THE EFFECTS OF PLYOMETRIC TRAINING INTERVENTION ON VALGUS AND VARUS KNEE MOVEMENT

M. Schaack, M. Aylward, J. Styner, J. Savage Lewis-Clark State College, Lewiston, ID PURPOSE: To determine if a six-week plyometric training intervention would significantly decrease valgus knee movement in post-pubescent, adolescent females. METHODS: Eighteen female subjects, ages 13-17, participated in pre- plyometric training intervention testing consisting of a 5-minute warm-up on a cycle ergometer, followed by 3-max vertical jumps using a Vertec™. Reflective markers were placed on the following right and left anatomical locations: anterior superior iliac spine (ASIS), center of patella, and lateral malleolus of fibula. Both pre- and post-testing max vertical jumps were recorded using a digital camera and analyzed using Kinovea™ software to identify valgus angles. Prior to post-testing, all participants completed a six-week (3 days/week) plyometric intervention program. Throughout training sessions, participants were provided specific coaching cues in order to reduce valgus motion, as well as other incorrect mechanics. Training consisted of similar exercises: depth jumps, jump and reach, power skips. Intensity increased throughout training. Following the six-week plyometric training intervention, participants completed post-testing, consistent with pre-testing methods. Data were analyzed using an alpha value ofp\u3c 0.05. RESULTS: Significant differences were present in valgus knee angles, p= 0.001. Means were calculated for pre- (M = 27.9 degrees) and post- (M = 12.9 degrees) valgus angles. There were no significant differences in participant max vertical jumps ( p= 0.430). Means were calculated for pre- (M = 16.03 inches) and post- (M = 16.67 inches) max vertical jump height. However, 12 of 18 (66.7%) participants increased their vertical jump height. CONCLUSION: The results propose that the plyometric intervention training had a significant decrease on valgus knee angles, but did not significantly increase vertical jump height. Supported by LCSC Internal Research Grant