Effects of Gait Modification on Lower Extremity Sagittal Plane Biomechanics

Abstract

Gait modification (GM) via real-time biofeedback (RTB) is a conservative intervention that has shown positive outcomes in post stroke and diabetic patients. Results from a recent systematic review support the effectiveness of this approach for increasing peak internal knee extension moment (iPKEM). iPKEM is a resistive moment to peak external knee flexion moment (ePKFM), which is associated with altered joint loading. Scarce information exists on the comparative effectiveness of existing GM strategies. PURPOSE: To compare the effectiveness of trunk lean (TL), medial knee thrust (MKT), and foot progression (FP) on iPKEM. METHODS: 10 healthy individuals volunteered for this study (28.4±3.8 years, 1.73±0.1 m, 75.3±12.5 kg). Mean and standard deviation (SD) for iPKEM, trunk angle, knee angle (KA), and foot angle during stance were calculated from 10 baseline trials using a motion capture system (200Hz) and force plates (1000Hz). 10 trials completed for each strategy using RTB so that joint angles fell within a determined range (1-5 SD) relative to baseline. Visual 3D (V3D) was used to project visual RTB as a line graph displaying real-time joint angle during stance. V3D was used to calculate joint angles (°) and internal moments (Nm/kgm). Participants modified their gait based on strategy so the line fell within a highlighted bandwidth representing target ranges. Repeated measures ANOVA was used to assess differences in iPKEM between strategies. Dependent t-tests were conducted to compare joint angles between baseline and modification strategy (p<0.05). RESULTS: A significant difference between strategies was attained for iPKEM (p=0.001). MKT (.53±.24) had higher iPKEM than all other strategies (Baseline: .31±.2, FP: .34±.12, TL: .31±1.4). No other statistically significant difference was found (p>0.05). CONCLUSION: MKT gait increased iPKEM despite no significant differences in KA compared to baseline. The observed increase in iPKEM during MKT gait suggests that participants were successful at attenuating ePKFM during the absorption phase of stance. Lack of significant changes in joint angles across conditions suggests that overall gait kinematics were similar for all conditions. Future research employing greater values for kinematic change is needed to further understand the effect of GM on iPKEM.