Knee Kinetic Asymmetry In Collegiate Athletes Post-anterior Cruciate Ligament Reconstruction: Correlations Across Common Athletic Tasks

Objective clinical assessments after anterior cruciate ligament reconstruction (ACLR) are utilized to facilitate a successful return-to-sport (RTS) and reduce re-injury risk. These assessments typically include athletic tasks such as running, jumping, or hopping. It is unclear how closely knee biomechanics during one task are associated with another. Better understanding of these relationships may improve efficiency of RTS assessments and guide exercise selection and dosage. PURPOSE: Determine the associations between knee kinetic asymmetry across tasks in collegiate athletes near RTS. METHODS: Division I collegiate athletes 8.1 ± 1.6 months post-ACLR (n = 39; 22 Female, BMI: 25.4 ± 3.5 kg/m2) completed treadmill running (4.2 ± 0.4 m/s), countermovement jumps (CMJ), and single leg vertical jumps (SLJ) while 3D kinematics and ground reaction forces (GRF) were collected. Limb symmetry indices (LSI) of peak knee extensor moments (PKEM) during the stance phase of running (Run) and the takeoff (TO) and landing (LAND) phases of the CMJ and SLJ were calculated. Pearson correlations assessed the relationship between PKEM LSI across tasks and jump phases. RESULTS: Average (± standard deviation) PKEM LSIs were: 72.0 ± 17.6% (Run), 81.3 ± 11.8% (CMJTO), 81.4 ± 14.0% (CMJLAND), 74.9 ± 16.2% (SLJTO), and 70.5 ± 16.2% (SLJLAND). Significant positive correlations were observed between PKEM of all tasks (r range = 0.54 to 0.73; all p-values<0.001; see FIGURE for specific relationships). CONCLUSION: Knee kinetic asymmetries 8 months post-ACLR are moderately correlated between running, CMJ, and SLJ. Despite significant associations between all tasks, the wide confidence intervals suggest that knee kinetic asymmetry from a single task may not be clinically useful in predicting the asymmetry in another task. As such, screening multiple tasks may be necessary to best characterize kinetic symmetry and provide individualized care near RTS post-ACLR.