This is an exploratory randomized trial on 45 subacute stroke subjects with gait impairment following a single anterior circulation subcortical stroke 3-6 months prior to recruitment, with comfortable walking speed of 0.2 to 0.4 m/s (which generally describes those who require 1 person assistance to supervision for ambulation - Functional Ambulatory Category (FAC) 3 (Kollen, et al. 2006). Exclusion criteria include a history of seizures, uncontrolled medical condition or psychiatric history, neglect, aphasia, or any cognitive or behavioural impairment causing inability to comply with instructions, cranial surgeries, pacemakers and other implants which preclude the use of NIBS. Subjects on psychoactive medications (eg. antiepileptics, antipsychotic and antidepressant medications) will be excluded from the study. The diagnosis for subjects' eligibility to join the study will be determined by subjects' self-report (to obtain medical history), medical records (to verify subjects' self-report) as well as assessment by the research staff in the screening session (including FMA and 10 meter walk test, ). Subjects should have completed inpatient rehabilitation and should not be undergoing any other interventions targeting lower limb recovery during the study. Subjects are allowed to continue with outpatient rehabilitation (generally not more than twice a week) and home exercise program after the active intervention phase of the study.