Successful aerial rotation emerges from feedforward neuromechanical coupling rather than feedback-driven compensation

Successful execution of complex aerial maneuvers in competitive surfing depends on precise neuromuscular coordination and stable neural control strategies. Traditional assessments of movement quality often overlook the underlying organization of muscle synergies and their temporal modulation. In this work, we compare muscle synergy structure, synergy activation timing, and neuromechanical coupling between successful and unsuccessful AIR 360 trials performed by elite surfers. Eleven national-level surfers executed the AIR 360 maneuver on a stabilized support platform while surface electromyography (sEMG), three-dimensional kinematics, and ground reaction forces (GRF) were collected. Muscle synergies were extracted using non-negative matrix factorization, synergy timing characteristics were quantified using the center of activation (CoA) and full width at half maximum (FWHM), and neuromechanical coupling was assessed using regularized canonical correlation analysis (rCCA).Successful trials exhibited fewer synergies with more concentrated muscle contributions, along with earlier and more stable activation phases. In contrast, unsuccessful trials showed additional synergies and irregular activation modulation, indicating increased control dimensionality and compensatory recruitment. Neuromechanical coupling further revealed a feedforward-dominant pattern in successful trials, with neural signals leading mechanical responses, whereas unsuccessful trials demonstrated synchronous or delayed coupling, reflecting greater reliance on feedback-based control. These findings suggest that successful AIR 360 performance depends on a low-dimensional, stable synergy organization and robust feedforward neuromechanical coupling, providing new insights into the neural mechanisms that support high-level aerial rotation in surfing.