Altered Neuromuscular Control and Beta-Band Cortical Compensation During Gait in Sarcopenia: An Exploratory Study.

Sarcopenia is an age-related condition characterized by a decline in skeletal muscle mass and function, leading to impaired mobility and an increased risk of adverse health outcomes. However, the neuromuscular mechanisms underlying gait dysfunction in sarcopenia remain incompletely understood. In this study, individuals with sarcopenia and age-matched healthy controls were recruited. Gait parameters were assessed using a motion capture system and quantified through spatiotemporal analysis, muscle activity was evaluated using surface electromyography (sEMG) with phase-specific activation metrics, and cortical activity was measured using electroencephalography (EEG) and further analyzed using spectral analysis and partial directed coherence (PDC)-based graph-theoretical measures to assess frequency-specific functional connectivity. Individuals with sarcopenia exhibited significantly reduced gait speed and shorter step length, along with prolonged loading response and pre-swing phases. Among the recorded muscles, the tibialis anterior (TA) showed significant alterations, characterized by an increased and earlier first activation peak and a reduced and delayed second peak during the gait cycle. Phase-specific analysis revealed increased TA activity during the loading response phase and decreased activity during the pre-swing phase. EEG analysis revealed beta-band-specific alterations, with increased node strength and node degree in the frontal and central regions and elevated node strength in the parietal region, while no significant differences were observed in the delta, theta, alpha, or gamma bands. These findings suggest that sarcopenia is associated with neuromuscular alterations. The coexistence of increased beta-band functional connectivity strength and persistent gait impairment may reflect inefficient compensation, in which increased neural recruitment does not fully restore gait function. These results highlight the importance of targeting neuromuscular coordination in rehabilitation.