INTRODUCTION
Prolapse is the descent of one or more pelvic organs, such as the bladder, uterus, or rectum, into the walls of the vagina (1). The symptoms include a feeling of heaviness in the vagina, a feeling of a mass descending into the vagina, discomfort due to pelvic pressure, and back pain. These symptoms can cause a variety of problems, including pain, urinary and bowel problems, difficulty defecating, bladder irritation, and sexual dysfunction, which can affect quality of life (2). Treatment for rectal prolapse can be conservative or surgical, depending on the severity of the prolapse and its symptoms, impact on quality of life, general health status, and patient preferences. Conservative treatment includes core and pelvic floor muscle training, lifestyle changes, pessaries, and estrogen therapy, which have a few side effects (5). The goal of core stabilization exercises is to build the physical capacity to improve performance and increase the strength and endurance of the muscles in this area. It is also believed that a weak core causes changes in energy transfer, resulting in decreased performance and risk of injury to weak or underdeveloped muscle groups (10). For this reason, core strength-endurance exercises are popular for improving performance and reducing the risk of injury (10).
On the other hand, core stability exercises also help strengthen the pelvic floor muscles. The pelvic floor plays a critical role in the core and rectal prolapse. Nonetheless, the role of these muscles and the effectiveness of core stability exercises on rectal prolapse in women are not fully understood. In light of the aforementioned issues and considering the paucity of research in this field, the present study aimed to assess the effect of core stability exercises on the endurance and strength of the core muscles in women with rectal prolapse.

METHODS
This quasi-experimental applied research was conducted on women with rectal prolapse aged 40-50 years who were referred to Jay and Mehrparseh medical centers in Isfahan in 2023. Among the patients who met the inclusion criteria, 24 cases were selected using a simple and accessible non-probability method and randomly assigned to two groups of 12 (core stability exercises and control). The inclusion criteria entailed women with rectal prolapse (grades 2, 3, and 4), middle-aged women aged 40-50 years, written consent to participate in the study, ability to perform exercise, general health, and duration of illness of about three years. On the other hand, the exclusion criteria included missing two consecutive exercise sessions, lack of proper cooperation for the intervention, injury to the core area, symptoms of pressure drop during exercise, uterine prolapse, any contraindication to the use of a vaginal probe, and pelvic dislocation. All subjects participated in the study voluntarily. All stages of the research were approved by the Ethics Committee of Islamic Azad University, Khomeini Shahr Branch with the ethics code IR.IAU.KHSH.REC.1402.093. In addition, measurements of height, weight, body mass index (BMI), endurance, and strength of the core muscles were performed in two stages: pre-test and post-test.The core stability exercise program was performed for eight weeks, three sessions per week, from 30 min in the first week to 90 min in the eighth week. The program consisted of nine exercises controlled by observing the principle of additional load and gradually increasing the duration of each exercise concerning correct execution, pressure, and rest between specific exercises, and exercise intensity for each subject based on the exercise tolerance testing. (16). During this period, the control group had their usual activities and treatment methods. The data were analyzed in SPSS software (version 26) using multivariate covariance statistical method and the Bonferroni post hoc test at a significance level of 0.05.

RESULTS
The mean scores of subject's age, height, weight, BMI, and the number of births were 45.2±2.62 (years), 159.4±3.54 (Cm), 68.9±2.33 (Km), 26.2±1.42 (Km/m2), and 3.2±1.1, respectively. In addition, the intergroup and intragroup changes in the endurance and strength of trunk flexors and extensors in women with rectal prolapse demonstrated that after the intervention, the endurance and strength of trunk flexors and extensors in the core stability training group increased significantly (P=0.001). Moreover, the results indicated that there was a significant difference between the two groups with an effect size of 0.68 in the endurance of the flexor and extensor muscles of the trunk in women with rectal prolapse (P=0.002; F=42.19). Furthermore, there was a significant difference between the two groups with an effect size of 0.48 in the strength of the flexor and extensor muscles of the trunk in women with rectal prolapse (P=0.001; F=49.12).

CONCLUSION
The present study aimed to assess the effect of eight weeks of core stability training on core muscle strength and endurance in patients with rectal prolapse. The results of the study pointed to significant increase in core muscle strength and endurance in the experimental group. Although very limited research has been conducted on the effect of core stability training on rectal prolapse, overall, the results of previous studies confirm the effectiveness of core stability training on core muscle strength and endurance and, consequently, the improvement of the disease. As evidenced by the results of these studies, it seems that stabilization training, by improving neuromuscular control and strengthening core muscles, preserves internal organs and prevents prolapse (28, 29). Therefore, it is recommended that sports therapy centers, doctors, and therapists use this training method to improve patients with rectal prolapse. The results of the present study provided a suitable basis for increasing more information and scientific evidence in this field. Given the importance of the issue of preventing rectal prolapse, it is suggested that further investigations be carried out in the form of supplementary studies to achieve more definitive results. This study also had limitations. The present study was conducted solely on women with rectal prolapse. While the duration of this study was eight weeks without follow-up, longer periods with follow-up are likely to be more effective.

Ethical Considerations
Compliance with ethical guidelines
This article was extracted from a master's thesis submitted by Marzieh Zamani with ethics code number IR.IAU.KHSH.REC.1402.093. We would like to express our gratitude to all the subjects, professors, university officials, and those who helped us in carrying out this research.
 

Funding
There was no funding support.

Authors’ Contributions
All authors contributed to the conceptualization and writing of the article, approved the content of the article, and agreed on all aspects of the work.

Conflict of Interest
The authors declared no conflict of interest.

Acknowledgments
None.