Shahid Beheshti University of Medical Sciences The Scientific Journal of Rehabilitation Medicine 2251-8401 9 4 2020 12 21 Electromyographic Activity of the Knee Muscles during Single-Leg Landing in Female Athletes with and without Dynamic Knee Valgus Electromyographic Activity of the Knee Muscles during Single-Leg Landing in Female Athletes with and without Dynamic Knee Valgus 268 277 1101040 10.22037/jrm.2020.113171.2330 FA Farzaneh Ramezani Master of sport injury and corrective exercises, Faculty of physical education and sports sciences, Bu-Ali Sina University, Hamadan, Iran. 0000-0001-9368-4103 Farzaneh Saki Assistant professor of sport injury and corrective exercises, Faculty of physical education and sports sciences, Bu-Ali Sina University, Hamadan, Iran. 0000-0003-3627-1737 Journal Article 2020 02 09 <strong>Background and Aims: </strong>ACL injury is one of the most serious and expensive injuries that is a nightmare for athletes. Increasing the knee valgus angle during dynamic movements such as landing and squat is one of the risk factors for knee injury and decreased mechanical efficiency of movement. The aim of the current study was to compare the preparatory knee muscle activity of female athletes with and without dynamic knee valgus during a single leg landing. <br /><strong>Materials and Methods:</strong> In the current quasi-experimental study, 32 female athletes were divided into two groups of healthy and dynamic knee valgus. Feed forward activities of Medial Hamstring, Lateral Hamstring, Vastus Medialis, Vastus Lateralis, Medial Gastrocnemius, and Lateral Gastrocnemius were recorded during a single-leg landing with the dominant leg on top of a 50-cm box. Muscle feed forward activity was measured since 150 ms prior to ground contact. Multivariate analysis of variance with a significance level of p≤0.05 was used for data analysis. <br /><strong>Results:</strong> The findings of the present study showed that the preparatory Lateral knee muscle activities (Lateral Hamstring, Vastus Laterals, Lateral Gastrocnemius) in participants with dynamic knee valgus was higher than those of healthy individuals (p <0.05). In the case of Medial knee muscles, the results showed no difference between the two groups (p> 0.05). <br /><strong>Conclusion:</strong> According to the results, the preparatory Lateral knee muscle activity was more than that of medial knee muscles in female athletes with dynamic knee valgus compared to healthy female athletes, which increases the risk of knee valgus during dynamic activities, As a result, they are at a higher risk of ACL injury.              <strong>Background and Aims: </strong>ACL injury is one of the most serious and expensive injuries that is a nightmare for athletes. Increasing the knee valgus angle during dynamic movements such as landing and squat is one of the risk factors for knee injury and decreased mechanical efficiency of movement. The aim of the current study was to compare the preparatory knee muscle activity of female athletes with and without dynamic knee valgus during a single leg landing. <br /><strong>Materials and Methods:</strong> In the current quasi-experimental study, 32 female athletes were divided into two groups of healthy and dynamic knee valgus. Feed forward activities of Medial Hamstring, Lateral Hamstring, Vastus Medialis, Vastus Lateralis, Medial Gastrocnemius, and Lateral Gastrocnemius were recorded during a single-leg landing with the dominant leg on top of a 50-cm box. Muscle feed forward activity was measured since 150 ms prior to ground contact. Multivariate analysis of variance with a significance level of p≤0.05 was used for data analysis. <br /><strong>Results:</strong> The findings of the present study showed that the preparatory Lateral knee muscle activities (Lateral Hamstring, Vastus Laterals, Lateral Gastrocnemius) in participants with dynamic knee valgus was higher than those of healthy individuals (p <0.05). In the case of Medial knee muscles, the results showed no difference between the two groups (p> 0.05). <br /><strong>Conclusion:</strong> According to the results, the preparatory Lateral knee muscle activity was more than that of medial knee muscles in female athletes with dynamic knee valgus compared to healthy female athletes, which increases the risk of knee valgus during dynamic activities, As a result, they are at a higher risk of ACL injury.              https://medrehab.sbmu.ac.ir/article_1101040_a8d0743ae9039ef78d46f4206a2a1abb.pdf