Age and Gender Effects on Lower Extremity Kinetics of Youth Soccer Players Performing a Stop-Jump Task

Abstract

1064 Several investigators have speculated that anterior cruciate ligament (ACL) injuries frequently occur during the stop-jump phase of movement tasks, yet minimal data exists in comparing lower extremity motion patterns between different age groups and gender performing stop-jump tasks. PURPOSE: To compare knee kinetics of male and female youth soccer players to determine if there are motion pattern differences between gender and age groups (11–16 yrs.) when performing a stop-jump task. METHODS: Knee kinetics of 30 female (age = 13.80 ± 1.76 yrs, height = 1.58 ± .09 m, weight = 49.89 ± 10.19 kg) and 26 male (age = 13.54 ± 1.79 yrs, height = 1.63 ± .11 m, weight = 52.90 ± 13.25 kg) youth soccer players were collected. Subjects took a three-step approach and performed a stop-jump maneuver to “head” an imaginary soccer ball. The dependent variables (normalized to bodyweight and height) were proximal anterior tibial shear force maximum and at initial foot contact; knee flexion (+)/extension (−) and varus (+)/valgus (−) moments at maximum proximal anterior tibial shear force and at initial foot contact during a stop-jump task. RESULTS: Preliminary analyses were performed using a stepwise multiple regression analysis on each dependent variable for age and gender effects to evaluate the motion pattern trends. A significant gender effect was found for proximal anterior tibial shear force at initial foot contact and knee flexion/extension moment at initial foot contact. Females demonstrated greater proximal anterior tibial shear force at initial foot contact and greater knee extensor moment at initial foot contact as compared to males. A significant age effect was found for knee varus/valgus moment at maximum proximal anterior tibial shear force and at initial foot contact. Younger aged youth soccer players demonstrated a smaller knee valgus moment at maximum proximal anterior tibial shear force, while older aged players demonstrated a greater knee valgus moment. Younger aged players demonstrated greater knee valgus moment at initial foot contact, while older aged players demonstrated a knee varus moment. No statistical difference was found for maximum proximal anterior tibial shear force, but the data indicate a trend that females had increased shear force as compared to their male counterparts. CONCLUSIONS: These findings suggest that age and gender differences occur in youth soccer players' lower extremity motion patterns when performing a stop-jump task. The findings of this study provide a basis for further research comparing age and gender jump-landing differences, which may be valuable for the development of noncontact ACL injury prevention programs.