-intervention), immediately (post-intervention), and 3 months after (follow up) the intervention. EG received workstation adjustments and CG did not received the intervention. Postural exposure of head, upper back and upper arms was objectively measured by inclinometers. Overall level of perceived discomfort for the whole body was evaluated using a visual analogue scale (0-100 mm). EG showed a statistically significant reduction on the head (pre: 10.1°, SD 5.7°; post: 6.6°, SD 4.7°) and upper back flexion (pre: 15.4°, SD 10.7°; post: 10.4°, SD 8.4°) from pre to post-intervention. EG also showed a statistically significant reduction from pre (50.7°, SD 9.5°) to post-intervention (42.1°, SD 7.6°) and from pre to follow up (41.6°, SD 6.5°) on upper arm elevation. CG did not show any difference between evaluations. Perceived discomfort increased 7.2 (SD 2.0) mm in CG and decreased 22.1 (SD 2.2) mm in EG between pre and post intervention. The variation between pre intervention and follow up was 4.5 (SD 1.2) mm increase for the CG and 24.1 (SD 1.5) mm of reduction for the EG (P < 0.01). There was no significant difference for the post intervention and follow up for both groups (P > 0.05). The results show evidence of the workstation adjustment to reduce postural exposure and perceived discomfort among office workers.

Anthropometric perspective to classroom furniture ergonomics and the need for standards in Nigerian schools

BACKGROUND: Classroom furniture designs have been implicated in musculoskeletal disorders among school age persons due to high level mismatches between the furniture dimensions and users’ anthropometrics. OBJECTIVE: The objective of the study was to analyze classroom furniture ergonomics at selected primary, secondary and tertiary educational institutions in Nigeria and to understand if there are noticeable patterns in the match/mismatch. METHOD: Anthropometric measures relevant to furniture design were obtained from primary and secondary school children as well as from university undergraduates. The dimensions of classroom furniture available to the participants were also taken and an assessment of the suitability of the furniture was completed. RESULT: The ergonomic evaluation of the classroom furniture available to the study participants revealed enormous discrepancies between the furniture dimensions and the anthropometric measures of the users. In addition, a pattern was observed in the way the matches/mismatches occurred. The furniture dimensions that matched majority of the users tend to match across the three categories and those that did not match majority of the students, also followed the same pattern. CONCLUSION: The study presents remarkably high levels of mismatches between classroom furniture and users’ anthropometrics and therefore calls for a review of the policies for classroom furniture design in Nigeria, if at all any policy exists.

Assessing the ergonomic status of commonly used chairs in Iran’s universities based on combinational equations and anthropometric indices

BACKGROUND: Inappropriate design of chairs and disproportion with students’ body dimensions can influence their physical and mental health as well as their educational efficiency and concentration. OBJECTIVE: The aim of this study was to examine the ergonomic status of commonly used chairs in Iran’s universities using combinational equations and anthropometric indices. METHODS: Participants in this cross-sectional study were 166 students in Iran. Eleven anthropometric parameters of the students and nine dimensions in seven types of commonly used chairs in Iran’s universities were measured. Combinational equations were used to determine the fitness of the chairs. RESULTS: There was a major mismatch between most students’ anthropometric measurements and the dimensions of the chairs. Backrest height and seat height were the best and the worst features, respectively, according to ergonomic recommendations for chairs. The recommended measurements of seat height, seat depth, seat width, desk height, desk width, desk length, backrest width, backrest height, and desk distance were 332, 420, 436, 245, 95, 511, 426, 550, and 281 mm, respectively. CONCLUSION: None of the commonly used chairs in Iran’s universities were found to be a good fit to the students’ anthropometric dimensions. Therefore, in order to prevent inappropriate body postures, chair designs have to reviewed, and made to fit with Iranian students’ anthropometric data. The recommended measurements obtained in this study can be used to design a suitable ergonomic chair to match with a high percentage of Iranian students.

Improving Work-related Musculoskeletal Disorders for Sewing Machine Operators in Ethiopia

Purpose. The awkwardly designed sewing workstations in the garment industry cause work-related musculoskeletal disorders that cause global health concerns for industrial sewing operators. This study was conducted with the aims of evaluating health risks and improvement interventions for sewing operators in Ethiopia. Materials and methods. Strain index and standardized Nordic Musculoskeletal disorder questionnaires were used for data collection. Binary and multiple logistic regression analysis were used to analyze the data and identify significant factors. Results. The study revealed that operators sitting chair design in the sewing section has significant correlation with the occurrence pain in different body parts particularly in the upper and lower back body parts with a high odds ratio of more than 93% in the low and upper back areas. Hence, the sitting chair was redesigned considering operator's anthropometric measurements and workstation requirements to improve workers safety and productivity. Conclusion. The study concludes that work related musculoskeletal disorders were significant in different body parts was crucial for appropriate intervention in redesigning the sewing workstations particularly the sitting chair to ensure health and safety of industrial sewing operators. The study therefore recommends implementation of the proposed ergonomic sitting chair to improve operators safety and productivity.

Validation of Two Instruments for the Correct Allocation of School Furniture in Secondary Schools to Prevent Back Pain

BACKGROUND

Back pain is common in secondary school students. If we adjust the school furniture to the anthropometric characteristics of the pupils, we will improve their posture and reduce back pain. There is a high degree of mismatch between the furniture used by students and that which should be used. The objectives of this research are to discover the degree of mismatch and validate two instruments that allow a correct allocation of the furniture.

METHODS

The selected sample was 132 secondary students (14.08 ± 1.10 years). An anthropometer was used to determine the ideal height of the chair and table; data were taken from body segments. The recorded values were compared with those obtained by the two measurement instruments to be validated. Inter-measurer and intra-measurer reliability and validation were performed using t-tests and Pearson's coefficient, respectively. Different analysis techniques were used: descriptive, one-way ANOVA, t-test, and effect size. The established level of significance was ρ < 0.05.

RESULTS

The mismatch between the anthropometric dimensions of the students and the existing furniture in the classrooms was 98.5 % for the chairs and 100 % for the tables. The correlational analysis of the instruments to be validated shows an r = 0.993 in the chair and r = 0.996 in the table.

CONCLUSIONS

There is a high degree of mismatch between the furniture and the anthropometric characteristics of the students. The proposed furniture allocation instruments are adequate.

Garments furniture design for Bangladeshi workers considering ergonomic principles

BACKGROUND

In Bangladesh, workers typically spend at least eight hours a day at garment factories in sitting and/or standing position. Prolonged sitting on ergonomically unfit furniture causes back, neck, and shoulder pain, which reduces the working efficiency and leading to low productivity.

OBJECTIVE

The aim of this study is to design ergonomically correct furniture for Bangladeshi garment workers considering multivariate analysis on the anthropometric data.

METHODS

Twelve anthropometric measures and five furniture dimensions were measured. The sample comprised of 600 volunteer workers from different garment industry. The furniture dimensions were compared with the relevant anthropometric characteristics and found a high level of mismatch (e.g. seat height (male 18%, female 94.25%), seat depth (male 96%, female 63.50%), seat width (male 9.50%, female 36.25%), sewing table height (male 56.50%, female 50%), and desk height for inspection, cutting and ironing table (male 100%, female 100%).

RESULTS

New design specifications were proposed of the worker which improved the match percentage. The multivariate anthropometric analysis generated 8 cases and for each case the ranges of anthropometric measurements have been identified.

CONCLUSION

The results will help to design robust ergonomic garments furniture.

Comparison of classroom furniture to anthropometric measures of Turkish middle school students

BACKGROUND

The match between classroom furniture and students' anthropometry is an important factor in students' academic performance.

OBJECTIVE

Our aim was to investigate the ergonomic suitability of the classroom furniture to the students, and to propose design suggestions for both desks and chairs.

METHODS

We analyzed the ergonomics of classroom furniture that students aged 10-14 years old in Turkey currently use. To this end, we selected Maltepe Primary Education School, one of the largest schools in the Çankaya district of Turkey's capital city, Ankara, in which to conduct the study. A sample of 119 students was selected, and seven anthropometric measurements were taken for each of these students. We then calculated five relationships between the dimensions of the furniture and the students' anthropometric measures.

RESULTS

We observed high levels of mismatch rates, with an average of 66.6%and high values of over 95%for the relations of two furniture measures, seat depth (related with buttock-popliteal length) and seat-to-desk height (related with elbow height, sitting). Each anthropometric measure was applied a fit probability distribution, and based on those distributions; we suggested the most appropriate classroom furniture dimensions in order to maximize suitability of the furniture to the anthropometric measures in terms of fixed-size (i.e., non-adjustable) classroom furniture.

CONCLUSIONS

High mismatch rates can be reduced by 52.0%on average based on the classroom furniture dimensions suggested in this study.

Post-COVID-19 ergonomic school furniture design under fuzzy logic

BACKGROUND

Because of wrong sitting position, children have back-pain and related musculoskeletal pain (MPD). Due to inappropriate designed class furniture by not taking into account the children's anthropometric measurements have negative effect on children musculoskeletal systems. The impact of the COVID-19 pandemic crisis has changed the furniture industry's production trends.

OBJECTIVE

This study aimed to develop a new fuzzy based design of ergonomic-oriented classroom furniture for primary school students considering the measured anthropometric dimensions of students' safety, health, well-being, i.e. ergonomic criteria, socio-psychological aspect and post-COVID policies.

METHODS

In the study 2049 number of primary school students are assessed considering COVID-19 pandemic policies and their static anthropometric dimensions were measured between 7-10-year-old (between 1st-4th grade students) and descriptive statistics of children among their ages and genders are calculated; mean, standard deviation, percentiles. The data collected from the students were analyzed quantitatively by using Significance Analysis: Mann-Whitney U test statistic, t-test, Regression Analysis and one-way ANOVA. In the study interviews with experts are performed and fuzzy mathematical model (by using fuzzy-AHP, fuzzy-TOPSIS and fuzzy-VIKOR) is developed to calculate Turkey's three schools' furniture.

RESULTS

Results showed statistically significant differences between two genders. And it is observed that the seating bench height is too high for primary school students and lower than the height of the classroom's blackboard from the floor. Fuzzy Multi Criteria Decision Making Method's (FMCDM) results show that primary school students' ergonomic classroom furniture should be mainly designed by considering "COVID-19 Criteria", "Ergonomic Criteria" and "Socio-Psychological Aspect". Students' existing seating benches and tables are changed by considering post-COVID policies/protocols, Ergonomic Criteria and Socio-Psychological Aspect. And a new seating bench/chair and table's dimensions is proposed in the study.

CONCLUSIONS

Children study at school for long periods and their activities involve long periods of time on their desks in schools. As per the results of the study, it can be concluded that school management must consider the genders, ages of students and take into account the post-COVID policies/protocols while procuring the classroom furniture. The COVID-19 pandemic is the single largest event to have affected children globally in their access to school in recent times; estimates suggest that over 85%of the world's total enrolled learners, 1.5 billion children and youths, have been affected. The coronavirus pandemic also creates dramatic changes for the school furniture.

Effect of an ergonomic intervention involving workstation adjustments on musculoskeletal pain in office workers-a randomized controlled clinical trial

Office workers remain in a awkward position for long periods, which can lead to musculoskeletal symptoms. Ergonomic guidelines are recommended to avoid such problems. Evidence of the long-term effectiveness of ergonomic interventions is scarce. The aim of this randomised controlled trial was to compare pain intensity among office workers who received an ergonomic intervention and a control group before as well as 12, 24, and 36 wk after the intervention. Workers were randomly allocated to a control group (CG) and experimental group (EG). The EG received an ergonomic workstation intervention. Furniture measurements were related to individual anthropometric measurements to identify mismatches. The outcome was pain intensity, which was determined using a numerical pain scale and the Nordic Musculoskeletal Questionnaire. A linear mixed model was created with pain intensity as the dependent variable. Group and time were the independent variables. No significant interactions were found between group and time. Significant differences between groups were found for the pain intensity in the neck, shoulder, upper back, and wrist/hand (p<0.05), with lower intensity in the EG. The intervention reduced pain intensity in the neck, shoulder, upper back, and wrist/hand. However, no reduction in pain intensity was found for the lower back or elbow.

Identifying factors that influenced wellbeing and learning effectiveness during the sudden transition into eLearning due to the COVID-19 lockdown

BACKGROUND

The sanitary emergency due to COVID-19 virus obliged people to face up several changes in their everyday life becauseWorld Health Organisation (WHO) guidelines and countries' Health Systems imposed lockdown of activities and social distancing to flatten the infection curve. One of these rapid changes involved students and professors that had to turn the traditional "in presence" classes into online courses facing several problems for educational delivery.

OBJECTIVES

This work aimed to investigate the factors that affected both teaching/learning effectiveness and general human comfort and wellbeing after the sudden transition from classrooms to eLearning platforms due to COVID-19 in Italy.

METHODS

A workshop, involving students and experts of Human Factors and Ergonomics, has been performed to identify aspects/factors that could influence online learning. Then, from workshop output and literature studies, a survey composed of two questionnaires (one for students and one for teachers) has been developed and spread out among Italian universities students and professors.

RESULTS

700 people answered the questionnaires. Data have been analysed and discussed to define the most important changes due to the new eLearning approach. Absence of interactions with colleagues and the necessity to use several devices were some of the aspects coming out from questionnaires.

CONCLUSIONS

The study shows an overview of factors influencing both teaching/learning effectiveness and general human comfort and wellbeing. Results could be considered as a basis for future investigation and optimization about the dependencies and correlations among identified factors and the characteristics of the products/interaction/environment during eLearning courses.

Musculoskeletal Pain, Related Factors, and Posture Profiles Among Adolescents: A Cross-Sectional Study From Turkey

PURPOSE

The aim of the study was to evaluate musculoskeletal pain due to mechanical reasons and related risk factors in adolescents and to define posture profiles of adolescents.

DESIGN

A cross-sectional study.

METHODS

The study was conducted with 2221 adolescents between February 2015 and May 2015. The questionnaire used to collect data consisted of three parts: (1) descriptive characteristics of the participants, (2) pain assessment of 14 parts of the body, and (3) Back Pain and Body Posture Evaluation Instrument (BackPEI).

RESULTS

The prevalence of low back pain among the participants was 73.3% (n = 1,343), while the prevalence of back pain was 68.4% (n = 1,254). The participants attributed their pain to their poor sitting postures at school (38.1%, n = 847) and carrying school backpacks (84.1%, n = 1,713). There was a statistically significant difference in the physical activities of adolescents and the BackPEI score (z = 4.40; p = .001). Posture factors of the BackPEI score increased while school desk comfort score increased (Spearman's rho = 0.148; p = .001), but it decreased while the school grades of the adolescents increased (Spearman's rho [ρ] = -0.161; p = .001).

CONCLUSIONS

According to this study, body posture was related to musculoskeletal pain and was correlated with physical activities, school desk comfort, and school grades of the adolescents. It is suggested that correct posture and ergonomic positions should be taught to adolescents when using computers, carrying school backpacks, and sitting in school chairs to prevent musculoskeletal pain.

School combo-desk comfort assessment: A method for weighing postural factors that affect the overall perceived comfort

BACKGROUND

In recent years, a growing interest in ergonomics and comfort perception in secondary schools and universities can be detected, to go beyond the UNI-EN regulations and understanding how practically improve students' perceived comfort during lessons.

OBJECTIVE

This study aimed to analyse the (dis)comfort perceived by students while sitting in a combo-desk during lessons; it proposed a method for understanding and weighing the influence of postural factors on overall (dis)comfort.

METHODS

Twenty healthy students performed a random combination of three different tasks in two sessions - listening, reading on a tablet and writing. Subjective perceptions were investigated through questionnaires, in which the expected and the overall comfort were evaluated; postural angles were gathered by processing photos through Kinovea® software and were used for the virtual-postural analysis, using a DHM (Digital Human Modelling) software; statistical analysis was used to investigate the influence of subjective comfort of each body part on the overall perceived comfort.

RESULTS

The statistical correlations were used to perform an optimization problem in order to create a general law to formulate the overall comfort function, for each task, as a weighted sum of the comfort perceived in each body part. The test procedure, additionally, evaluated the influence on comfort over time. The results showed how the upper back and the task-related upper limb are the most influencing factors in the overall comfort perception.

CONCLUSIONS

The paper revealed a precise and straightforward analysis method that can be easily repeated for other design applications. Obtained results can suggest to designers easy solution to re-design the combo-desk.

The efficacy of Theraband versus general active exercise in improving postural kyphosis

BACKGROUND

Thoracic kyphotic posture is accompanying increased biomechanical load of the backbone which is possibly problematic.

OBJECTIVE

The current study aimed to examine the effects of general active exercise versus Theraband exercise on female kyphotic posture.

METHODS

An experimental study was conducted at the biomechanical lab. in Physical Therapy College, Cairo University. Fourteen female volunteers with kyphotic posture aged from 18 to 30 years were selected and equally distributed into two groups; 1st group received Theraband exercises (neck retraction exercise, scapular retraction exercise, and resistive shoulder blade squeeze) and 2nd group received general active exercises (Thoracic stretching exercise, thoracic extension exercises, and extension in lying with cervical retraction exercises). Each exercise was conducted properly for 60 min in 3 sessions per week for 4 weeks (total of 12 sessions per week). The Index of kyphosis (IK) was calculated before and after treatment. Moreover, the percentage of back disability index questionnaire (PBDI) and pain score were also detected.

RESULTS

Multivariate analysis of covariance (MANCOVA) was used to compare the post-treatment's means between the first and second groups and control the pre-treatment variables. No significant differences were found post-treatment (P > 0.05). Moreover, IK measures showed a statistically significant difference post-treatment (P < 0.05). The paired sample t-test showed statistically significant differences (P < 0.05) in all variables within the first and second groups.

CONCLUSION

The current study demonstrated the positive effect of both techniques in reducing the IK, percentage of back disability index, and pain score with a more positive effect of Theraband in reducing the IK measures post-treatment.

Developing a Multi-Criteria Decision Making approach to compare types of classroom furniture considering mismatches for anthropometric measures of university students

The mismatch between students’ anthropometric measures and school furniture dimensions have been investigated in many countries. In Iran, collegians spend at least a quarter of the day hours at university in the sitting position, so it is essential to evaluate furniture mismatch among university students. In Iranian universities, the use of chairs with an attached table is widespread, while the study of mismatches in these chairs among the collegian community is rare. This study was aimed to compare and rank different classroom furniture types based on the mismatch between collegians’ anthropometric measures and the dimensions of classroom furniture among Industrial Engineering students by developing a Multi-Criteria Decision Making approach in an integrated Methodology. The sample consisted of 111 participants (71 males, 40 females). Ten anthropometric measures were gathered, together with eight furniture dimensions for four types of chairs. Mismatch analyses were carried out using mismatch equations, and the Simple Additive Weighting method was used as a base method to solve the decision-making problem. The results indicated that Underneath Desk Height and Seat to Desk Clearance showed the highest levels of the match, while Seat Width presents the highest levels of low mismatch. According to the results, Type 1 and Type 3 were the best current classroom furniture. The Sensitivity Analysis was performed in two ways: changing the weights of criteria in nine scenarios and comparing the results with five other MCDM methods. The proposed MCDM approach can be used widely in furniture procurement processes and educational environments.

Data-Driven Design Solution of a Mismatch Problem between the Specifications of the Multi-Function Console in a Jangbogo Class Submarine and the Anthropometric Dimensions of South Koreans Users

The naval multi-function console provides various types of information to the operator. It is equipment that is key for submarine navigation, and fatal human errors can occur due to the mismatch between the console specifications and the operator’s body size. This study proposes a method for deriving console specifications suitable for the body size of Korean users. The seat height, seat width, seat depth, upper edge of backrest, and worktable height were selected as the target design variables. Using six anthropometric dimensions, a mismatch equation for each target design variable was developed. Anthropometric measures of 2027 Korean males were obtained, and the optimal specifications of the console were derived via an algorithmic approach. As a result, the match rate, considering all the target design variables, was improved from 2.57% to 76.96%. In previous studies and standards, the optimal console specifications were suggested based on the anthropometric data of a specific percentile of users, and it was impossible to quantitatively confirm the suitability of the console design for the target users. However, the method used in this study calculated the match rate using the mismatch equation devised for comfortable use of the console and a large amount of anthropometric data that represented the user population, and therefore the improvement effect of the recommended specification can be directly identified when compared to the current specifications. Moreover, the methodology and results of this study could be used for deciding the specifications of multi-function consoles in several fields, including nuclear power plants or disaster situation rooms.

Architectural Indoor Analysis: A Holistic Approach to Understand the Relation of Higher Education Classrooms and Academic Performance

The influence of learning space on users has been broadly accepted and tested. However, the literature has focused on single factor research, instead of holistic approaches. Additionally, lower educational levels have been the focus of interest, while higher education is moving towards multi-method teaching. This paper focuses on how learning spaces for different purposes (practice and lecture rooms) may influence academic performance from a holistic approach of learning physical environment perception. For this, the iPEP scale (Indoor physical environment perception) is used and validated through Cronbach Alpha and Exploratory Factorial Analysis. Then, multiple linear regression is conducted. The results indicate that iPEP measures near to 63 percent of the construct, which is structured in six factors. Moreover, linear regression analyses support previous literature concerning the influence of learning physical environment on academic performance (R2 = 0.154). The differences obtained between practice and lecture room in terms of predictor variables bring to the light the need to diagnose learning environments before designing changes in educational buildings. This research provides a self-reported way to measure indoor environments, as well as evidence concerning the modern university, which desires to combine several teaching methods.

Evaluation of the guidelines and children's ability to select the anthropometrically recommendable height of school furniture: A case study of Korean primary school children

BACKGROUND

The use of school furniture with a height that is anthropometrically mismatched can lead children into taking awkward postures while sitting. In Korea, desks and chairs for primary schools have seven different height levels, and these levels are regulated by the national standard KSG-2010. These levels serve to accommodate children of all heights, but the choice problem remains because of the many alternatives.

OBJECTIVE

This study evaluates the anthropometric feasibility of the currently used guidelines for the selection of height level for Korean primary school furniture. In addition, we examine children's ability to select anthropometrically recommendable desk and seat heights.

METHODS

In study 1, anthropometric data from 2005 Korean children were acquired and a mismatch analysis was performed under the assumption that children were paired with the height level recommended by the guidelines. In study 2, we conducted a desk and seat height selection experiment that included 36 children.

RESULTS

The results of study 1 revealed that about three quarters of children could be matched by following the guidelines. The results of study 2 showed that a quarter of children selected matchable desk and seat heights by themselves. We developed new guidelines using classification algorithms based on the employed data in study 1, and it was confirmed that the new guidelines could significantly increase the degree of match.

CONCLUSION

This study confirmed that the currently used guidelines need to be revised and that children had difficulty in selecting the appropriate height of school furniture by themselves. The new guidelines suggested in this study are expected to contribute to the correct usage by Korean primary school children.

An Instrumented Workstation to Evaluate Weight-Bearing Distribution in the Sitting Posture

Background

Sitting posture may be related to risk factors, including inadequate weight-bearing support, particularly when maintained for long periods. Considering that body weight is loaded in a closed support system composed of the seat, backrest, floor and working surface, the aims of the present study were to describe the development of an ergonomic sitting workstation to continuously record weight-bearing at the seat, chair, backrest, work surface, and floor and to test its measurement properties: reproducibility, criterion-related validity, and sensitivity.

Methods

Rigid bodies (1 to 30 kg) and participant weights were recorded to evaluate the workstation measurement properties.

Results

Rigid body tests showed variation values less than 0.050 kg on reproducibility test and errors below 5% of measured value on criterion validity tests. Participant tests showed no statistically significant differences between repeated measures (p ≥ 0.40), errors were less than 2% of participant weights and sensitivity presented statistically significant changes (p = 0.007).

Conclusion

The sitting workstation proposed showed to be reliable, valid and sensitive for use in future ergonomic studies to evaluate the sitting posture.

Myoelectric Activity of Individual Lumbar Erector Spinae Muscles Variation by Differing Seat Pan Depth

Background:

The chair influences the position of the user in relation to his or her devices. Prolonged static sitting is a frequently mentioned risk factor for low back pain. Seat design, thus, plays an important role in the study of human sitting. Quantitative information is needed on what happens to body when one sits in chairs with different seat depth.

Objective:

To determine the myoelectric activity (EMG) of individual lumbar erector spinae muscles after sitting in chairs with different seat pan depth.

Methods:

EMG recordings were taken using surface electrodes placed on the lumbar erector spine muscles of 25 normal, volunteer subjects. EMG recordings for muscle activity were made while the study participants were in a comfortable position and performed the required tasks. The experiments investigated with 3 seat depths according to the 5^th, 50^th and 95^th percentiles of the buttock popliteal length. The recorded EMG data were normalized to the maximal voluntary contraction. The mean EMG recording was calculated for each of the 3 chairs tested. A mixed model was used to assess the differences among the situations.

Results:

A significant (p<0.05) difference was observed between the mean EMG recordings for the 3 tested seat pan depths. EMG activity was higher in seats with the 5^th and 95^th percentiles compared with that for the seat with 50^th percentile of buttock popliteal length depth.

Conclusion:

The seat pan depth used during a comfortable position has a significant effect on the level of myoelectric activity in the lumbar erector spinal muscles. The finding of this study may contribute to our understanding of the biomechanics of sitting.

Construction of Wood-Based Lamella for Increased Load on Seating Furniture

The research on population shows that the count of overweight people has been constantly growing. Therefore, designing and modifying utility items, e.g., furniture should be brought into focus. Indeed, furniture function and safety is associated with the weight of a user. Current processes and standards dealing with the design of seating furniture do not meet the requirements of overweight users. The research is aimed at designing flexible chairs consisting of lamellae using the finite element method (FEM). Three types of glued lamellae based on wood with different number of layers and thickness were made and subsequently, their mechanical properties were tested. Values for modulus of elasticity and modulus of rupture were used to determine stress and deformation applying the FEM method for modelling flexible chairs. In this research, the methodology for evaluating the ultimate state of flexible chairs used to analyse deformation and stability was defined. The analysis confirms that several designed constructions meet the requirements of actual standards (valid for the weight of a user up to 110 kg) but fail to meet the requirements for weight gain of a population.

Classroom Furniture Mismatch and Back Pain Among Adolescent School-Children in Abha City, Southwestern Saudi Arabia

Objective: To explore the potential classroom furniture mismatch with students’ anthropometric measurements and back pain related to sitting for extended periods. Methods: This cross-sectional study was carried out on all twelve male and female intermediate and secondary schools located in Abha city. Anthropometric and classroom furniture measurements were assessed, and the mismatch was determined using standardized methods. Students were also screened for back pain related to long sitting at school. Results: A total number of 879 students was selected. The study revealed seat height mismatch in both intermediate, and secondary school of 84.3%, and 75.6%, respectively. Seat depth mismatch was 74.0% in intermediate schools and reached 84.5% in secondary schools. The desk height was improper for 94.1%, and 82.3% of students in intermediate, and secondary schools, respectively. The levels of mismatch differ significantly by grade level and gender. A prevalence of 10.8% of back pain related to long sitting at school was found. In multivariable logistic regression, males, intermediate school children, and the presence of buttock-popliteal length/seat depth mismatch were significantly associated with pain. On the other hand, practicing exercise was a significant protective factor. Conclusions: There is a prevalent mismatch between students’ dimensions and existing schools’ furniture. School furniture providers should take in consideration the average Saudi students’ dimensions, while designing school furniture especially for males, and at intermediate schools, or provide schools with adjustable seats and desks.

A study of classroom seat (dis)comfort: Relationships between body movements, center of pressure on the seat, and lower limbs' sensations

The aim of this work is to define a new method that helps researchers to analyze perceptions of (dis)comfort in dynamic conditions. Recent studies pay considerable attention to body movements, mobility, and stability to measure comfort or discomfort when seated. Most of these discuss the relations between subjective comfort/discomfort and objective measurements (e.g. body pressure distribution, body movement and EMG) for short- and medium-term sitting. The present analysis took place in a classroom of the Industrial Engineering Department at the University of Salerno. The participants included 25 students (12 females and 13 males), who were observed during classroom hours. The students were invited to sit at a combo-desk and were free to perform different combinations of movements while writing and listening. These activities required that they adapt their body movements, as the combo-desk was fixed to the floor. A pressure pad was used to detect pressure at interface and center of pressure's changes, allowing for the bodies' motion data to be recorded. The aim was to identify the correct threshold to be used for movement detection and to investigate correlations between the number of movements and the perceived (dis)comfort. The study also identifies those body parts that have the greatest effect on (dis)comfort perception.

Determining optimum seat depth using comfort and discomfort assessments

The aim of this study was to determine optimum seat depth using subjective assessments. Comfort and discomfort evaluation, as an ergonomic subjective method, was used to find the optimum seat depth. A total of 36 university students rated the comfort and discomfort of six different seat depths (including 32.0, 37.0, 42.0, 47.0 and 52.0 cm which covered the buttock-popliteal length [BPL] range as well as 40.2 cm representing the 5th percentile of the BPL) during a 90-min period using a chair evaluation checklist. The results showed that a seat depth of 40.2 cm (equivalent to the 5th percentile of the BPL) was more comfortable and caused less discomfort ratings after 90 min compared to other experimental seat depths. The findings suggest that an appropriate seat depth for the studied population can be recommended based on the 5th percentile of the BPL as an anthropometric criterion.

A literature review of anthropometric studies of school students for ergonomics purposes: Are accuracy, precision and reliability being considered?

BACKGROUND

Despite offering many benefits, direct manual anthropometric measurement method can be problematic due to their vulnerability to measurement errors.

OBJECTIVE

The purpose of this literature review was to determine, whether or not the currently published anthropometric studies of school children, related to ergonomics, mentioned or evaluated the variables precision, reliability or accuracy in the direct manual measurement method.

METHODS

Two bibliographic databases, and the bibliographic references of all the selected papers were used for finding relevant published papers in the fields considered in this study.

RESULTS

Forty-six (46) studies met the criteria previously defined for this literature review. However, only ten (10) studies mentioned at least one of the analyzed variables, and none has evaluated all of them. Only reliability was assessed by three papers. Moreover, in what regards the factors that affect precision, reliability and accuracy, the reviewed papers presented large differences. This was particularly clear in the instruments used for the measurements, which were not consistent throughout the studies. Additionally, it was also clear that there was a lack of information regarding the evaluators' training and procedures for anthropometric data collection, which are assumed to be the most important issues that affect precision, reliability and accuracy.

CONCLUSIONS

Based on the review of the literature, it was possible to conclude that the considered anthropometric studies had not focused their attention to the analysis of precision, reliability and accuracy of the manual measurement methods. Hence, and with the aim of avoiding measurement errors and misleading data, anthropometric studies should put more efforts and care on testing measurement error and defining the procedures used to collect anthropometric data.

Ergonomic considerations for designing truck drivers' seats: The case of Bangladesh

Objectives:

The purpose of this work was to investigate the fitness of the existing truck seats for Bangladeshi truck drivers and suggest a guideline for drivers' seats based on their anthropometry.

Methodology:

In this study, eight anthropometric measurements of 120 Bangladeshi truck drivers and seven seat dimensions of ninety trucks of three brands namely, TATA, ASHOK LEYLAND, and ISUZU were considered for investigating the considerable mismatch between seat dimensions and drivers' anthropometry. The data were analyzed using two-sample t-tests to identify the relationship between existing seat dimensions and drivers' anthropometry.

Results:

The results showed a mismatch in seat dimensions and anthropometric measurements for nearly all truck brands and the existing seat dimensions were found to be inappropriate for Bangladeshi drivers. For all the truck brands, the percentage mismatch of seat height, seat depth, seat width, backrest height, and steering wheel clearance varied between 71% and 98%, 23% and 79%, 33% and 84%, 28% and 65%, and 53% and 100% respectively. Subsequently, an attempt was made to provide ergonomically correct seat dimensions for Bangladeshi truck drivers. Further, generalized equations to design the appropriate seat dimensions were developed using the least square regression technique. The recommended seat height, depth and width, backrest height, and steering wheel clearance were found to be appropriate for 82%, 79%, 76%, 98%, and 100% of drivers respectively.

Conclusion:

The analysis and results of this study can be useful in developing guidelines for design and manufacture of truck driver seats in Bangladesh.

Evaluation of the Indonesian National Standard for elementary school furniture based on children's anthropometry

In Indonesia, National Standardization Agency of Indonesia issued the Indonesian National Standard SNI 12-1015-1989 and SNI 12-1016-1989 to define the type of furniture dimensions that should be used by children in the elementary school level. This study aims to examine whether the current national standards for elementary school furniture dimensions issued by National Standardization Agency of Indonesia match the up-to-date Indonesian children's anthropometry. Two types of school furniture, small type (Type I, for grade 1-3) and large type (Type II, for grade 4-6), were evaluated in terms of seat height, seat depth, seat width and backrest height of a chair as well as the height and underneath height of a desk. 1146 students aged between 6 and 12 years old participated in the study. Seven anthropometric measurements were taken including stature, sitting shoulder height, sitting elbow height, popliteal height, buttock-popliteal length, knee height and hip breadth. Based on the standard school furniture dimensions and students' body dimensions, numbers of matches and mismatches between them were computed. Results indicated a substantial degree of mismatch between children's anthropometry and the standard dimensions of school furniture. The standard seat height was not appropriate for students among different grades with the mismatch percentage ranging from 63.4% to 96.7% for Type I and 72.7% to 99.0% for Type II. For desk height, the standard dimensions were not appropriate for students among different grades with the mismatch percentage ranging from 32.3% to 88.9% for Type I and 67.7% to 99.0% for Type II. Apparently, the current standards are out of date and need to be updated. Four different sizes of school furniture were hence proposed to accommodate the variation in students' anthropometry from Grade 1 to Grade 6. The proposed standard dimensions (PrS) of school furniture cover a slightly broader range of age and present a higher cumulative fit than the current standard dimensions (CrS). In addition, a better strategy for sizing can be also developed to fit chairs and desks to a larger number of students.

A novel method for quanitifying comfort in child passengers demonstrates an association between child restraint comfort and errors in use of booster seats

OBJECTIVE

Misuse of child restraint systems is a widespread and long-standing problem impacting risk of injury and death in car crashes. Discomfort has been suggested as a causative factor for misuse, particularly in errors introduced by children while they use the restraints. However, the relationship between comfort and errors in use has never been studied. In this study we examine the reliability and sensitivity of a newly developed observational method for assessing comfort in children in vehicles. We then use this method to examine the relationship between comfort and errors in use of booster seats.

METHODS

A novel method was developed for assessing comfort by counting fidgeting and postural adjustment behaviors to derive a Discomfort Avoidance Behavior (DAB) score. The sensitivity of the DAB score was examined by observing children in four different seating conditions designed as "comfortable" and "uncomfortable" (Part 1). Paired-samples t-tests were used to compare differences in DAB between seating conditions. The reliability of the DAB score was assessed by calculating the intraclass correlation coefficient (ICC) between DAB scores recorded by different researchers. The association between comfort and correctness of use was examined by observing children using booster seats (Part 2). The association between DAB score and number of usage errors was tested using linear regression analysis. Participants were children ages 4-8 years. Fourteen children participated in Part 1 and 15 children in Part 2.

RESULTS

The DAB score was sensitive to changes in seat condition (p < 0.01), and was repeatable between different researchers (ICC 0.98, 95% confidence interval [CI] 0.954-0.991). Increases in DAB were associated with increases in the number of use errors among children using booster seats (errors in use = 3.89 × DAB - 2.18, p < 0.0001).

CONCLUSION

The DAB score is a reliable and valid measure of comfort of children in child restraints but could be improved by incorporating a measurement of postural positioning. Comfort, as characterized by fidgeting and postural adjustment behaviors, is associated with correct use of child restraints. The broader implication is that this confirms ergonomic design of child restraints as important for minimizing errors in use. There is a need for further study of the impact of specific restraint design features on comfort experienced by children.

The effects of forearm support and shoulder posture on upper trapezius and anterior deltoid activity

[Purpose] To assess the effects of forearm support and shoulder posture on upper trapezius and anterior deltoid activity. [Subjects and Methods] Twenty-three female university students were evaluated. Muscle activity was assessed by a portable surface electromyography (sEMG) system (Myomonitor IV, Delsys, USA). Upper trapezius and anterior deltoid activity were recorded in five shoulder flexion postures: 0°, 15°, 30°, 45° and 60° and in two conditions: with the forearm supported and unsupported. Descriptive data analysis was performed and statistical analysis was conducted by a multivariate analysis of variance with three repeated factors (posture, support and side). [Results] Three-way interactions were not significant. Two-way interaction was significant for support and posture for both muscles, indicating that the muscular activity depends on the forearm support and shoulder posture. The forearm support reduced upper trapezius and anterior deltoid activity for all shoulder flexion angles. The mean and standard deviation for this decrease was 7.8 (SD=4.6)% of the maximal voluntary contraction for anterior deltoid and 3.8 (SD=2.0)% of the maximal voluntary contraction for upper trapezius. In the unsupported condition, increasing the shoulder flexion angle caused an increase in the upper trapezius and anterior deltoid activation. [Conclusion] These results highlight the importance of using forearm support and to maintain neutral shoulder posture, when the upper arms are not supported, to reduce muscle activation. Thus, this study provides evidence about the effect of these recommendations to reduce muscular activity.

The influence of school furniture on students' performance and physical responses: results of a systematic review

The purpose of this study was to determine, using a systematic review, whether the design and/or dimensions of school furniture affect the students' physical responses and/or their performance. Of the review studies, 64% presented positive results, i.e. proven effects; 24% presented negative effects or no change/effect; and the remaining 12% showed an unclear effect. The compatibility between school furniture dimensions and students' anthropometric characteristics was identified as a key factor for improving some students' physical responses. Design characteristics such as high furniture, sit-stand furniture, and tilt tables and seats also present positive effects. Finally, we concluded that further research should be conducted exploring various aspects of those variables, particularly focusing on more objective measures complemented by controlled and prospective design. Practitioner Summary: A systematic review of the literature presents a clearly positive effect of school furniture dimensions on students' performance and physical responses. Similar results appeared when school furniture design was tested. However, studying the effects of design and dimensions together produced an unclear positive effect.

Proposal for a universal measurement system for school chairs and desks for children from 6 to 10 years old

In a primary education classroom of any country, children of the same age have very different statures, reaching variations of 200 mm (Gonçalves, 2012). However, the school furniture provided is not suitable or adaptable to these differences. Designing school furniture able to respond to these variations is, therefore, a challenge for ergonomics and design in a global market. It is clearly not viable for industries to adapt productions for each country. When competitiveness and limitation of resources are essential for the viability of any product it becomes essential to find a universal system adapted to the requisites of any country. Taking as prescription measure the popliteal height obtained from the data of different countries, a universal measurement system for the school chair and desk set is proposed, combining the ellipse methodology used by Molenbroek et al. (2003) and the (mis)match equations mentioned by Castellucci et al. (2014b). From the results obtained, it can be concluded that only 5 sizes are needed to implement this new measurement system of evolutionary school furniture for the primary education classroom.

Development and validation of instrument for ergonomic evaluation of tablet arm chairs

The purpose of this study was to develop and validate an evaluation instrument for tablet arm chairs based on ergonomic requirements, focused on user perceptions and using Item Response Theory (IRT). This exploratory study involved 1,633 participants (university students and professors) in four steps: a pilot study (n=26), semantic validation (n=430), content validation (n=11) and construct validation (n=1,166). Samejima's graded response model was applied to validate the instrument. The results showed that all the steps (theoretical and practical) of the instrument's development and validation processes were successful and that the group of remaining items (n=45) had a high consistency (0.95). This instrument can be used in the furniture industry by engineers and product designers and in the purchasing process of tablet arm chairs for schools, universities and auditoriums.

Does a prototype 'Experimental' chair facilitate more postural changes in computing adolescents compared to a normal school chair?

BACKGROUND

Prolonged sitting, such as when computing, has been linked to adolescent spinal pain. A chair should fit the user's body dimensions and aid the user in frequently changing sitting posture, rather than support one 'ideal' posture. Such a chair is not currently available to high school learners.

OBJECTIVES

To develop a novel experimental school chair. To determine whether the experimental chair encourages regular small range movement in all directions whilst students work at computers in class. To compare the number of postural changes between the normal static school chair and the experimental chair, whilst students do computing work.

METHODS

A development and validation study was conducted. Twelve high school students were randomly selected from a conveniently selected school. Fifteen minutes of 3D posture measurements were collected in both the prototype and school computer chair. The analysis focused on the frequency of postural movement.

RESULTS

Data of eleven learners were analysed. There were statistically significant increases in the number of postural changes on the 'Experimental' chair compared to the school chair, for both pelvic side-flexion and pelvic rotation (ρ= 0.01).

CONCLUSION

The experimental chair provided more postural movements when compared to the school computer chair. Future studies should use this experimental chair to determine the effect of increased postural movement, of especially the pelvis, on the prevalence and intensity of musculoskeletal symptoms of high school learners in the Cape Metropole area, Western Cape, South Africa.

Static Anthropometric Characteristics of Bangladeshi Vehicle Driver: A Case Study

Background. Inappropriate design of sitting furniture and working equipment causes the serious musculoskeletal injuries and various pains as well as reducing working efficiency. Uncomfortable sitting posture in prolonged driving in Bangladesh is an issue to be solved immediately. Therefore, anthropometric databank of user population is significantly essential for the suitable dimensional design for avoiding these remarkable problems. Methods. This study analyses the anthropometric data of the Bangladeshi male vehicle driver aged between 30 and 60 years. A total of 210 Bangladeshi healthy drivers are considered for 15 anthropometric measurements and compared with the similar anthropometrics of other nationalities. Results. The mean stature and sitting height erect of Bangladeshi driver are 1645 mm and 843 mm, respectively. The mean of body mass index (BMI) of the drivers is 26.09 kg/m(2), which indicates that the drivers are overweight. The mean stature of Bangladeshi driver is 17 mm shorter than the driver of Korea and 115 mm shorter than the driver of Iran. Conclusion. There are substantial differences between the body dimensions of Bangladeshi driver and similar dimensions of other countries. In comparison, Bangladeshi driver is found to be the shortest compared with the sample of other nationalities.

Evaluation of the match between anthropometric measures and school furniture dimensions in Chile

BACKGROUND

Students are exposed to the first systematic tasks or activities that a human being carries out in his/her life while at school. In this workplace situation, school furniture is a key factor for the adoption of proper body posture.

OBJECTIVE

The aim of this paper was to observe and determine the potential mismatch between school furniture dimensions and anthropometric characteristics of the students from the Valparaíso region of Chile.

METHODS

The sample consisted of 3,078 volunteer participants from 18 schools (public, semi-public, private). Eight anthropometric measures were gathered, together with six furniture dimensions. Mismatch analyses were carried out by using pre-defined mismatch criteria.

RESULTS

Many different types of school furniture were presented at the schools. Also, a high level of mismatch was registered for seat height, desk height and seat-to-desk clearance. Finally, the analysis of all considered dimensions together showed that there was a high level of cumulative mismatch.

CONCLUSIONS

It can be concluded that there were high levels of mismatch between the school furniture and student anthropometric characteristics and that this mismatch varied within the difference types of schools. This situation may have occurred because furniture acquisition was made without considering any ergonomic criteria.

Anthropometry of Iranian Guidance School Students with Different Ethnicities: A Comparative Study

Objective. We measured some anthropometric dimensions of Iranian guidance school students selected from different ethnicities. Background. Anthropometric dimensions are used for design of equipment, furniture, and clothing. Furniture with inappropriate design not fulfilling the users' anthropometric dimensions may have a negative effect on health. Method. A total of 7400 Iranian guidance school students aged 12-14 years entered the study and their static anthropometric dimensions were measured. Descriptive statistics such as mean, standard deviation, and key percentiles were calculated. All dimensions were compared among different ethnicities and different genders. Results. This study showed significant differences in a set of 22 anthropometric dimensions regarding gender, age, and ethnicity. Conclusion. According to the results of this study, difference between genders and among different ethnicities should be taken into account by designers and manufacturers of guidance school furniture. Application. This study has prepared a data bank of anthropometric dimensions of 12-14-year-old students which can be used as basic information to find appropriate dimensions of school furniture.

Effect of Cognitive Load on Seating Posture in Children

Although children are frequently required to sit upright, it is often difficult to maintain this posture when performing cognitive tasks. Information about the relationship between a cognitive tasks and postural seating control is important for children to complete tasks more effectively. To determine the muscle activity and body sway of children in a seated posture while performing a cognitive task, changes in muscle activity and center of pressure (COP) were recorded while 4(th) grade children performed arithmetic tasks. Electromyography was recorded from the internal oblique and lumbar multifidus muscles, and the COP was recorded using a baropodometer placed on the stool. These variables were measured during easy (EA) and difficult (DA) arithmetic tasks. EMG activity decreased during the EA and DA tasks, while the COP was displaced in the DA task. The results of the arithmetic tasks were not related to the EMG or COP changes. Attention to maintain a seated posture may be reduced when children perform cognitive tasks. Therefore, it may be better to allow children to alter their posture especially when they are performing difficult tasks. In this research, we only used arithmetic tasks as the cognitive exercise, and therefore, other types of tasks should be examined.

Static anthropometric dimensions in a population of Iranian high school students: considering ethnic differences

BACKGROUND

Anthropometric dimensions of the end users should be measured in order to create a basis for manufacturing of different products. This study was designed to measure some static anthropometric dimensions in Iranian high school students, considering ethnic differences.

METHOD

Nineteen static anthropometric dimensions of high school students were measured and compared among different Iranian ethnicities (Fars, Turk, Kurd, Lor, Baluch, and Arab) and different genders.

RESULTS

In this study, 9,476 subjects (4,703 boys and 4,773 girls) ages 15 to 18 years in six ethnicities were assessed. The difference among ethnicities was statistically significant for all dimensions (p values < .001 for each dimension).

CONCLUSION

This study showed statistically significant differences in 19 static anthropometric dimensions among high school students regarding gender, age, and ethnicity.

Match between classroom dimensions and students' anthropometry: re-equipment according to European educational furniture standard

OBJECTIVE

The aim of this study was to investigate mismatch between students and classroom furniture dimensions and evaluate the improvement in implementing the European furniture standard.

BACKGROUND

In Portugal, school furniture does not meet any national ergonomic criteria, so it cannot fit students' anthropometric measures.

METHOD

A total of 893 students belonging to third (7th through 9th grades) and secondary (10th through 12th grades) cycles participated in the study. Anthropometric measurements of the students were gathered in several physical education classes. The furniture dimensions were measured for two models of tables and seats. Several two-way equations for match criteria based on published studies were applied to data.

RESULTS

The percentage of students who match with classroom furniture dimensions is low (24% and 44% between table and students, 4% and 9% between seat and students at 7th and 12th grades, respectively). Table is high for the third cycle, seat is high for both cycles, and seat depth fits well to students. No significant relationship was found between ergonomic mismatch and prevalence of pain.

CONCLUSION

For each cycle, at least two different sizes indicated in the European standard should be available to students, considering the large variability in body dimensions within each cycle. The match criteria used gives a large percentage of students without pain in a mismatch situation.

APPLICATION

Future measures applying to secondary schools should revise the decision of selecting a single size of classroom furniture and improve the implementation of the European standard. New criteria for ergonomic mismatch are needed that more closely model the responses about discomfort/pain.

Analysis of the most relevant anthropometric dimensions for school furniture selection based on a study with students from one Chilean region

Most of the worldwide standards used for furniture selection suggest the use of the Stature of the school children, assuming that all the other anthropometric characteristics will also be appropriate. However, it is important to consider that students' growth differ with age. The aim of this study is to determine if Popliteal Height can be used as a better, or more adequate, measure for classroom furniture selection when comparing with Stature. This study involved a representative group of 3046 students from the Valparaíso Region, in Chile. Regarding the methodology, eight anthropometric measures were gathered, as well as six furniture dimensions from the Chilean standard. After assigning the level of school furniture using Stature and Popliteal Height to each of the students, six mismatch equations were applied. The results show that when using Popliteal Height, higher levels of match were obtained for the two more important furniture dimensions. Additionally, it also presents a better cumulative fit than Stature. In conclusion, it seems that Popliteal Height can be the most accurate anthropometric measure for classroom furniture selection purposes.