1. Introduction
ynamic Knee Valgus (DKV) is a common risk factor for acute lower extremity injuries and overuse. Generally, excessive movement of the knee in the frontal plane during sports activities is a known cause for many acute and chronic knee injuries [1]. Researchers have identified DKV as a risk factor for lower limb injuries, including Patellofemoral Pain Syndrome (PFPS) and ACL rupture So that the reduction of knee valgus by maintaining proper alignment during activity has been reported to be an influential factor in preventing non-collision ACL injuries and PFPS [2]. 
DKV is a combination of adduction and internal rotation of the thigh with the abduction and external or internal rotation of the tibia during landing or squat maneuvers. The knee valgus is caused by a combination of femoral and tibia movements affected by the knee’s proximal and distal joints, including the trunk, thighs, and ankles [3]. Since reducing valgus loads can effectively reduce the incidence of ACL injuries, so far, many researchers have investigated the effect of ACL injury prevention exercises on neuromuscular function and variables [6]. However, despite the importance of using preventive exercise programs in people with DKV, which is one of the most critical risk factors for ACL injury, few studies have addressed this issue. On the other hand, the existing training approaches to improve knee joint function are very diverse, and research on identifying the best training methods to improve motor function is ongoing. Many kinds of research suggest quadriceps muscle strengthening exercises as a useful method [5, 6, 7, 8, 9]. 
In some studies, strengthening the external rotator cuff muscles and thigh abductors has improved patients’ patellofemoral angle with patellofemoral pain [10]. Earl and Hatch (2011) consider supporting the hip joint muscles as an effective way to improve people’s motor function with patellofemoral pain. By doing these exercises and the thigh’s external rotation, the patellar movement path is better positioned between the thigh’s two condyles. As a result, it improves pain and subsequent function [11]. 
Nowadays, exercises with obstruction of blood flow are used as a side strategy after surgery or before gaining health and complete recovery from injuries in muscle weakness cases around the injured joints, intending a rapid recovery [17]. Since no research has compared the effect of strengthening exercises on quadriceps, abductors, and external rotator cuff muscles compared to these exercises along with blood flow obstruction in people prone to knee injuries, including people with DKV; therefore, in this study, we will compare the effect of conventional resistance training with and without restricting blood flow on the motor function of women with DKV.
2. Materials and Methods
This research was a quasi-experimental and interventional study with three groups and pre-test and post-test. The present study’s statistical population consisted of active women with DKV deformity in Chalous city at 18-28. To determine the number of samples required for this study based on similar reviews [16] was used. Thirty-six people were purposefully selected from women with DKV as research samples. Subjects were evaluated for the patellofemoral joint’s direction with a goniometer, static and dynamic balance through Stork and Yaw Tests, and lower limb strength with Sargent Jump Test. Subjects were randomly divided into control, conventional resistance training without restricting blood flow, and traditional resistance training restricting blood flow. Exercises were given for 8 weeks in three sessions per week. The Guilan University of Medical Sciences approved this research (Code: ID IR.GUMS.REC.2020.202).
3. Results 
The results showed a positive effect of exercise programs on static balance (P=0.001), dynamic balance (P=0.001), patellar alignment, and lower limb strength (P=0.001) in women with DKV. Also, the results of the analysis of covariance showed a significant difference between control and training groups (Table 1). 


4. Discussion and Conclusion
The results of the present study showed the positive effect of exercise programs on the results of pre and post-tests of static balance, dynamic balance, the direction of the patellofemoral joint, and lower limb strength in women with VDK defect. Also, comparing the results between the groups showed a significant difference between the control group and the two training groups and was determined by examining Post Hoc Test differences. Comparing the two experimental groups showed a significant difference in the lower limb strength variable between the two training groups.
In confirmation of the results of this study on the improvement of static and dynamic balance variables in both experimental groups, we can refer to Farahani and Riahi’s (2019) study, which examined the effect of exercises restricting blood flow soldiers’ balance. Their result showed that exercise program restricting blood flow significantly impacts improving balance [25]. The positive effect of using exercises with blood flow obstruction on improving balance can be due to lower extremity strengthening exercises, which is an effective factor in balance. In this regard, the results of research by Willardson et al. (2013) examined the effect of exercise by restricting the blood flow in different parts of the body with varying intensities in improving endurance and strength [26].

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethics Committee of the Guilan University of Medical Sciences (Code: IR.GUMS.REC.1399.202). 

Funding
The paper was extracted from the MSc. thesis of Seyedeh Mahshid Hadavi at the Department of Sport Injuries and Corrective Exercise, University of Guilan, Guilan.

Authors' contributions
All authors equally contributed to preparing this article.

Conflicts of interest
The authors declared no conflict of interest.


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