Does achieving gait symmetry during split-belt adaptation reflect corticospinal involvement in stroke survivors?

This study explored the relationship between gait parameters [i.e., center of mass-center of pressure (CoM-CoP) angle, step length, and double-support time] and corticospinal activity in stroke survivors across two phase types: final symmetry during late adaptation (LA) and changes from baseline to LA. Twenty-two stroke survivors participated in the study. Gait adaptation was assessed using three-dimensional motion analysis and surface electromyography to measure muscle activity and movement patterns. Recordings were obtained from the bilateral tibialis anterior (TA), soleus (SOL), and medial gastrocnemius (GAS) muscles. Intermuscular coherence in the beta band between the bilateral TA muscles was quantified. Stroke survivors who reestablished CoM-CoP angle symmetry during the LA phase exhibited strong interdependence between the affected and unaffected TA signals, reflecting enhanced neural coordination. These findings suggest that changes in CoM-CoP angle symmetry are more closely linked with neural gait control mechanisms than step length or double-support time.NEW & NOTEWORTHY This study highlights the significance of the center of mass-center of pressure (CoM-CoP) angle after adaptation as a parameter for assessing walking symmetry in stroke survivors. Our results suggest that CoM-CoP angle symmetry during gait adaptation tasks may reflect inhibitory mechanisms in the corticospinal tract. Moreover, this finding emphasizes the importance of precise temporal control of whole body movements for maintaining effective gait patterns.