Sham tDCS will be delivered by a constant-current electrical stimulator (DC-stimulator; Eldith, Ilmenau, Germany). Rectangular electrodes covered with a saline-soaked sponge will be used for the anode and cathode. The anode will be placed over the leg area of the motor cortex, on the lesioned side, with the medial border of the electrode placed laterally to Cz on the international electroencephalogram 10-20 system. The cathode will be placed above the contralateral orbit. The stimulation intensity will The stimulator will only be applied for the first and last 30 seconds.

TENS will be delivered to the common peroneal nerve of both intact and paretic leg for 30 minutes using a 120z Dual-Channel TENS Unit (ITO Physiotherapy & Rehabilittaion, Co, Ltd, Tokyo, Japan). The TENS stimulation will be at 100 Hz, with 0.2 ms square pulses at an intensity of twice the sensory threshold (defined as the minimum intensity at which subject reported feeling a tingling sensation and below the motor threshold as indicated by the absence of muscle twitching.

Placebo-TENS will be applied to identical-looking TENS devices, with the electrical circuit disconnected inside the devices. Placebo-TENS will be delivered to the common peroneal nerve of both intact and paretic leg for 30 minutes that set at 100 Hz, with 0.2 ms square pulses.

The lower-limb task-oriented training comprises 5 exercises for 30 minutes, namely stepping up and down, heel lift a dorsiflexed position, partial squatting, gait re-education and transition training.

The TUG is used to measure the functional mobility. Each subject will be required to rise from a chair with armrests, walk 3 m forward, turn around, return to the chair and sit down. The time taken to complete this task will be measured in seconds with a stopwatch. Each condition will be repeated for 2 times. The completion time will be averaged.

The lower-extremity motor coordination test is used to measure the coordination of both the paretic and intact legs. Two red flat targets will be secured on the floor 30 cm apart. In sitting position with the feet resting flat on the floor and the heels on one of the targets, the participant will be instructed to touch 2 targets alternately with the big toe, as quickly and as accurately as possible, for 20 seconds. The number of times each target is touched will be counted. The more touch times indicated a better performance.

Gait parameters will be assessed using the GAITRite system (CIR system, Inc., Havertown, Pennsylvania), a pressure-sensitive mat that automatically captures spatiotemporal gait characteristics. Participants will walk at their self-selected comfortable pace along the instrumented walkway.

BBS is a 14-item objective measure that assesses static balance and fall risk in adult patients. Items include tasks such as sitting to standing, standing unsupported, transfers, reaching, turning 360 degrees, and single-leg stance. Each item is scored from 0-4 points (0=unable to perform, 4=independent), with a maximum total score of 56 points. Higher scores indicate better balance.

The Limits of Stability (LOS) test quantifies participants' ability to intentionally shift their center of gravity (COG) to their stability limits without losing balance using Bertec Balance Advantage System (Bertec Corporation, Columbus, OH, USA). Participants stand on a force plate and shift their weight to move a cursor on a screen toward 8 targets arranged in a circular pattern at their theoretical limits of stability (100% LOS). Key parameters measured reaction time (RT) , movement velocity (MVL), directional control (DCL), endpoint excursion (EPE), maximum excursion (MXE). Higher scores indicate better dynamic balance control, except for reaction time where lower scores are better.

SOT assesses the participant's ability to maintain postural stability by evaluating the integration of visual, vestibular, and somatosensory inputs using Bertec Balance Advantage System (Bertec Corporation, Columbus, OH, USA). The test systematically disrupts sensory information while measuring postural sway.

Outcome measures include composite equilibrium score and sensory analysis ratios (somatosensory, visual, vestibular, and preference ratios). Higher scores indicate better postural stability and sensory integration.

The level of community integration will be assessed by the Cantonese version of Community Integration Measures (CIM-C). The CIM is a client-centred questionnaire with 10 items; each item rating from 1 to 5 with a total score from 10 to 50. A higher CIM-C score indicates a higher level of community integration.

FADI is a 26-item patient-reported outcome measure that assesses functional limitations related to foot and ankle conditions. The questionnaire consists of 22 items assessing activities of daily living and 4 items specific to pain. Each item is scored on a 5-point Likert scale from 0 (unable to do) to 4 (no difficulty at all). Total scores are converted to percentages, with 100% representing no dysfunction. The FADI includes activities such as walking on even/uneven ground, climbing stairs, squatting, and recreational activities.

The EQ-5D VAS is a standardized vertical visual analog scale (thermometer-like scale) that measures self-rated health status. Participants rate their overall health state on a scale from 0 (worst imaginable health state) to 100 (best imaginable health state). This scale is part of the EQ-5D instrument but specifically captures the respondent's overall self-rated health status on the day of assessment. The VAS provides a quantitative measure of health outcome that reflects the participant's own judgment.