Kinematic Assessment of ACL Injury Risk and Performance During 90° Change-of-Direction Maneuvers

OBJECTIVES This study investigated the kinematic characteristics associated with high performance and a lower risk of anterior cruciate ligament injury during 90° change-of-direction (COD) maneuvers.METHODS While 34 male basketball players performed pre-planned 90° COD trials, kinematics were recorded using a 10-camera markerless motion capture system (120 Hz). Hip, knee, and trunk angles during weight acceptance were analyzed, as were center-of-mass velocities. Associations with knee abduction angle and completion time were tested with correlation analyses. Participants were subsequently stratified based on a composite score into the Fast & Low-Risk (F&L) and Slow & High-Risk (S&H) groups for between-group comparisons.RESULTS Knee abduction angle was correlated with trunk lateral flexion (r = −0.423), trunk rotation (r = −0.613), hip abduction (r = −0.589), and hip internal rotation (r = −0.637). Completion time was correlated with approach velocity (r = −0.640), exit velocity (r = −0.724), maximum running velocity (r = −0.479), and deceleration rate (r = 0.526). Compared with the S&H group, the F&L group were found to have smaller knee abduction angles (3.06 vs. 9.49°) and shorter completion times (1.50 vs. 1.68 s), with higher approach (5.38 vs. 4.58 m·s−¹) and exit (4.34 vs. 3.77 m·s−¹) velocities, lower deceleration rate (28.61 vs. 36.47%), less trunk extension (–17.69 vs. –21.57°), and greater trunk rotation (27.12 vs. 15.84°) toward the cutting direction. The maximum running velocities did not differ significantly among groups (6.20 vs. 6.05 m·s−¹).CONCLUSIONS For 90° COD, higher approach and exit velocities with limited velocity loss and trunk rotation toward the cutting direction were associated with shorter completion times and smaller knee abduction angles. These findings outline a movement strategy that might mitigate the traditional performance–injury tradeoff and guide training that emphasizes limitation of velocity loss and trunk–hip alignment.