Background and Aim: The lack of balance between job needs and workers' physical capacity may lead to work-related musculoskeletal disorders (Wises). WMSDs are one of the most important occupational health problems in developing countries. These problems are due to risk factors such as poor work postures, excessive force applied, repetitive movements, vibration, prolonged work duration, and psychological factors, leading, ultimately, to disorders ranging from mild low back pain to severe disabilities. This study aimed at determining the prevalence of WMSDs in different body regions, assessing posturing, and detecting ergonomic and individual risk factors causing musculoskeletal disorders, in Araki bakery workers in Arak, Iran.

Methods and Materials: In this cross - sectional study 233 randomly selected bakery workers in Arak were included, and the prevalence of symptoms of musculoskeletal disorders and their risk factors, with particular emphasis on work posture, was determined in them. The method used was OWAS and the NMQ Questionnaire.

Results: The highest prevalences of musculoskeletal disorders were in the knees (62.2%), low back (58.8%), legs (53.9%) and shoulders (44.6%) of the workers. Low back and shoulder injuries in Shaaters (workers in charge of baking the bread) and elbow, thigh and low back disorders in Choongeers (workers in charge of dividing and rounding the dough) were more prevalent than in other occupations. There is a positive association between type of occupation and these disorders (p<0/05). According to the OWAS's classification, the distribution of bakery workers' working postures was as follows: 58.5% in the action category 1 (natural posture), 34.7% in the action category 2 (stress posture), 4% in the action category 3 (harmful posture), and 2.5% in the action category 4 (very harmful posture). There was a significant relation between work service record and neck, elbow, shoulder, and knee disorders (p<0/05).

Conclusion: This study revealed that the working postures of 42.2% of Aaraki bakery workers were slightly to very harmful postures; in addition, there was a high prevalence of WMSDS in different body regions of the workers. Ergonomic interventions are essential to improve the situation and protect better the health of the workers.