Session: 07-05-01: Dynamics and Control of Biomechanical Systems

Paper Number: 166345

Effects of Combined Fatigue and Asymmetric Loading on Knee Kinematics During
Walking Gait 

Combined fatigue and asymmetric loading are key factors that influence gait mechanics, leading to significant alterations in knee joint kinematics. This study investigates the combined effects of fatigue and asymmetric loading on walking gait by analyzing knee flexion, abduction, and internal rotation variability across different fatigue conditions. Motion capture data were collected using a Vicon motion capture system, with a modified Grood and Suntay Joint Coordinate System (JCS) applied to quantify clinical knee angles. The experimental protocol included normal walking, asymmetrically loaded walking (Farmer’s Carry), and post-fatigue trials following squat-induced fatigue (25, 50, 75, and 100 squats). The results demonstrated that fatigue progressively increased flexion variability and peak flexion angles, with the most pronounced variability occurring between heel strike and 30% of the gait cycle. While abduction and internal rotation remained relatively stable, the Farmer’s Carry condition exhibited the highest variability in frontal-plane motion, suggesting a destabilizing effect of asymmetric loading. Additionally, stride length variability increased significantly in the FC 100 Squats condition, indicating greater instability as fatigue accumulated. These findings provide insights into fatigue-induced compensatory mechanisms and the biomechanical consequences of asymmetric loading on gait stability. The increased variability in flexion and abduction under fatigue suggests greater reliance on passive joint structures, which may contribute to long-term joint stress and injury risk. Future research should focus on longitudinal studies assessing neuromuscular adaptations, metabolic efficiency, and joint loading mechanics to further understand the implications of fatigue and asymmetrical gait on musculoskeletal health. The study’s findings have direct applications in rehabilitation, injury prevention, and occupational ergonomics, where managing gait stability under fatigue is critical.

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Presenting Author: Dumitru Caruntu University of Texas - Rio Grande Valley

Presenting Author Biography: Dumitru I. Caruntu is an ASME Fellow and a Professor in the Department of Mechanical Engineering at The University of Texas Rio Grande Valley. He earned his Ph.D. in Mechanical Engineering from Politehnica University of Bucharest and an M.A. in Mathematics from the University of Bucharest. Dr. Caruntu is a licensed Professional Engineer and has been an ASME Fellow since 2019.
Dr. Caruntu has been honored with the prestigious 2023 ASME Dedicated Service Award, recognizing his significant achievements, ongoing contributions to the field of mechanical engineering, and dedication to the professional community.
His research focuses on MEMS and NEMS, nonlinear dynamics, vibrations, mathematics, and biomechanics. He has served as a reviewer for numerous prestigious journals, including the Journal of Sound and Vibration, Nonlinear Dynamics, Journal of Vibration and Acoustics, Communications in Nonlinear Science and Numerical Simulation, Mechanics Research Communications, and Medical & Biological Engineering & Computing. Additionally, he has reviewed for ASME IMECE (2004–2024), ASME IDETC (2007–2024), and ASME DSCC (2009–2020).
Dr. Caruntu has held editorial roles as an Associate Editor for several esteemed journals, including Nonlinear Dynamics, Communications in Nonlinear Science and Numerical Simulation, ASME Journal of Dynamic Systems, Measurement, and Control, ASME Journal of Computational and Nonlinear Dynamics, Journal of Mechanics-Based Design of Structures and Machines, and Shock and Vibration.

Authors:

Dumitru Caruntu University of Texas - Rio Grande Valley
Alfirio Trejo University of Texas Rio Grande Valley