Relationship Between Knee Valgus Asymmetry During Running And Side-Step Cutting Mechanics in Female Lacrosse Players.

Abstract

PURPOSE: Female athletes have a greater incidence of Anterior Cruciate Ligament (ACL) injuries than their male counterparts. Noncontact injuries are primarily responsible for ACL injuries in female lacrosse players. Side-step cutting (SSC) maneuvers are a common injury mechanism and it involves sudden changes in direction with acceleration or deceleration of the body. Dynamic knee valgus (KV) is an important biomechanical risk factor for ACL injuries during running and SSC but the relationship between KV asymmetry during running and kinetics related to ACL injury during SSC has not been identified. The purpose of this study was to compare ACL loading kinetics during SSC in female lacrosse players with symmetrical and asymmetrical KV during running. METHODS: Twenty-seven healthy female lacrosse athletes were classified in two groups (asymmetric: n=13 and symmetric: n=14) based on dynamic KV Symmetry Angle during a 3D analysis of running on an instrumented treadmill. Peak vertical ground reaction force (VGRF) and knee abduction moment (KABM) of the right limb were measured during right SSC to 45 degrees. Comparisons were made between the two groups for VGRF and KABM using Student’s t-test(α=0.05). RESULTS: The asymmetric group had significantly higher VGRF (2.42±0.73 vs. 2.18±0.36*BW, p=0.01) and KABM (-0.82±0.35 vs. -0.80±0.6 Nm/kg, p=0.003) during SSC. CONCLUSIONS: There is a suggestive relationship between KVA asymmetry during running and the magnitude of VGRF, KABM during SSC. Imbalances in knee kinematics during running could potentially be used as a screening tool to detect abnormal ACL loading kinetics during dynamic tasks like SSC.