as job insecurity, skill discretion, job strain and social support play an important role in maintaining work ability. A positive combination of "psychosocial characteristics" of the job with "individual resources" can promote work ability in such occupations. Work ability is a multifaceted and multidetermined concept not only associated with health but also with competence, values, the working environment and social relations 1) . The level of work ability in the working population can predict both future permanent disability and duration of sick leave absences 2,3) . So far, a large variety of studies have addressed determinants of work ability in occupational populations with predominantly physical demands at work. From these studies, it is known that WAI in such occupations is influenced by various factors like health problems, lifestyles, individual characteristics and many work-related risk factors [4][5][6] . Among the work-related risk factors, Alavinia 7) showed a strong association between psychosocial and physical factors and impairment of work ability.However, a few researches identified a number of psychosocial factors in the work environment as risk factors for work ability. Tuomi 8,9) showed that dissatisfaction with supervisor's attitude, lack of freedom, decrease in recognition and esteem and role ambiguities at work were associated with impaired work ability among municipal workers. Similarly, lack of support at work, poor possibilities to control one's own work and poor management were also associated with a lower WAI among construction workers and home care workers 7,10) . Although the relationship between work ability and some psychosocial factors has been described in In recent decades, work ability index (WAI) has been a common practical tool to measure individuals' work ability in many European, Asian and South American countries. However, there is no study concerning work ability in Iran. The aim of this study was to determine the work ability index in an Iranian petrochemical job setting and to examine its relationship with psychosocial factors. Methods: A cross-sectional study was conducted among 420 male workers in various occupations. Work ability was evaluated using the WAI questionnaire developed by FIOH; the Job content questionnaire (JCQ) was used to assess psychosocial factors. Results: The mean WAI score was 39.1 (SD=5.7) among workers in the studied petrochemical industry. Multiple linear regression analysis revealed a significant association between mean WAI score and age, job tenure, educational level, rest and sleep status and vocational education. Moreover, the results showed that skill discretion, coworker support and supervisor support were positively associated with the mean WAI score. On the other hand, it was inversely associated with job demands, job strain and job insecurity. Conclusions: This study was the first research to determine WAI in an important industry in Iran. Overall, work ability was in the "Good" category among the workers in the studied field. On the...

Objectives: Prolonged sitting with a flexed back and neck is recognized as being associated with an increased risk of neck and back pain disorders among overhead crane operators. The aim of this study was to compare back and head postures over a full shift of work between operators who experience back and neck pain, and healthy operators. Methods: In a first phase, the prevalence of musculoskeletal symptoms was assessed using the Nordic questionnaire among 120 crane operators. Based on first phase results, 17 operators with back/neck disorders were matched with 15 healthy operators based on age and selected to participate in the second phase of the study. Postures and movements were continuously measured over an 8 h shift using inclinometers.Results: The highest 12-month prevalence of musculoskeletal disorders was found in the lower back, neck and knees. Case and control groups differed significantly in back and head flexion angles at the 50th percentiles APDF (p < 0.05). There was also a significant difference in the time spent working in an extreme posture of the back and head between groups (p < 0.05). Conclusions: This is the first study to document work postures assumed during a full work shift and to compare postures between symptomatic and healthy overhead crane operators. Physical exposure in case group operators was characterized by more awkward and extreme postures in the back and head. The results of this study demonstrate that effective prevention strategies directed towards musculoskeletal disorders are required that address awkward work postures for overhead crane operators.

Overall, train drivers in long-haul trips had longer rest hours between the ways going and coming back, which seems to compensate for the side effects of longer driving durations.

No abstract

Awkward neck postures are commonly documented to be associated with an increased risk of neck disorders. This study intended to continuously monitor and evaluate neck postures and to estimate the cervicothoracic loads among overhead crane operators during work time. Neck postures were measured among 40 randomly selected operators by an inclinometer during 2 h of work time. To determine the tasks and adapt the posture recordings to each of their corresponding tasks, direct observation was conducted concurrently. The median neck flexion and lateral bend angles were 28.23° and 11.30°, respectively. The mean compression and shear loads on the neck ranged from 75.22 to 113.14 N and from 9.50 to 41.11 N, respectively. The results indicated substantial levels of exposure to awkward and extreme neck postures among the operators. The nature of the operators' work and the visual requirements of some tasks will increase the mechanical loads on the neck.