Journal of Ergonomics

Abstract

Introduction

The extensive development of written interactions in the current world of technology in one hand, and on the other hand noticeable dominance of English language in this milieu, has led to inadequate utilization of Farsi in such settings, even amongst native speakers. Lack of experimental data regarding legibility and readability of the printed and electronic texts related to this language has been the main theory behind the current research, which was designed to evaluate correlations between typography and reading performance.

Materials & Methods

Eighty four Farsi speaking university students, having no specific visual impairments, took part in the study. Frequently used Farsi fonts, edited in equal pixel areas and sizes, and were evaluated through legibility and readability tests. Word detection and word search techniques were considered for each test respectively. All trails were designed within similar visual interaction conditions to avoid any background biases.

Results

Statistical analyses revealed correlations between typography and readying performance in Farsi (compared to English). Amongst the six frequently used fonts studied, legibility was significantly higher in Yekan, t (83) = -2.649, p=0.012. Likewise readability was found to be significantly smoother in Zar font, t (83) = - 2.194, p=0.037.

Conclusion

On the whole, the current approach towards classification of Persian fonts confirms the outcomes of the present study. In other words, fonts frequently used for development of body of the texts usually have higher legibility, and types being utilized for presentation purposes mainly possess higher readability.

Introduction: The prevalence of work-related musculoskeletal disorders in computer users is high. The purpose of this study was to evaluate ergonomic assessment musculoskeletal disorders risk in computer users determine the effect of an eight-week corrective exercises program on reduction of musculoskeletal pain.

Material and Methods: In the first phase of the study, RULA technique and Nordic questionnaires were used to evaluate postures and musculoskeletal disorders of 84 computer users of Tuyserkan administrations. In the next phase, 30 individuals for participating in a corrective exercises program intervention divided into two groups namely, experimental (n=15) and the controls (n=15). Subjects were re-evaluated after period of eight weeks. Data was analyzed using independent and dependent t-tests.

Results: The overall prevalence of pain was seen in neck, lumbar, shoulders, back, carpal and hand, elbow respectively. In posture analysis, 61.3 and 53.6 percent of subjects were in action level of 2 in left and right limbs respectively, 32.2 and 44.1 percent of subjects were in action level of 3 and 2.4 percent in level of 4 in right side. After the corrective exercise intervention, there was 38.3% significantly reduction pain for upper limbs (p=0.001) and 38.7% for lower limbs (p=0.006).

Conclusion: This study showed that frequency of musculoskeletal problems in neck, lumbar, shoulders, back, wrist was generally high among our subjects, and selected corrective exercises could reduce the risk level and pain.

Introduction: Musculoskeletal disorders are major concerns of the modern world due to their effect on the physical health and productivity of the workforce. More extensive research is therefore required to identify and prevent these injuries and control the risk factors causing their development.

 Materials and Methods: The present study uses a theoretical model of ergonomic interventions to examine and improve ergonomic conditions in an automobile spare part manufacturing plant. A total of 44 employees were selected through simple random sampling and according to the Morgan table from the 50 personnel working at the plant. The Nordic Musculoskeletal questionnaire and the review of ergonomics tips inventory were used to identify the ergonomic risk factors. Based on the theoretical model used in the research, the ergonomic intervention was performed in two stages.

Findings: In the macro stage of the ergonomic intervention, 7 goals were set and 13 ergonomic recommendations were made in the form of several workshops and task forces. In the micro stage of the ergonomic intervention, 20 ergonomic risk factors were identified and 13 strategies and plans were suggested. With the senior manager's approval, 11 strategies entered the implementation stage with the aim of improving ergonomic conditions and increasing productivity at the workplace.

Conclusion: The main outcome of the comprehensive ergonomic interventions performed in the present study was a modified organizational culture, entailing both direct and indirect benefits, such as providing low-cost or no-cost solutions to the problems, creating an active environment of continuous improvement, increasing employees' motivation for participation and being innovative in solving the problems, increasing the inclination among the employees to be an innovative thinker, improving communication between the authorities and the personnel and increasing the employees' general knowledge and capabilities.

Introduction: An important measure for ensuring safety in the operation of industrial machinery is to install proper guards that prevent machine hazards and protect operators. The design of industrial machine guards is a key issue in ergonomics and worker safety and has become a focus of research in hand anthropometry.

The present study was conducted to assess the different hand anthropometric dimensions of employees in an industrial unit and to design a fixed mesh guard in the shape of a rectangle for industrial machines and to use the collected data for the standardization of industrial machine guards in Iran to help prevent machine hazards.

Materials and methods: Thirteen right hand anthropometric dimensions of 97 male and female employees of an industrial unit were examined. To design a standard fixed guard, the length dimensions of the 99th percentile of men and the thickness (diameter) and width of the 1st percentile of women were calculated.

Results: According to the data obtained, a standard fixed guard creates a safe distance of 196.61 mm with the hazardous components of the machine, a gap length of 10.19 mm and a gap width of 8.29 mm. Comparison of 6 parameters, including DIP, PIP, MCP, TE, DPC and WR, with the OSHA regulations showed that PIP and WR had decreased, MCP, DIP and TE had increased and DPC could not be analyzed given the lack of sufficient information on the parameter in the OSHA.

Conclusion: The design of machine guards that help prevent industrial hazards is an integral part of workplace safety. The analysis of DIP, PIP, MCP, TE, DPC and WR in the present study and in a study conducted by Vaillancourt et al. showed some of the parameters to have increased and some to have decreased compared with the OSHA regulations. This study also reveals the need for revising ISIRI 11800, a standard published by the Institute of Standards and Industrial Research of Iran.

Introduction: Musculoskeletal disorders are among the top 10 injuries accounting for absence from work. The Extended Nordic Musculoskeletal Questionnaire (NMQ-E) is one of the many tools used to examine these disorders. The present study was conducted to translate and localize the NMQ-E and to evaluate the face validity and test-retest reliability of its Persian version.

Materials and Methods: The present non-empirical methodological study used the International Quality Of Life Assessment (IQOLA) approach to translate the NMQ-E into Persian. The face validity of the Persian version was examined in a sample of 15 patients with musculoskeletal disorders (MSDs) and its absolute and relative test-retest reliability were examined in a sample of 48 patients using the Standard Error of Measurement (SEM) and the Intra-class Correlation Coefficient (ICC). The Kappa coefficient was also used to measure the inter-rater agreement for nominal variables.

Results: The translation and localization of the NMQ-E was deemed easy and acceptable. All the items of the questionnaire had an acceptable face validity. The Intra-class Correlation Coefficient and the Standard Error of Measurement of the Persian version of the NMQ-E were deemed acceptable (SEM=0.56-1.76 and ICC>0.7) and the Kappa coefficient was calculated as 0.78-1.00. 

Conclusion: The Persian version of the Extended Nordic Musculoskeletal Questionnaire showed an acceptable validity and test-retest reliability for assessing musculoskeletal disorders in Iranian patients.

Introduction: Introduction: Inappropriate sizes of school furniture and the deformation of children’s bodies is one of the issues of concern in the world. The aim of this study was the evaluation of anthropometry of primary students aged 6-12 years in Mazandaran, Iran and the design of school furniture based on the anthropometric criteria of the students.

Methods: In this cross-sectional study, 18 anthropometric dimensions of 2336 boys and girls aged 6-12 years in 2014-2015 were measured. To collect data, anthropometric chair, camera and camera stand, and Anthropometric photo graphical software were used. After determining the anthropometric dimensions, ergonomic school furniture was designed.

Results: Average, minimum, maximum, standard deviation, median and percentile value of 2.5 to 97.5 of the anthropometric dimensions of students were calculated. The results showed that gender had no effect on the popliteal height in the age groups of 6 to 7 and 7 to 8, but age had effects on popliteal height (P < 0.001). In the age groups of 8 to 9 and 9 to 10 years and also the age groups of 10 to 11 and 11 to 12 years both gender and age had effects on popliteal height (P < 0.001).

Conclusions: The results showed that by eliminating the effects of gender, 16.2 mm popliteal height increased per year. It was also found that after eliminating the effects of age, popliteal height increased 20.39 mm more in girls than in boys. Until the age of puberty, the anthropometric dimensions in girls increased more than in boys. The dimensions of ergonomics tables and chairs for students were designed in three sizes.

Introduction: The importance of product design has been dramatically increased in recent years due to economic considerations as well as changes in user preferences, policy making and legal needs. In response to this, and as one of the most influential branches in the field of product design (in terms of the fit between product and user), ergonomics has also been developed proportionally. The aim of this study was to review the most important considerations and different traditional and new approaches in product design as well as challenges and limitations in this regard.

Methods: A review was made of the relevant electronic databases including Ergonomics Abstracts, PubMed/Medline, Web of Science, Science Direct, Scopus and Google Scholar using the following keywords: product, design, ergonomic, design procedures and design approach. The search was limited to full text articles in the English language, published in peer reviewed journals between 1990 and 2015.

Results: Comparison of the traditional and new approaches in product design indicated that the new approaches helped designers to choose the best product model based on various aspects and a more detailed interaction between user and product. Ergonomic considerations in product design also include engineering and psychological aspects as well as taking into account abilities and limitations of both products and users, to find a good fit between user and product.

Conclusions: The findings suggest that the traditional approaches in product design alone may not anymore guarantee the success of a product in the market, particularly in universal scale and for a wide range of users. In other words, consideration of various technical (in terms of user-product interaction) and legal (environment, sustainability, cost benefit, etc.) aspects in new ergonomic approaches may be taken into account to improve the quality and success of the products in the global market. Ergonomists may encounter with some challenges to achieve this goal, but high-quality ergonomics services can be considered as an effective solution in this regard.

Introduction: According to the effectiveness and low cost of prevention, ergonomic assessment methods as a means to predict the potential occurrence of injury are being used. The aim of the present research was the assessment of validity and reliability of researcher-made ergonomic assessment test for freestyle wrestling skills.

Methods: In this research, according to the jobs ergonomic evaluation tests and wrestling pathology research, an ergonomic evaluation test for wrestling skills (WSEAtest) was designed. Content and face validity were proved by using the opinions of sports biomechanics and pathology experts, as well as physicians, physiotherapists, trainers and wrestlers of Freestyle national team. Furthermore, the test was performed on three skills in two different days by five examiners, using Kinovea software 0.8.15; also, intra- and inter-tester reliability were calculated. After the reliability and validity approval, WSEAtest was performed on video records of four selected skills of Iranian freestyle wrestlers in London 2012 Olympic games.

Results: The injury exposure in various parts of body, traumatic factors related to collisions and loads, and athlete and environment conditions were consistent with wrestling pathological research and confirmed the validity of the test results.

Conclusions: WSEAtest has acceptable validity and reliability; trainers, specialists, and sports therapists can use this test to assess traumatic factors and identify priorities for training and corrective exercises in different wrestling levels, and in various ages.

Introduction: Advances in technology and the use of complex systems at work have imposed high mental workloads to operators; so, continuous monitoring of mental workload can help to prevent mental problems and maintain mental health. Therefore, this study aimed to investigate the impact of mental workload on physiological and subjective responses.

Methods: This cross-sectional descriptive-analytical study was performed on 16 healthy university students in 2014 at a laboratory setting. Physiological parameters of surface electromyography and electrocardiography in six blocks (resting, high mental work, moderate, low, very low and recovery) were measured using NeXus-4. After performing each block, the NASA-TLX questionnaire was completed. Statistical analysis was conducted using SPSS software version 21.0. A 5% significance level was adopted in all the tests.

Results: The results showed significant differences for the average score of NASA-TLX between the different levels of mental work load (P < 0.05). Also, the analysis of repeated measures variance showed significant differences for heart rate and heart rate variability parameters in the six blocks (P < 0.05), but no significant difference was observed for the shoulder muscles activity.

Conclusions: Different levels of mental work load can impact on people's subjective responses and some of their physiological responses. Thus, in such workplaces, it will be necessary to conduct an ergonomic program to manage mental health.

Introduction: the quality of life of nurses and nurse aides is under the influence of various factors including the occupational ones, which affect the quality of their services. The purpose of this research was to investigate the occupational and demographic factors effective on the quality of life of nurses and nurse aides working in teaching hospitals affiliated to Kerman University of Medical Sciences.

Methods: the present research was a cross-sectional one conducted in 2014 on 620 nurses and nurse aides. Simple random sampling method was utilized. The data were collected via the World Health Organization Quality of Life short form (questionnaire). Shift working, having a second job, marital status, length of marriage and having a shift working spouse were the independent variables of this study. Data were analyzed in SPSS 18 software using analysis of variance (ANOVA), Pearson’s correlation coefficient, independent t and linear regression statistical tests.

Results: the average age, length of marriage and work experience in hospital were 32.81 ± 7.84, 10.61 ± 7.30 and 10.29 ± 7.68, respectively. The number of children, having a second job, satisfaction from the hours spent with family, and belief in the effect of night work on family life were factors effective on quality of life (P > 0.05). The highest relationship of quality of life was with environmental health (r = 0.87, P = 0.001) and the lowest was with social health (r = 0.75, P = 0.002).

Conclusions: Avoiding to have a second job, scientific planning of shift work schedules and trainings relevant to life skills in shift workers would help improve the quality of life of nurses and nurse aides.

Introduction: Varicose veins in the lower limbs commonly occur in the general population and can negatively affect their quality of life. One of the high-risk jobs is the field hairdressers. The aim of this study was to investigate the effects of ergonomic interventions on quality of life of female hairdressers suffering from diseases in the lower extremities varicose veins.

Methods: The study population was all female hairdressers of Hamadan Mahdieh clinic who were referred for medical examinations. Using simple random sampling method, 70 patients suffering from varicose disease were chosen and were classified to case and control groups. The intervention included an exercise protocol for the cases with varicose disease. The present study was quasi-experimental with pre-test and post-test and participants responded to Aberdeen varicose veins, chronic pain and muscle fatigue questionnaires, which were considered as indicators of quality of working life. Data was analyzed by paired sample t-test using of SPSS 16.

Results: The results showed that ergonomic interventions were effective on the rate of varicose score, pain and swelling score as well as the score of muscle fatigue of left and right lower limbs in the case group. The average scores of varicose veins, pain and swelling, and left and right lower extremity muscle fatigue in the case group decreased respectively 2.66, 2.4, 0.75 and 1.2.

Conclusions: With regard to the impact of exercise protocol on quality of working life in hairdresserd, the use of this protocol is recommended in patients with varicose veins disease.

Introduction: Nine percent of all available packaging are jars with steel lids. However, some consumers have trouble with jar opening. The aim of the current research was to analyze the exerting force on jar lids regarding the torque input to the anthropometric and physiological characteristics of the consumers.

Methods: In this study, the force distributed on the fingers and the palm was examined using a special tester consisting of Force Sensing Resistors (FSR). This tester included 19 sensors, 14 of which were installed on the fingers and 5 on the palm. Each sensor was connected to a driver via 2 wires and then to a computer by a USB port. A full jar with 1100 g weight and 85 mm lid outer diameter was used and the forces exerted by 20 participants, including 10 male and 10 female students, was recorded. Next, the Minitab 17 software was used and the mathematical relationship between the torque and anthropometric and physiological characteristics was investigated.

Results: It was found that the force is mainly exerted by the index finger. The calculation of the torque based on the force measurements showed that the maximum torque applied by males was 10.63 Nm and by females was 7.66 Nm. Statistical F test for the torque (response variable) at a significance level of 0.05 resulted in P values equal to 0.011 and 0.008 for male and female participants, respectively. Therefore, it can be concluded that the measured values are statistically significant.

Conclusions: Statistical analysis revealed that hand dimensions and grip strength play major roles in applying torque. Additionally, the results indicated that packaging conditions for the particular jar in this study must be adjusted such that the consumers with the lowest physical ability (5.11 Nm torque) could open them.

Introduction: Content analysis is amongst common methods of scientific research of journals. According to the paucity of such studies in the ergonomics scope and the need for information on the direction and characteristics of conducted research and in order to gain more detailed plans, this study aimed to perform a content analysis of scientific outputs regarding occupational Health with an emphasis on ergonomics.

Methods: This cross-sectional study was conducted on articles published by Persian and interior Latin journals with a minimum track record of 3 years for a period of 10 years, from 2005 to 2015. Data were collected via a researcher-made checklist, using census and based on the content analysis method.

Results: The extracted data, from 927 articles during the period of 10 years, from 5 specialized journals, showed that the largest share of researches was related to the ergonomics scope (24.27%). The main research tools used in ergonomics articles were questionnaires (69.77%). Based on the types of studies, only 15.55% of ergonomic researches were based on interventional studies.

Conclusions: Articles with the subject of ergonomics have increased over the past decade. Most research has been conducted with an emphasis on physical health; however, psychological and social aspects of health have been somewhat neglected. Most research in ergonomics scope was descriptive, analytical, and cross-sectional. In this regard, more attention should be paid to interventional studies.

Introduction: Muscle-skeletal disorders are one of the most common job-related disorders in industrial workplaces due to different reasons. The current study performed an ergonomic assessment using the key indicator index (KIM) in order to reduce injuries in the bottle-making salon of one of the detergent-producing industries of Qazvin province.

Methods: This study was an interventional study and consisted of 25 workers and was done in a bottle-making salon of one of the detergent-producing industries, during year 2016. For data collection, the Cornell questionnaire and key indicator index assessment method were used before and after the ergonomic interventions. Data was analyzed by descriptive analytical tests using the SPSS 16 software.

Results: According to the results, in the bottle production task (risk score: 4), the risk score decreased significantly by redesign (risk score: 2). Also, regarding the bottle's material, supply task that workers used to do it by manual material handling (risk score: 3), by redesign, risk score decreased significantly (risk score: 1).

Conclusions: In this study, musculoskeletal disorders decreased meaningfully by workstation ergonomic redesign after 5 months from the intervention.

Introduction: The working population spends an increasing amount of waking times at work that is full of social relationship and meaningful resource of social capital. With regard to relationship between workplace social capital and employee health, this systematic review was performed with aim to evaluate the effects of workplace social capital in health workforce.

Materials & Methods: This is a systematic review study. The articles were in full text and  in English language that were cited in Pubmed, Scopus, and Google scholar database with key words such as "workplace social capital" ,"health", "hypertension", "diabetes", "depression" without time limit were selected, at least 14 articles were eligible.

Results: Workplace social capital was related with cardio-vascular disease, hypertension, diabetes and depression among the employees.

Conclusions: Workplace social capital should be considered as one of the most important issue in health promotion.