Among the work departments muscles of

Among the 2 work departments, muscles of workers at the metal stamping process lines were observed to experience fatigue later than those at handwork section during beginning of the workday as shown in Fig. 8. In other words, exposure to 1 hour and 15 minutes of WBV induced muscles of workers at the metal stamping process lines to be vigorous. However, the muscles of workers at the metal stamping process lines appeared to experience fatigue rapidly for middle of the workday, and end of the workday as illustrated in Figs. 9, 10 respectively Based on this situation, long term and continuous exposure to WBV (2 hours and 2.5 hours during middle of the workday and end of the workday respectively) have contributed to fatigue in the muscles.
Furthermore, low frequency of vibration generated by the stamping machine can be another contributor to fatigue. Many studies in occupational health, safety and ergonomics believed that continuous exposure to WBV initiated muscle fatigue and increase the risk of lower back pain [31-34,39,40]. In a radiological study, it purchase BGJ398 was proven that continuous exposure to WBV causes morphological changes in the lumbar spine thus lead to back pain [41]. In addition, over exposure to WBV in daily job activities can lead to various health implications such as damage of central nervous system, insomnia, headache and shakiness, and decreased job proficiency [42].
This study proposes several solutions as control measures to minimize muscle fatigue associated with prolonged standing. Standing with intermittent sitting is the best solution to minimize discomfort and muscle fatigue associated with prolonged standing tasks. Sitting is a much less strenuous posture than standing, mostly because it requires fewer muscles to be contracted to stabilize the body. In addition, when the processes jobs are performed in sitting position, the loading on the upper limbs will be uniformly distributed through the seat pan [43], hence reduces the loading on the lower limbs. However, sitting in long periods of time is also not good for the health. Alternate the standing and sitting positions using sit-stand stool enable the workers to perform the jobs in sitting as well as standing position. Moreover, the sit-stand stool is equipped with a foot rest to provide comfort to the workers’ legs. Also, it can be rotated 360 degrees so that the workers can reach the materials without twisting their body and consequently enlarge the degree of freedom to do the jobs. Besides, comfort shoe design, adequate work rest, and applying anti-fatigue mat could be alternative solutions to minimize the risk of discomfort and muscle fatigue associated with prolonged standing.
By using the approach of engineering controls, application of anti-fatigue mat on the standing surface of workstation can absorb pressure in the workers’ feet due to hard standing floor [44,45]. Alternatively, providing a soft shoe-insole can reduce fatigue in the feet due to body mass and workload while performing processes jobs in prolonged standing [46]. In cases where engineering controls are impossible to be implemented, administrative controls such as providing micro breaks in the working hours can be applied to minimize muscle fatigue due to prolonged standing. It has been proven that providing breaks in the working hours can minimize risk of leg swelling due to prolonged standing [7].

Conflict of Interest

Acknowledgments

Introduction
Work-related psychosocial risks concern aspects of work design, management, and the social and organizational contexts that can cause psychological or physical harm. Work-related stress is among the most commonly reported causes of work-related illness, affecting more than 40 million individuals across the Eropean Union (EU) [1].
In recent years various international organizations have set initiatives in motion to raise awareness regarding the psychosocial risks of work-related stress. In 1999, the European Parliament urged the European Commission to analyze additional problems that were not covered by existing legislation, such as stress, fatigue, and aggression [2]. The World Health Organization, in its Ministerial Conference on Mental Health in 2005, emphasized the importance of mental health, well-being and prevention, treatment, care and rehabilitation for mental health problems; these issues were referred to the context of the workplace, and acknowledged the important role of research. In addition, European social partners have started to take action, by first publishing important relevant documents. The objectives of substitution paper are: 1) to review the main European documents and directives concerning work-related stress; and 2) to examine four models, developed by European countries, for the assessment and management of work-related stress.