Musculoskeletal Disorders in Workers-risk factors: What Can We Do?

Musculoskeletal lesions are very common in workers. Studies show a wide variety of risk factors, from physical, physiological, ergonomic or psychosocial. It is known that higher the risk most affected is the health of workers. The major challenge of the last few decades has been to minimize such risk factors as well as find strategies to compensate certain efforts that are inevitable to work. The aim of this study was to check which strategies best suited to the workplace and improve the quality of life for workers. Publications were searched from 1980 to August 2011 in several databases. Comparative controlled studies, such as randomized controlled trials, controlled clinical trials, cohort studies, of therapeutic exercises compared to control or active interventions in workers. The study confirmed that the prevalence of musculoskeletal pain is in low back. The frequency is related with whole body vibration, as well as with prolonged sitting position, poor body posture and physical work load (lifting and carrying loads). The results of the study suggest that the repeated or constant exposure to mechanical shocks may increase the risk of low back pain. Sedentary activity was associated with higher prevalence rates of low back symptoms. Interventions involving workers, health professionals and employers working together were more consistently effective than other interventions. It was found the strategies that seem to be most effective is to increase physical activity through the exercise and change of habits. To be effective it is necessary to involve all economic agents and health professionals.

Since the early eighteenth century, the musculoskeletal disorders were recognized as being based etiological factors and occupational. However, only since the 1970s is that occupational factors were studied using epidemiological methods, and studies that linked the work with these factors began to appear regularly in international scientific literature. Since then, the evidence resulting from the development of more than six thousand scientific articles published only address the importance of ergonomics in the workplace [1]. However, the relationship between the musculoskeletal disorders work-related and other factors, it remains a matter of debate [1]. The same kind of controversy has been the subject of study under other conditions, including cancer and lung problems, both with multifactorial causes [1].
With the increasingly competitive market nowadays productivity is the watchword, and companies seek different strategies to survive this new reality [2]. Some follow the strategy of improving quality, modifying its productivity and its organizational structure. However, the difficulties encountered in the implementation of better quality, are mainly due to the scarcity of skilled human resources in which machines are indispensable and man is considered just another element of the production system, often inadequate to their individual characteristics. In most jobs each subject carries out its activities for a specific limited period of time, almost always reduced, inducing workers to perform their duties on time, even when it endangers their health [2]. This type of conviction often leads to disability and functional limitations in activities of daily living, as well as professional, restricting the participation of the individual in society [3,4].
The World Health Organization (WHO) characterized the injury as work-related multifactorial diseases due to various risk factors involved, such as work organization, physical, psychosocial and socio cultural as well as ergonomic, contributing to the cause of these problems [5]. One of the main controversies surrounding the musculoskeletal symptoms related to work is its multifactorial nature. Some study centers are not in agreement on the relationship between multiple risk factors and individual development of this disease [5]. However, musculoskeletal disorders are becoming increasingly frequent thus becoming a major problem in industrialized countries [6][7][8][9]. Represent a major cause of morbidity and have been described as being the most common symptoms of severe prolonged pain and disability in the labor force [6,7,[9][10][11][12].
The European Foundation for the Improvement of Living and Working Conditions [13], points out that Portugal is the third country in the EU where more workers are missing due to musculoskeletal disorders.
In 2001, the National Institute for Occupational Safety and Health based on various publications built a conceptual model for musculoskeletal injuries. In this model, it determined possible effects resulting from the application of loads. This may be due to external or internal forces resulting from gravitational effects and dynamic loads applied. These create internal responses of muscle, ligament and joint surfaces. As the size of the load and individual factors, organizational or social, the results can trigger adaptation effects (increases in strength, endurance and physical fitness or be harmful (such as pain or even

Abstract
Musculoskeletal lesions are very common in workers. Studies show a wide variety of risk factors, from physical, physiological, ergonomic or psychosocial. It is known that higher the risk most affected is the health of workers. The major challenge of the last few decades has been to minimize such risk factors as well as find strategies to compensate certain efforts that are inevitable to work.
The aim of this study was to check which strategies best suited to the workplace and improve the quality of life for workers.
Publications were searched from 1980 to August 2011 in several databases. Comparative controlled studies, such as randomized controlled trials, controlled clinical trials, cohort studies, of therapeutic exercises compared to control or active interventions in workers.
The study confirmed that the prevalence of musculoskeletal pain is in low back. The frequency is related with whole body vibration, as well as with prolonged sitting position, poor body posture and physical work load (lifting and carrying loads). The results of the study suggest that the repeated or constant exposure to mechanical shocks may increase the risk of low back pain. Sedentary activity was associated with higher prevalence rates of low back symptoms. Interventions involving workers, health professionals and employers working together were more consistently effective than other interventions.
It was found the strategies that seem to be most effective is to increase physical activity through the exercise and change of habits. To be effective it is necessary to involve all economic agents and health professionals. Workers are often subjected to repetitive movements and vibration, the lifting and transport of weights, incorrect postures for prolonged periods of time is sometimes long working hours [18-28]. These factors put the soft tissue tension, rising progressively to musculoskeletal disorders [25,29,30].
The musculoskeletal symptoms may still arise or be exacerbated if the work involves exposure to low temperatures. Some authors [31] found a high prevalence of musculoskeletal symptoms workers in areas of very cold (2°C), especially in the lower back, neck and shoulders. Other authors state that the cold reduced muscle performance, leading progressively to a voltage increase fatigue and subsequent premature [21]. Moreover, the psychosocial burden that the worker is subject, plus a weak social support and low job satisfaction develop a mechanism that stress leads to increased muscle tone and activation of pain receivers, enhancing musculoskeletal pain [29,32-34].
According to the European Foundation for the Improvement of Working Conditions Living and [13], musculoskeletal disorders more common among workers in the U.S. are low back pain (25%) and generalized muscle pain (23%). The musculoskeletal disorders can be measured by symptoms reported by workers, being considered as the presence of symptoms of pain, suffering or discomfort. Affect all anatomical regions of the spine and upper limb or lower [26,35-37]. However, low back pain is a condition that involves greater morbidity and disability, affecting considerable financial costs comprising 58-84% of active adults [38-45].
Low back pain can restrict the function with personal consequences, interpersonal and social, such as loss of independence, and inability to perform various activities in social life and can even interfere with basic activities such as standing, walking and dressing, reducing the quality of life as well as the many activities related to job performance [46][47][48][49].
In addition to physical factors, several studies have shown that psychosocial factors inherent in the job, as authority for decision, psychological job demands, support from supervisors, dissatisfaction and job insecurity contribute to the declining state of health workers The exercise programs have proven to be most effective in the prevention and treatment of back pain than conventional therapies, resulting in reduced pain and more functionality, reducing absenteeism low back pain [50]. In a recent review, the authors found strong evidence among exercise programs and prevention of back problems [60]. Another study found that there is support for it can be said that the exercise programs improve flexibility and muscle strength at the rachis [61]. However, there is still some controversy regarding the effects of exercise, found no positive effects on their intervention in industrial workers. On the other hand, a more recent study [62] found that exercise programs were effective in reducing pain and functionality but only in the short term [63]. These results may be due to communication problems or dissatisfaction and high expectations created [64,65].
A well structured exercise program should decrease symptoms, pain and increased strength that enables individuals to fulfill their tasks with less effort [6,[66][67][68][69]. These same exercise program specific to the lumbar region have been effective in reducing pain, reducing the required performance required for daily activities, as well as the inability [68], thus inducing a significant improvement of quality of life in individuals [70,71].
Although European guidelines do not recommend the type and intensity of exercise, they recommend programs should be carried out taking into account the repeated movements and tasks that individuals perform during their work [6,72]. Workers should be instructed on how to perform the exercises and should reinforce the idea that the physical, social and mental are the foundations of quality of life [6,72].