Iranian Journal of Ergonomics

Introduction: work engagement is a stable and positive state of mind associated with work, which protects against job burnout. This study was conducted to determine the contribution of goal orientation, perceived organizational support and Big Five personality traits in predicting job motivation of female teachers in Shahrekord, Iran.

Methods: The design of the study was correlational-survey. The sample included 230 female teachers in Shahrekord, teaching in high school during 2013-2014. The sample of the study was selected by cluster sampling. To collect data, goal-orientation, perceived organizational support, five factor inventory and job work engagement were administered to the participants.

Results: Correlation and step regression analyses were utilized to analyze the data. Findings of the study showed that there was a significant relationship among goal-orientation, perceived organizational support, Big Five personality traits and work engagement (P < 0.01). Furthermore, multiple regression analysis revealed that linear combination of goal orientation, perceived organizational support and Big Five personality traits could predict work engagement of teachers )P≤0.01).

Conclusions: the present study indicated that different components of personality, goal-orientation and perceived organizational support can create work engagement.

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 progress of technology and modern technology has changed today’s workplaces and imposed more mental and cognitive demands to workers. Control room is an example of these workplaces. Currently, assessment of mental workload is a key point in the research and development of human-machine relationships in workplaces. This study aimed to validate an analytical approach in evaluating demanded mental workloads for control room operators in Pars combined cycle power plant.

Methods: This was a fundamental-practical and cross-sectional study. First of all, a task analysis was used to understand the operation steps of control room operators. Then, the Visual, Auditory, Cognitive, Psychomotor (VACP) technique was applied to determine the mental workload demanded for performing each step of the works. Finally, the assigned ratings of the VACP method were validated by the analysis of Pearson’s correlation with the answers of the NASA-Task Load Index (NASA-TLX) questionnaire, collected from the control room operators.

Results: Based on the results, the correlation between the assigned ratings of VACP technique and the answers of the NASA-TLX questionnaire was positive and significant.

Conclusions: Due to the high correlation between the assigned ratings of VACP technique and the answers of the NASA-TLX questionnaire, the proposed VACP technique, which can be carried out in the early stage of the design, was suitable as an analysis tool for predicting metal workloads of control room operators.

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: Shift work, in addition to its effects on physical, psychological and social status, may impact on oral health. The aim of this research was to assess the relationship between shift work and oral health in nurses.

Methods: This cross-sectional study was carried out on 120 nurses working in a hospital affiliated to Tehran University of Medical Sciences during 2014-2015. Oral health status and DMFT index (Decayed, Missing and Filling Teeth) was assessed by a dentist through clinical examination. Data were analyzed using SPSS 22 software, chi-squared test, independent samples t-test and multiple logistic regressions test.

Results: The results showed that the means of DMFT index in shift work nurses and non-shift work nurses were 8.10 ± 4.10 and 9.41 ± 2.8, respectively. There was no significant difference between decayed, missing and filled teeth and periodontal DMFT index in both groups. Multiple logistic regression analysis revealed that age was a significant predictor of DMFT indictor (P<0.001). No significant relationship was found in DMFT index with gravid, parity, family income, anxiety and work experience.

Conclusions: This study demonstrated that shift work was not an independent factor affecting oral health. However, regarding the DMFT index mean differences and nurses’ job responsibilities, it seems necessary to pay more attention to this occupational group.

Introduction: Musculoskeletal disorders (MSDs) are inevitable consequences of ergonomic principles neglect. The increasing use of computer by students may result in these disorders. Therefore, the present study was conducted to determine the prevalence of MSDs and evaluate the effectiveness of ergonomics training intervention among university students.

Methods: This interventional and cross-sectional study was performed on a group of medical and paramedical students. Samples were chosen by simple sampling method. In the first stage, data were gathered by means of a self-made measurement and Nordic Musculoskeletal Questionnaire (NMQ). Furthermore, an educational booklet regarding the principles of ergonomics in computer use (educational intervention) was offered to the subjects. In the second stage of the study, the effectiveness of intervention was evaluated using a written exam and a quasi-objective structured clinical examination (quasi-OSCE) test. Data were analyzed by SPSS 15, as well as descriptive and analytical statistical indexes.

Results: From 205 students participated in the first round of the study, the results showed that 62.44% of them (128 persons) reported at least one complain or limitation in their musculoskeletal systems during the past year. Less than 10% of the participants were aware about the considerations of ergonomics principals during computer use. After submission of the educational materials, their awareness about the ergonomics considerations in computer use significantly improved(P<0.001) and more than 95% of them had good or medium performance after the intervention.

Conclusions: The training program was effective on the awareness of ergonomics principles in computer use. However, prevention of musculoskeletal disorders requires complementary measures such as elimination of risk factors and administrative controls.

Introduction: Since faculty members are among the most important assets of higher education institutions, surveying and identifying factors associated with these sources that can be effective on their performance and stress have gained increasing importance. Accordingly, the present study was conducted to survey the relationship between personal accountability and job performance considering the mediating effect of skills and job stress among employees of the University of Shiraz.

Methods: The statistical population of this study consisted of all of Shiraz University staff who had high school diploma, which included 726 individuals. A sample of 256 persons was chosen using stratified random sampling method. The research method was descriptive-correlative. Data were collected using Hochwarter et al. (2005) accountability, job performance (1990) of Paterson, House and Rizzo’s (1972) Job tension and political skills, and Ferris et al. (2005) satisfaction standard questionnaires. The structural equation modeling (SEM) was used to study the relationship between the latent variables and the measured ones in conceptual model.

Results: The results showed that job performance was affected by personal accountability; employees who had political skills had more accountability, which significantly affected their job performance. Job tension had a significant negative correlation with job performance.

Conclusions: According to the results, political skills and job tension affected the relationship of individual’s accountability with job performance. The results put emphasis on the necessity of reassessing the mediating roles of political skills and job tension in surveying the causal relationships of accountability with job performance.

Introduction: Work-related fatigue is a source of concern, even in most industrialized countries. One of the most important factors influencing an employee’s physical and mental condition is the degree to which employees are able to recover from fatigue and stress after work. Factors such as workload can cause fatigue in workers. The aim of this study was using the need for recovery scale to assess workload in mine workers and its relationship with demographics.

Methods: In this cross-sectional study, 80 workers of a mine were surveyed. The data gathering tools used in this study were demographic characteristics questionnaire and the need for recovery scale. The scale assesses the workers workload with 11 two-optioned phrases. Mean, standard deviation, and Pearson’s correlation coefficient and ANOVA tests were used in order for data analysis.

Results: Mean (SD) score of the need for recovery scale was 55.22 (23.93), indicating moderately high workload in the workers. A total of 58.7% of workers experienced high levels of workload. Among the demographics, only body weight had a significant relationship with the need for recovery score (P value = 0.043).

Conclusions: Due to the relatively high need for recovery in the study population, solutions should be employed, such as reducing the workload, use of work-rest schedules, performing heavy tasks within teams, and providing conditions for proper and enough recovery after work, which can increase health conditions of workers.

Introduction: Driving is a complex task engaging high level of cognitive and motor processes. Adding to this complexity, engagement in cognitive secondary tasks such as talking with other passengers, speaking on the cell phone or listening to radio may effect driving performance. In addition, age-related cognitive limitations may adversely challenge driving performance. As the number of elderly drivers is rising, it is important to pay more attention to this matter.

Methods: The effects of cognitive secondary tasks on driving performance were explored through two on-road experiments (with and without listening to a recorded dialogue). In this study thirty-two individuals (male, M = 72.6, SD = 5.43) voluntarily took part in the experiments. The mean driving speed, duration of driving in unsafe-zones, numbers of overtaking, and deviation of lateral lane position were recorded, adopting a radar system and video camera. After determination of the normality of data, paired t test and correlation analysis were conducted.

Results: Mean driving speed (P < 0.05), duration of driving in an unsafe zone (P < 0.05), and numbers of overtaking (P < 0.001) showed considerable reduction of participants’ engagement in listening to the recorded dialogue. In contrast, mean deviation of lateral lane position increased.

Conclusions: The findings revealed that driving performance of elderly drivers was effected when listening to a recorded dialogue. However, in order to increase driving safety, they adopted some compensating strategies.

Introduction: Pilot performance investigation during multi-tasking operations requires a procedure, in which the parameters related to the desired scenario of the simulator are obtained in a systematic manner. The multi-attribute task battery (MATB-II) is a standard simulator of generic piloting tasks developed by national aeronautics and space administration (NASA).

Methods: Employing information theory concepts, baud rate generated in all subsystems of the MATB-II were calculated and then, a unique numerical index presenting an estimation of overall workload was extracted. In the next step, three tests with different levels of workload were conducted to examine the validity of the offered criteria. These tests were performed by a group of subjects on the role of human pilots, while recording their own experiences about perceived workload via NASA-TLX.

Results: The results confirmed that there were significant differences between averages of scores assigned by subjects to the total workload, for three levels of difficulty defined based on information theory (P-value < 0.001). This variable shows considerable growth from low to medium and from medium to high categories of workload level.

Conclusions: The proposed quantitative index is effective enough for determination of workload levels in the MATB-II simulator.

Introduction: Heavy load lifting or occupational and individual factors are effective hazard agents in the occurrence of musculoskeletal disorders. Therefore, the aim of the present study was investigating the correlation of musculoskeletal disorders with work ability index and allowable load lifting limit.

Methods: This analytical and cross-sectional study was conducted using census (n = 60) among the kitchen workers in Qazvin teaching hospitals in 2016. Data were collected through questionnaires including pain prevalence, work ability index and allowable load lifting limit. Data was analyzed by single and multiple regression logistic using SPSS 16 software.

Results: The highest prevalence was observed in the lower back (78.3%). Of the workers, 61.7% reported a good level of work ability index and 58.3% of the workplaces were in unsafe conditions of load handling. Unsafe condition alone increased the prevalence of shoulder and neck pain about 7 times and the lower back pain 4 times, and in interaction with other risk factors, the prevalence of neck and shoulder pains had 25 and 28 times increase, respectively. Also, subjects with good levels of ability compared to subjects with excellent levels of ability were 9 times more in exposure of musculoskeletal disorders.

Conclusions: Risk factors such as body mass index, work ability and allowable load lifting limit can affect the prevalence of musculoskeletal disorders. So, selection of subjects with good and excellent work ability levels and compliance with the load limit are the effective solutions in increasing the productivity and reducing musculoskeletal disorders among kitchen workers.

Introduction: Few studies were conducted to determine the effects of lighting on cognitive performance. However, they could not reach a decisive conclusion. This study investigated cognitive performance of university students exposed to different levels of lighting under laboratory conditions.

Methods: In this experimental study, 33 subjects (age range 19-26 years) performed cognitive tests. Participants were exposed to three levels of lighting (200, 500 and 1500lux) in laboratory conditions while performing CPT tests to investigate percentage of attention and reaction time machine that measures reaction time.

Results: The results of this study showed that the maximum percentage of attention (99.75%) belonged to lighting of 1500 (lux) and the minimum percentage of attention was related to 500(lux) (99.36%). statistical analysis showed significant differences in percentage of attention in different levels of lighting (P=0.004). In addition, results of data analysis showed that increase in intensity of  lighting can make a significant change in the average response time (P˂0.001), correct response (P=0.004), commission error (P=0.001) and omission error (P=0.017). With increasing the lighting intensity, reaction time has decreased. The reaction time showed significant differences  at all levels of lighting (P˂0.001)

Conclusion: According to the findings of this study, lighting causes a decrease in reaction time and increase in attention. Thus, the lighting should be taken into account while designing of job and tasks which need attention or reaction time.

Abstract:

Introduction: Work-related musculoskeletal disorders (WMSDs) occur when the pressure that applied to musculoskeletal tissue is/be more than tissue tolerant capabilities. This study aimed to assess the risk factors cause musculoskeletal disorders associated with manual tasks using ManTRA and conducted ergonomics intervention program(educational- engineering) among workers in the printing industry.

MethodS: In this interventional case-control study, 40 workers who performed manual tasks, ( 20 case group and 20 control group) were chosen and were investigated. Nordic Body Map was used to determine the intensity and position of pain in the Different part of the body.  ManTRA method was performed to evaluate cumulative scores in four regions of the body (wrist / hand / arm - shoulder / neck - back - lower limb) for each workers before and after the intervention. Data analysis was done using SPSS.

Results: Data analysis showed that mean intensity of  pain in the control group before and after intervention in the various regions of the body such as  head /neck (p=0.012), right shoulder/arm (p=0.012), left shoulder/arm(p=0.043), back (p=0.003), right hand / wrist (p=0.028), left hand / wrist (p=0.027), right knee/ hip (p=0.005), left knee/ hip (p=0.005), right leg (p=0.012) & left leg(p=0.028) were significant.Cumulative score was also significant in the body regions such as arm/wrist /hand (p=0.001) and shoulder /neck (p=0.001) before and after the interventional program.

Conclusion: On the basis of the findings of this study, it could be noted that the ergonomic interventional program was effective to reduce the intensity of pain in the various regions of the body and risk factors causing cumulative damage in the workplace.

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Introduction: In some occupations such as nursing, due to specific job circumstances, sleep quality is poor. Given the importance of sleep quality, this study examined the impact of sleep health education on sleep quality among nurses.

Methods: This was an interventional and quasi-experimental research. The study population included the nursing personnel serving at elected Lorestan university hospitals. Among them, 50 were randomly assigned to a control group and 50 were selected as the intervention group. Data collection was organized according to a questionnaire posing demographical questions as well as Pittsburgh Sleep Quality questionnaire. Training intervention for the intervention group was carried out. Consequently passing 45 days, both control and intervention groups were called out for questionnaire filling. Data analysis was conducted using SPSS software, independent t-test and McNemar’s test.

Results: The study results showed that after the intervention training, there was a significant difference in terms of the average sleep score among the personnel of nursing, and after the training intervention, the sleep status of the personnel got improved compared to those of the control group (P ≤ 0.05).

Conclusions: The study results showed that sleep quality-improving skills trainings had an important and decisive impact on the sleep quality of nursing personnel and holding educational courses in this field for personnel can be useful.

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: A significant number of employees of any organization experience burnout, in many different countries. It is obvious that burnout prevention and mental health promotion play an important role in the improvement of the quality of services. One of the strategies that could be useful in reducing premature aging is deployment of a total ergonomics (ergonomics micro and macro). The main objective of this study was to investigate the relationship between variables considered in the context of total ergonomics and burnout.

Methods: The sample was selected from one of the hospitals in Yazd, including various departments with 506 employees. The sample size of 216 was determined according to Morgan. The data were collected through questionnaires and samples were selected through a stratified random sampling method.

Results: The results showed that moderate job burnout and perceived organizational support by the employees was lower than average, and there was a significant negative relationship between burnout and variables involved in comprehensive ergonomics. The study showed that demographic variables of burnout were effective on employees.

Conclusions: This study investigated burnout level, organizational support, organizational justice and physical environment. The reduction of Burnout was assessed by improved total ergonomic (macro and micro ergonomic) conditions. The results obtained in this study correspond with the results of various research studies. At the end of the study, based on the results, suggestions were made to reduce burnout.

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: One of the most important issues in industries is accident. Various factors affect these events, one of which is individual features. This study aimed at investigating the role of human resource personality on human reliability in accident outbreaks using DISC behavioral approach modal in automotive industry.

Methods: This was a descriptive-analytical research. The relationship of person vulnerability with human personality with fallibility was investigated. In order to determine human personality disk standard model was used and to estimate the degree of human fallibility heart techniques were used. Then, the relationships of natural personality, human reconcilable dimensions, human reliability and fallibility were found. Also, the relationship of accident repetition with personality and human fallibility was determined. This research was conducted among 98 personnel of one of the biggest production units during 2013 to 2015.

Results: The results indicated that there was a high correlation in human personality and fallibility dimension with accidents outbreak. There was a significant relationship between persons with influential personality, inherent stability, adapted stability, adapted dutiful, and accident outbreak repetition.

Conclusions:  According to the results, the personality of individuals with high sensitivity in their job and less adaptation to changes made in work environment, has a higher possibility of accidents outbreaks. Perhaps, this issue is created because of the inconsistency between the management system that is ruling the industry of developing countries and personality features of those people.

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.

Introduction: Metro driving is one of the newest jobs in Iran. Due to the lack of studies about train drivers’ workload, there is no comprehensive information about factors that effect workload. This study aimed at analyzing the factors that may effect driver workload, in order to recommend control measures.

Methods: In this mixed method study, data generation was done through field observations, document reviews, individual interviews, focus group interviews, and focus group discussions. In order to perform field data collection, the institute for occupational ergonomics and CCD Design and Ergonomics Ltd’s developed tools were used. Directed content analysis was used for qualitative data analysis.

Results: Overall, 65 factors were extracted as the factors that may effect driver workload. The extracted factors were drawn on a fishbone diagram, over 8 categories, including management, supervision and organizational climate, infrastructure, job design, journey, and environmental as distal factors and time pressure, information exchanges, and individual factors as proximal factors.

Conclusions: Some of the distal factors are the nature of an urban transport system, so the only amendment is compensatory programs, and some of them could be resolved by long-term plans. Workload of train drivers could be reduced with a focus on the proximal factors in the short-term, and the distal factors in the long-term.