Iranian Journal of Ergonomics

Introduction: The quality of work life is one of the main issues in human resource management that is related to job satisfaction, resignation, turnover rate, personality and job stress. The present study was conducted to investigate the quality of working life in relation to stress levels and participation in health care workers in cities.

Materials and Methods: The present cross-sectional study was conducted on 124 random health care workers employed in centers across the city of Hamadan. Walton's quality of work life questionnaire, Belcher's participation questionnaire and a stress questionnaire were used for achieving the study objectives. The Pearson test was used for determining the correlation between the variables.

Results: The results showed that 40.3% of the subjects reported their overall participation rate to be low, 38.7%% reported it to be moderate and 21% reported it to be high. In addition, 73.4% of the subjects reported low levels of perceived stress and 26.6% reported it to be very high. The findings of the study showed a significant positive correlation between participation and the quality of work life (r=0.33 and p<​0.001). The quality of work life and stress were also found to have a negative correlation (p=0.015 and r=-0.219).

Conclusion: Through understanding participation and levels of stress among the employees and through presenting and implementing appropriate strategies for reducing stress and encouraging participation, the quality of work life and ultimately the productivity of health care organizations can be increased.

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.

Background: The aim of this study was to investigate the effect of the heel wedges on the electromyography activities of the selected left and right lower back muscles during load lifting.
Methods: A total of 17 male subjects voluntarily participated in this quasi-experimental study. The selected subjects lifted a box, weighing 10% of their body weight, above the height of their hip joint, descending as far as the thigh, parallel to the ground, and then ascending to the starting position. The above task was performed nine times in two conditions, including with and without the heel wedges. Using the ME6000 electromyography system, the activity level variables were normalized and the median frequencies of the erector spinae (ES) and the multifidus (MU) muscles were recorded. The subjects also held the box for 30 s in the standing position with stretched hands. The paired t-test was used for the data analysis.
Results: The results showed that during static load lifting using the heel wedge, the median frequency of the right ES muscle changed significantly (P<0.05). Also during dynamic load lifting using the heel wedge, the activities of the left and the right ES muscles as well as the left MU muscle decreased significantly (P<0.05). However, no significant differences between the two conditions were observed for the other variables (P>0.05).
Conclusion: During such occupational tasks, a decrease in the activities of the selected lower back muscles with the heel wedge might result in a delay in the onset of muscle fatigue. The above findings might be used in the design of shoes, suitable for the work environments. However, further investigations are needed in this area in order to provide more accurate results.