Effect of an internally versus externally focused acl injury prevention program on injury risk

BACKGROUND: Anterior cruciate ligament (ACL) injury prevention programs have shown mixed results, which may be in part due to suboptimal training components. OBJECTIVE: Determine effects of a prevention program with external and internal focus of attention on (potential) biomechanical risk factors for ACL injury. DESIGN: Pretest-posttest control group. SETTING: Laboratory and field. PARTICIPANTS: 31 elite female soccer players participated. Exclusion criteria included previous ACL injury or current lower extremity injury. INTERVENTION: Two teams performed warm-up programs, including strength, agility, balance, plyometric, core and speed exercises twice a week for 12 weeks. One team received instructions to focus attention internally toward movements of the body (INT); another team received instructions to focus attention externally near the body (EXT). The control group (CON) performed their regular warming-up without specific instructions. MAIN OUTCOME MEASUREMENTS: Normalized external knee and ankle joint moments and joint angles on a two-legged jump-landing-rebound task. RESULTS: Results of 3x2 repeated measures ANOVA revealed significant group x time interaction for peak knee extension moment (F (2,23)=4.09, P=.03), the EXT group decreased more (-0.900.16 to -0.730.15 Nm/kg*m) than the CON group (