Journal of Ergonomics

Introduction: Listening to music during physical activity reduces the perceived stress on body. Hence, this study aimed to evaluate the effects of music genre and sound pressure level on calorie consumption and physical performance of students during treadmill tests.

Methods: In this cross-sectional study, 27 students were randomly selected. A demographic questionnaire, Borg Rating of Perceived Exertion Scale (RPE 6-20), and the Physical Activity Readiness Questionnaire (PAR-Q) were used for data collection. During flat and sloped treadmill running (five minutes at 6 km/hour), two pieces of music with fast and slow tempo (200 and 70 beat per minute) were also played at two sound pressure levels (60 and 80 dB). During the exercise, the students’ heart rate and calorie consumption were measured by a calorimeter (Beurer PM100). At each stage, the physical performance of the participants was estimated using the relevant equation.

Results: The students had the lowest physical performance (61.48) when no music was played and the highest physical performance (92.48) with slow, loud music. The mean heart rate, calorie consumption, and perceived exertion were maximized without music and minimized when slow, loud music was played.

Conclusion: Playing soft music at high sound pressure levels can promote physical performance during exercise by decreasing heart rate, calorie consumption, and perceived exertion.

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.

Background and Objectives: Recognition and prevention of burnout plays an important role in promoting mental health and increasing the quality of services provided. This paper aimed to prevent the occurrence of this problem, seeking to identify the effective factors on the employees' burnout.
Methods: Many studies have been carried out by researchers on staff burnout using a descriptive-analytical approach, but there is no model comprehensively identifying the factors affecting employee burnout and, more importantly, expressing the relationships between the factors involved. Therefore, system dynamics analysis and VENSIM software have been used for explaining the quantitative relationships between factors affecting employees' burnout, evaluation and simulation.
Results: After designing causal, flow diagrams and model validation, four scenarios were extracted using system dynamics and simulation methods. The first scenario, which shows the current status of the company, indicated an increase in burnout. In the second scenario, with increased job satisfaction, employee productivity increased, but higher productivity, in practice, did not lead to reduction in burnout. In the third scenario, burnout decreased with increasing occupational control variables. And in the fourth scenario, by increasing the welfare and rest parameters of the staff, it was found that this scenario also had a significant effect on reducing the burnout of employees.
Conclusion: From among the four simulated scenarios, the fourth one, which is the increase in staff welfare parameters, had the most impact on reducing the burnout of Ardabil Regional Water Company employees.