Sex specific motor learning strategies: implications for ACL injury prevention.
Context: Retention of learned motor skills is superior when subjects adopt an external focus. Objective: Determine the effects of an internal focus (IF) and an external focus (EF) on movement patterns during sidestep cutting in females and males. Design: Descriptive cohort study. Setting: Controlled laboratory setting. Patients or Other Participants: Ninety (45 females, 22.33±3.69years, 175.96±6.71cm, 67.78±8.44kg; 45 males, 24.90±4.61years, 190.88±6.66cm, 82.26±8.52kg) experienced basketball athletes were randomly allocated to one of the three groups: control (CTRL), internal focus (IF) and external focus (EF), with 15 females and 15 males in each group. Interventions: Subjects performed sidestep cutting maneuvers in three sessions. In session 1 (S1), feedback was provided to the EF (watching own best performance) and IF (receiving verbal instructions) groups after every successful sidestep trial. This training session was followed by two retention sessions at one week (S2) and four weeks (S3) after S1, without any feedback. To determine differences between groups (CTRL, IF and EF), sessions (S1, S2 and S3) and sex (female and male), a 3x3x2 repeated measures ANOVA was conducted, followed by post hoc comparisons (Bonferroni) with α≤0.05 set a priori. Main Outcome Measures: 3D kinematics and kinetics at time of peak valgus/varus moment. Moments expressed as external moments. Results: Males in the EF group had greater vGRF (S1: 25.35±3.07N/kg, S2: 25.79±2.94N/kg, S3: 25.19±3.16 N/kg) compared to the male IF (S1: 20.55±3.79N/kg, S2: 20.78±3.73N/kg, S3: 20.56±3.52N/kg), male CTRL (S1: 21.69±3.34N/kg, S2: 21.99±4.01N/kg, S3: 22.45±3.10N/kg).