Modular control of gait under visual deprivation using muscle-mode UCM analysis of COM and foot trajectory

Human walking relies on modular neural control that coordinates many muscles into low-dimensional muscle modes (M-modes). Using uncontrolled manifold (UCM) analysis, we assessed whether these modules stabilize swing-phase task outcomes and which outcome, COM motion or swing-foot trajectory, is prioritized with and without vision. Ten healthy adults walked on a treadmill under full vision (FV) and no vision (NV) conditions.

EMG signals were factorized to extract M-modes, and a mode-based UCM analysis quantified variance components and synergy strength (\(\Delta _\)) for COM and foot trajectories. Four M-modes were consistently identified across conditions. Synergy strength remained positive for both performance variables and visual conditions throughout swing phase, indicating stabilization by modular coordination.

No overall main effects of vision condition or performance variable on \(\Delta _\) were found, but phase (p