The influence of anticipation on lower extremity biomechanics during cutting: A gender comparison

Female athletes tear their ACL approximately 6 times more often than their male counterparts. Most laboratory studies evaluating gender specific biomechanical risk factors for ACL tears have done so under anticipated conditions. Whether females and males behave similarly under anticipated and unanticipated conditions is not known. The purpose of this study was to evaluate gender differences in frontal plane knee kinematics and kinetics during both anticipated and unanticipated side-cutting tasks in post-pubertal soccer players. Thirty-six healthy soccer players between the ages 14 and 18 (17 male, 19 female) participated. Lower extremity kinematics (8-camera Vicon System; 120 Hz) and kinetics (AMTI force plate; 2400 Hz) were quantified as subjects performed a side-step cutting maneuver under anticipated and unanticipated conditions. Gender differences in peak knee valgus moment and peak knee valgus angle were evaluated using two-way ANOVA and t-tests. During anticipated conditions, females exhibited higher knee valgus moments and angles than males. During unanticipated conditions however, males exhibited higher knee valgus moments and angles than females. These results suggest that assessing at-risk behavior for ACL injury is dependent on the testing methodology. Future studies evaluating gender differences in lower extremity mechanics should incorporate both anticipated and unanticipated conditions to assess fully at-risk behavior.