Combined effects of motor imagery and tendon vibration on corticospinal excitability.

Motor imagery (MI) engages neural networks involved in movement execution and modulates corticospinal excitability (CSE). Proprioceptive inputs associated with movement may further influence corticospinal engagement during MI. Tendon vibration (TV) provides proprioceptive stimulation without requiring actual movement and has also been shown to increase CSE. This study investigated whether combining MI with TV enhances corticospinal excitability and whether these effects are reproducible across sessions. Sixteen healthy participants (11 males; 24.9 ± 6.3 years) completed two similar sessions. Transcranial magnetic stimulation was used to elicit motor-evoked potentials from the wrist muscle under four conditions: rest (REST), MI of maximal wrist flexion, TV applied to the wrist, and the combination of both MI and TV (MITV). CSE was quantified during each condition as the area under the recruitment curve, obtained by progressively increasing TMS intensity. The MITV condition led to a significantly greater increase compared to REST, MI, and TV (P < 0.001). Specifically, MITV showed a 80% greater increase in CSE compared with MI. In addition, the TV and MI conditions both exhibited greater CSE than REST. Reproducibility analysis revealed poor to good reliability across sessions. Results suggest that combining MI with TV may enhance corticospinal engagement compared with MI alone.