Objective: Detailed mechanisms underlying neural control of bilateral ankles during repetitive ankle movements are still unknown. The aim of the present study was to investigate how the neural properties were different between in-phase and antiphase repetitive bilateral ankle movements. Methods: Fifteen healthy young adults participated in the study. The participants performed in-phase (move the bilateral ankle simultaneously) and anti-phase (move the bilateral ankle alternately) repetitive ankle movements tasks in randomized order. Single or paired TMS (ISI=2ms, for measuring short intracortical inhibition: SICI) was delivered at hotspot which both motor-evoked potential (MEP) of the right tibialis anterior muscle (TA) and the soleus muscle (SOL) were detected in left primary motor cortex, when EMG of right TA were on-set and off-set condition during ankle movements tasks. Results: In off-set condition, The MEP amplitude of the SOL during antiphase task was significantly larger than that during inphase task. There were no significant diff erences between tasks in the MEP amplitude of the SOL at on-set condition and the TA in both conditions, and SICI in both conditions of TA and SOL. Conclusion: Neural property of the repetitive movement was prominent during antiphase movement of the ankles. These results suggest that the properties of phase during repetitive movement of the bilateral lower limbs might be considered in rehabilitative interventions.
