Iranian Journal of Ergonomics

Introduction: Physical activity has been identified as a potential intervention to improve body composition in women with breast cancer. This research sought to investigate the effects of an eight-week aerobic training program on some anthropometric indices and cardiorespiratory fitness of middle-aged women with breast cancer.

Material and Methods: A total of 15 women with breast cancer (age: 40-60 years) were selected through convenience sampling. They attended an eight-week aerobic exercise program consisting of three 40-60-minute sessions per week. Exercise intensity was maintained at 30%-60% the subjects’ heart rate reserve (HRR). The participants’ weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist to hip ratio, waist to height ratio (WHR), body fat percentage (BFP), and maximum oxygen consumption were measured at baseline and after eight weeks of exercise. Data were analyzed by paired samples t-tests at a significance level of 0.05.

Results: Significant reductions in the patients’ weight (P = 0.001), BMI (P = 0.001), WC (P = 0.006), HC (P = 0.001), WHR (P = 0.006), and PBF (P = 0.001) were observed after eight weeks of aerobic training. Moreover, exercise significantly increased the subjects’ maximum oxygen consumption (P = 0.008). However, changes in the participants’ waist to hip ratio were not significant (P = 0.235).

Conclusion: According to the obtained results, an eight-week aerobic training program could significantly improve some anthropometric indices and cardiorespiratory fitness in women with breast cancer.

Introduction: Nominal noise reduction rate of the earmuff manufacturers can be different compared with the actual attenuation rate. The present study aimed to determine the actual noise reduction rate of common hearing protection devices using microphone in real ear method.

Materials and Methods: In this study, five brands of common earmuffs used in Iranian industries were investigated on 30 subjects under laboratory conditions. Noise reduction rates of earmuffs were measured based on the ISO 11904 standard, microphone in real ear method, using noise dosimeter (SVANTEK, SV 102 model) equipped with a microphone SV 25 model. The earmuffs comfort was also assessed by the developed questionnaire.

Results: The results showed that the real noise reduction rates of the earmuffs were between 49% to 86% of nominal reduction rates. Moreover, the actual insertion losses were much negligible at low noise frequencies. The performances of earmuffs based on manufacturers were not statistically different (Pv> 0.05). Based on subjects’ comfort scores, comfort of ear muffs were within the acceptable range. The noise reduction rates of the different earmuffs of each model were not statistically different as well (Pv > 0.05).

Conclusions: Irregular use of earmuff can reduce the real attenuation of earmuff to lower than the minimum rate acquired in this study. Proper training and adequate supervision on proper use of earmuff can affect earmuff fitting along with increasing of real noise attenuation.

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.

Background and Objectives: In recent years, due to the rapid growth of metropolitan cities and the shortage of urban public transport means, including urban bus transportation, many people are forced to travel in a standing position when using these vehicles. This situation may cause pain and discomfort and non-collision injuries for passengers. The purpose of this study was ergonomic assessment of the sit-standing seat in passengers standing on urban buses.
Methods: To do this study, 8 young people with a mean age of 25.25±2.12 years were enrolled. For evaluation and assessing the effect of sit-standing seat two methods of surface Electromyography (sEMG) and Borg scale scores were applied in Fall 2018. The data was analyzed using SPSS 24.
Results: In all body parts, except for the hip, the mean scoring of Borg’s scale for perceived discomfort in sit-standing position was less than standing position. Also, the amount of contractile activity of the leg muscles in sit-standing position was significantly lower than the standing position (P<0.05).
Conclusion: Considering the results obtained from the Borg scale scores and the contraction activity of the leg muscles as a result of the use of the mentioned seat, which led to a reduction in the level of discomfort and the leg muscles contraction, it is recommended to apply the sit-stand seat instead of being in a standing position.