Gait Analysis of Elastic Cable Assistance: Effects of Pretension on Kinematic Gait Parameters and Muscle Activity

Abstract

Stroke-related gait impairments reduce walking ability, independence, and quality of life, creating a need for accessible rehabilitation technologies. Passive cable-driven systems may provide a lightweight and low-cost alternative to conventional robotic gait devices, but the influence of their mechanical settings on gait behavior remains unclear. This study investigated how elastic cable pretension and attachment location influence gait kinematics and muscle activity during walking with the Passive Mechanical Add-on for Treadmill Exercise (P-MATE), a passive gait rehabilitation device. Cable pretension refers to the initial tension applied to the elastic cables before movement, while two attachment configurations were evaluated for force transmission to the lower limb: a proximal cuff around the lower leg and a distal bandage around the foot. Seven healthy adults walked on a treadmill under three pretension conditions (10 N, 30 N, and 50 N) and both attachment configurations while kinematic and electromyographic (EMG) data were recorded. The 30 N pretension condition produced gait patterns closest to unassisted walking, whereas both lower and higher pretension levels caused greater deviations in step length, step width, swing velocity, and knee motion. Increasing pretension also increased step width and reduced knee range of motion. Compared to the cuff configuration, the bandage configuration produced greater step width and lower knee range of motion, suggesting stronger guidance of lower-limb movement due to distal force application. Muscle activation patterns were largely preserved, although muscle-specific adaptations were observed under higher pretension conditions. These findings demonstrate that both cable pretension and attachment location substantially influence gait behavior during walking with the P-MATE and highlight the importance of personalized device settings in passive gait rehabilitation.