Walking with treadmill lateral oscillation facilitates paretic limb loading in individuals post-stroke

Individuals post-stroke commonly exhibit impaired weight transfer, contributing to deficits in gait and balance control. Lateral translation of the walking surface may generate inertial forces that alter body transfer towards the stance foot. This study determined the immediate effects of treadmill mediolateral oscillation walking on limb loading and weight transfer biomechanics in individuals with chronic stroke. Seventeen participants walked at comfortable speed under two conditions: with and without low-intensity mediolateral treadmill oscillation (1 cm amplitude, sinusoidal pattern). Kinetic, kinematic, and electromyographic data were collected to quantify vertical ground reaction force, weight transfer time, center of mass motion, joint torques, and muscle activity. Treadmill oscillation increased vertical ground reaction force on both the paretic and non-paretic limbs (p < 0.05) and reduced weight transfer time toward the paretic side (p < 0.05) compared to no oscillation, indicating enhanced weight transfer dynamics. These changes were accompanied by increased paretic single-leg stance time (p < 0.05) and greater mediolateral center of mass velocity and displacement (p < 0.05) during walking with treadmill oscillation. Stepwise regression revealed that increases in paretic limb loading were predicted by increases in paretic hip abduction torque and gluteus medius muscle activation, explaining 44 % of the variance. These findings demonstrate that low-intensity, continuous treadmill oscillation can facilitate limb loading and accelerate weight transfer. Treadmill oscillation walking may provide a novel, externally driven approach to enhance weight transfer and promote paretic limb use in post-stroke gait rehabilitation.