1.    Introduction
The main cause of long-term decline in performance is work-related musculoskeletal disorders ‎that cause disability (6). Recent US Bureau of Statistics reports that 40 percent of work-related ‎injury compensation is related to musculoskeletal disorders. Which costs about  45  million to  ‎‎54 million dollars annually (7). Other statistics showed that the prevalence of musculoskeletal ‎disorders is much higher in developing or developed countries than in other countries (8). ‎Factors such as repetitive movements, improper posture, delicate tasks with long repetitions ‎and static work are the causes of this type of disorder (9). One of the most common ‎musculoskeletal disorders is low back pain which imposes high costs, both directly and ‎indirectly, on the industrial and non-industrial community (10). Physiotherapy is a widely used ‎method to eliminate low back pain. Also, exercise therapy and corrective exercises are one of ‎the most common methods in this field (11). Research has been conducted to eliminate and ‎reduce musculoskeletal disorders around the world, including in Iran. Corrective exercises, in ‎order to increase strength, endurance, and flexibility have been able to provide an acceptable ‎effect (12). Therefore, these exercises can be considered as a systematic process of identifying ‎defects in neurological, muscular and skeletal function of the body, and designing a scientific ‎program and implementing a coherent corrective strategy. This process includes knowledge, ‎problem identification, program design and problem solving (13). The results of several other ‎studies showed that corrective exercises have led to a significant reduction in musculoskeletal ‎disorders in the lower back, neck, knees, wrists and back (14). Therefore, the aim of the present ‎study was to investigate the effect of eight weeks of corrective exercises and ergonomic ‎recommendations on the frequency of recurrent back pain due to musculoskeletal disorders in ‎the staff of Ardabil Sports and Youth Administration‎.
2.    Methods
This research was applied and quasi-experimental and its data were collected in the field. The ‎statistical population of this study included all employees of the Sports and Youth Department ‎of Ardabil province. The statistical sample of this study was 60 male employees of Ardabil ‎Sports and Youth Administration who were randomly divided into three equal groups of ‎correctional training, ergonomics recommendation, and control with mean age of 41.07±6.47, ‎‎40.73±5.99 and 40.33±5.24 years. They completed the distributed questionnaires. The duration ‎of the training sessions varied according to the type of training and the location of the exercises ‎was considered as the multi-purpose sports hall of Mohaghegh Ardabil University and the ‎ergonomic recommendations of the Ardabil Sports and Youth Administration. According to ‎Table 1, corrective exercises for the intervention group were performed three days a week for ‎‎30 to 45 minutes for eight consecutive weeks. The researcher's recommendations were ‎explained separately to each of the subjects in the ergonomic recommendations intervention ‎group. In addition, each of these employees was given videos in Persian. Teaching ergonomic ‎solutions according to the objectives of the training, including how to sit, the distance between ‎the person and the table, how to use the equipment varied. Shapiro-vilik test was used to ensure ‎the normality of the data, and Wilcoxon test was used to compare the data between groups ‎using SPSS software version 26. Also, a significant level (p≤0.05) was considered for all tests. ‎Excel 2010 software was used to draw the chart‎.

3.    Results
According to the findings of the study, musculoskeletal disorders were prevalent in at least one ‎area of the body of employees. Also, the findings of the present study showed that there is a ‎statistically significant difference between pre-test and post-test frequency of pain recurrence ‎in the group of corrective exercises (P = 0.011). Also, there was no significant difference ‎between pre-test and post-test frequency of pain recurrence in the ergonomic recommendations ‎group (P = 0.063). Furthermore, in the control group, there was no significant difference ‎between pre-test and post-test frequency of pain recurrence (P = 0.112)‎.
4.    Conclusion
Based on the findings of the present study, the rate of musculoskeletal disorders was high in ‎employees and corrective exercises had a significant effect on reducing the frequency of ‎recurrent back pain caused by musculoskeletal disorders. Ergonomic recommendations alone ‎could not be effective. The training protocol used in this study was effective by emphasizing ‎the elimination of incorrect physical posture, improving strength, endurance, and flexibility of ‎employees‎.

Ethical Considerations
Compliance with ethical guidelines
There were no ethical considerations to be considered in this research.
Funding
This research did not receive any grant from funding agencies in the public, commercial, or non-profit sectors.
Authors' contributions
All authors equally contributed to preparing article.
Conflicts of interest
The authors declared no conflict of interest.