Post-stroke reorganization of gait-related functional muscle networks

Post-stroke gait impairment is associated with altered muscle coordination. Understanding how functional muscle coordination contributes to joint control is essential for clarifying the mechanisms of gait impairment after stroke. Functional muscle network approaches quantify how muscle interactions contribute to joint kinematics. We investigated how gait-related functional muscle networks are reorganized after stroke and how this reorganization relates to motor impairment and gait dysfunction. Thirty-five participants with subacute stroke and 25 healthy controls underwent gait analysis using surface electromyography and lower-limb kinematics. We quantified functionally similar (redundant information), complementary (synergistic information), and independent (unique information) muscle interactions underlying joint kinematics. Participants with stroke exhibited greater redundant information and lower independent information than healthy controls. Stroke-specific functional muscle network modules emerged through merging modules observed in healthy controls. Stroke-specific module activation was also associated with motor impairment and gait performance. Overall, these findings identify a shift toward more redundant muscle coordination and stroke-specific reorganization of functional network modules, providing new insights into post-stroke gait dysfunction.