Association Between Ankle Kinematics And Knee Kinetics During Landing In Individuals With ACL Reconstruction

Abstract

The single leg hop for distance (SLH) test has been reported to have high test-retest reliability and is used as a return to sport (RTS) criteria post-injury. The use of wearable technology (inertial measurement units, IMUs) may provide an improved metric with RTS decision making following anterior cruciate ligament reconstruction (ACLR), however, the reliability of an IMU device during the SLH has not yet been investigated. PURPOSE: To determine the test-retest reliability in tibial acceleration metrics (PA: peak acceleration, TPA: time to peak acceleration, AS: acceleration slope) during SLH with a between test time interval of 7-14 days in healthy collegiate soccer players. METHODS: Twenty-four collegiate soccer players (20M,4 F; 19.5 ± 1.2 yrs) granted informed consent and performed three SLH trials bilaterally (D: dominant, ND: non-dominant leg) while wearing a lightweight IMU (9.5g, 1500 Hz) fixated with a silicon strap 3-cm proximal to both medial malleoli. A custom Matlab script processed triaxial acceleration data from the maximum hop distance trial from both days with a 60-Hz, fourth-order, dual-pass Butterworth filter before resultant acceleration was computed. Legs (D, ND) were treated independently prior to intraclass correlation coefficients (ICCs), standard error of measurements (SEMs) and minimum detectable change (MDC95%) being subsequently determined. Subsequently, paired t-tests were utilized to evaluate for significant differences between test days for both D, ND legs respectively. A significance level of 0.05 was set apriori. RESULTS: ICCs for hop distance and PTA revealed good test-retest reliability (0.86, 0.78) and moderate reliability for TPA and AS (0.50, 0.74). SEM and MDC95% for PTA was 4.04g and 5.66g respectively. No significant differences (p-values: 0.64-0.90) were found within either leg (D, ND) when comparing hop metrics between testing days. CONCLUSION: IMU devices provide good test-retest reliability for PTA during SLH functional testing. Their use may be considered as an added metric for monitoring athlete progress and determining readiness for RTS after ACLR. Future testing should evaluate normative symmetry values in tibial acceleration metrics during SLH.