Research Paper: The Effect of Selective Plyometric Training on the Lower Extremity Functional Performance Indexes of Female Athletes With Dynamic Knee Valgus

Purpose: Considering the high prevalence of dynamic valgus and its impact on sports performance among the female athletes, the present study aimed to examine the effect of a course of selective plyometric training on the lower extremity functional performance indexes of female athletes with dynamic knee valgus. Methods: This research was a quasi-experimental study with a pretest-post-test design. The study population comprised the athletic girls with dynamic valgus referring to Bu-Ali Sina gymnasium of the University of Hamadan in 2018. Of them, 26 eligible girls who met the inclusion criteria were selected purposefully and then randomly assigned into experimental (Mean±SD age=20.25±2.34 y, Mean±SD BMI=21.27±2.75 kg/m2) and control (Mean±SD age=21.16±2.79 y, Mean±SD BMI=21.60±2.68 kg/m2) groups. The experimental group performed specific plyometric training for 8 weeks, 3 times a week. Assessing the dependent variable was done using dynamic balance, Sargent and Illinois Agility tests in the pretest and post-test. The comparisons between experimental and control groups in the pretest and post-test were made by analysis of covariance and the dependent t-tests, respectively in SPSS V. 20. The significance level was set at 0.05 or lower. Results: Considering the pretest as the covariate parameter, a significant improvement was found for total dynamic balance (P=0.005), anterior leg (P=0.001), medial-posterior leg (P=0.001), lateral-posterior side of right leg (P=0.028), vertical jump (P=0.001) and Illinois jumping test score (P=0.001) in the experimental group. Conclusion: An improvement was seen in the dynamic balance and the movement performance of the participants with dynamic valgus after doing plyometric exercises that result in subsequent improvement in their exercise performance.