Differences in Knee Angle Variability and Shear Force Control Variability After ACL Injury and Reconstruction
Advisor Information
Brian A. Knarr
Presentation Type
Poster
Start Date
26-3-2021 12:00 AM
End Date
26-3-2021 12:00 AM
Abstract
INTRODUCTION: To better understand increased injury risk in individuals with anterior cruciate ligament deficiency (ACLD) and reconstruction (ACLR), previous studies have utilized nonlinear analysis to detect subtle but important changes in neuromuscular function that may not be detected using traditional measures. These studies have shown that both knee flexion angle variability and shear force control variability are altered in individuals with ACLD and ACLR. However, these outcomes have not been evaluated in the same pool of subjects, meaning it is not yet known how these alterations present together. PURPOSE: To determine changes in knee flexion angle variability and shear force control variability in individuals with ACLD and ACLR. METHODS: 4 ACLD, 4 ACLR, 4 soccer players, and 4 controls each completed a walking task and a force control task. Knee flexion angles from the walking task were recorded using 3D motion capture and force profiles from the force control task were recorded using force plates. Lyapunov exponents were calculated from knee flexion angles and force profiles for each limb. Differences in Lyapunov exponents between participant groups were evaluated using one-way ANOVAs and Kruskal-Wallis tests. RESULTS & DISCUSSION: Knee flexion angle variability was greater in ACLD subjects compared to ACLR and uninjured controls while shear force control variability was greater in ACLD and ACLR subjects compared to uninjured subjects. This indicates that shear force control variability may remain impaired following ACLR while knee flexion angle variability may be restored through surgery.
Scheduling Link
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Differences in Knee Angle Variability and Shear Force Control Variability After ACL Injury and Reconstruction
INTRODUCTION: To better understand increased injury risk in individuals with anterior cruciate ligament deficiency (ACLD) and reconstruction (ACLR), previous studies have utilized nonlinear analysis to detect subtle but important changes in neuromuscular function that may not be detected using traditional measures. These studies have shown that both knee flexion angle variability and shear force control variability are altered in individuals with ACLD and ACLR. However, these outcomes have not been evaluated in the same pool of subjects, meaning it is not yet known how these alterations present together. PURPOSE: To determine changes in knee flexion angle variability and shear force control variability in individuals with ACLD and ACLR. METHODS: 4 ACLD, 4 ACLR, 4 soccer players, and 4 controls each completed a walking task and a force control task. Knee flexion angles from the walking task were recorded using 3D motion capture and force profiles from the force control task were recorded using force plates. Lyapunov exponents were calculated from knee flexion angles and force profiles for each limb. Differences in Lyapunov exponents between participant groups were evaluated using one-way ANOVAs and Kruskal-Wallis tests. RESULTS & DISCUSSION: Knee flexion angle variability was greater in ACLD subjects compared to ACLR and uninjured controls while shear force control variability was greater in ACLD and ACLR subjects compared to uninjured subjects. This indicates that shear force control variability may remain impaired following ACLR while knee flexion angle variability may be restored through surgery.