tDCS
Each participant was randomly assigned to the Active or Sham tDCS group prior to the first experimental session without the participant’s knowledge. They remained in the same group for all 4 study sessions (parallel, single-blinded). The tDCS was applied at the “M1 hotspot”, which was determined for each participant in a separate preliminary session. In the preliminary session, transcranial magnetic stimulation (TMS) was applied to elicit the soleus MEP during standing, using Magstim 200Bipolar tDCS was delivered using a Soterix MXN-9 stimulator (Soterix Medical Inc., New York, NY) at 2 mA with rubber electrodes encased in 5 × 7 cm saline soaked sponges (0.06 mA/cmFor Active tDCS, 30 s of current ramp-up and 30 s of ramp-down were incorporated in the first and thirtieth minutes of the 30 min of tDCS (i.e., 29 min of constant 2 mA stimulation between the ramp-up and ramp-down periods). For Sham tDCS, the current was ramped up to 2 mA over 30 s and then immediately ramped down to 0 mA over the next 30 s, in the first and thirtieth minutes (i.e., 28 min of no stimulation between ramps). These Sham parameters have been shown to have no significant effect on corticospinal excitability while replicating the sensations of Active stimulation (Gandiga et al. 