1.    Introduction
Low back pain is a common problem worldwide, with most people experiencing it at least once in their lifetime. The 1-year incidence of first-time back pain is estimated to be between 6.3% and 15.4%, while the 1-year incidence of any episode of back pain ranges from 1.5% to 36% (1). In most individuals who experience activity-limiting back pain, the problem tends to recur. The initial onset of back pain typically occurs in the third decade of life, and its prevalence increases until around age 65, after which the incidence decreases (2). When the pain persists for more than 3 months, it is classified as chronic or continuous back pain (3), which can lead to disability, obesity, impaired strength, flexibility, endurance, and performance (4). Specifically, in terms of movement, the preferred walking speed in individuals with back pain decreases from 1.31 m/s in healthy individuals to 0.92 m/s in those with pain (5). This altered behavior is associated with a reduction in the range of motion of the scapula and pelvic girdle during walking (6). Alleviating back pain is crucial for improving performance. Therefore, given the challenges in treating back pain, the lack of consensus, and the limited evidence regarding the nature and role of changes in this condition, the need for research on the effectiveness of an eight-week TRX exercise program in patients with nonspecific chronic back pain is emphasized.
2.    Methods
This research is a semi-experimental study conducted on 30 women aged 35 to 55 years with nonspecific chronic back pain, who were active in 6 sports clubs in Isfahan city. The subjects were selected based on availability and then assigned to two training groups. One of the inclusion criteria was the absence of any medical prohibition against exercise. Additionally, if a subject was unable to perform the exercises due to a problem, she was excluded from the study. At the beginning of the study, written consent was obtained from each participant to voluntarily take part in the research. Subsequently, the subjects' height, weight, and pain levels were assessed using a questionnaire. The degree of kyphosis and lordosis was measured with a flexible ruler, and their motor performance was evaluated using the Functional Movement Screening (FMS) test. After the initial evaluations, the training groups participated in a selected exercise program for 8 weeks, with 3 sessions per week. Post-test measurements were taken and recorded after the completion of the 8-week exercise regimen. For the experiment and inferential analysis of the data, as well as to determine possible differences between group means at various stages of the research, analysis of covariance and paired t-tests were used if the data distribution was normal. In cases of abnormal data distribution, the U-Mann-Whitney and Wilcoxon tests were applied to assess differences. Data analysis was performed using SPSS software, version 24, with a significance level set at P ≤ 0.05.
3.    Results
Considering the normality of the data related to movement function, kyphosis, and lordosis, as determined by the Shapiro-Wilk test, and the establishment of homogeneity of variance, which was investigated using Levene's test, analysis of covariance (ANCOVA) and paired t-tests were used to investigate the effect of training and compare the groups. The results of these analyses are presented in Table 1.

The results of this study showed that both the weight training program (P ≤ 0.01) and TRX (P ≤ 0.01) had a significant effect on pain relief, motor function screening test scores, kyphosis, and lordosis. In comparing the two training groups, no significant difference was observed between them, except for the kyphosis variable (P = 0.002), where a difference was detected (P > 0.05).
4.    Conclusion
Overall, the results of this research demonstrated that both weight training and TRX programs effectively reduced pain, decreased the kyphosis and lordosis angles, and improved motor performance screening test scores. Since both types of exercises target the trunk area, they not only reduce pain and musculoskeletal disorders but also appear to lower the risk of injury and enhance performance by improving movement efficiency. Additionally, by incorporating exercises that strengthen the core muscles and promote limb movement, it can be concluded that participation in these programs improves the functional performance of women with musculoskeletal pain.
Ethical Considerations
Compliance with ethical guidelines
There were no ethical considerations to be considered in this research.
Funding
This research did not receive any financial support from government, private, or non-profit organizations.
Authors' contributions
All authors equally contributed to preparing article.
Conflicts of interest
The authors declare that there are no conflicts of interest associated with this article.