This study innovatively proposes an "environment-perturbation balance training (E-PBT)" intervention, which delivers stable, graded environmental perturbations to keep the challenges within the manageable range. This approach can significantly reduce fear, align with the psychological characteristics of subacute stroke patients, and improve training engagement and safety, thereby filling the current research gap that has insufficiently addressed subacute patients and those with moderate-to-low functional levels. By altering the size and angle of the support surface, this training heightens patients' alertness and psychological adaptability, prompting them to actively integrate sensory information and adjust motor strategies. In turn, this can more effectively reshape internal model of balance control and facilitate genuine neuroadaptive learning in the brain. Moreover, this training more closely mimics real-life fall scenarios, with the aim of directly cultivating the proactive postural control and strategic decision-making abilities required in daily living.

This study aims to systematically evaluate the efficacy of this E-PBT intervention on functional recovery in patients during the subacute stage of stroke through a prospective randomized controlled trial, and to explore its potential effects on balance ability, activities of daily living, and overall functional outcomes, thereby providing a more effective and clinically translatable new strategy for post-stroke rehabilitation.

Inclusion Criteria:

• Diagnosed with stroke according to the International Symposium on Cerebral Vascular Disease criteria, with definite confirmation by imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI).
• First-ever or recurrent cerebral hemorrhage or cerebral infarction. According to the Guidelines for the Early Management of Patients with Acute Ischemic Stroke: A Guideline for Healthcare Professionals from the American Heart Association/American Stroke Association and the Chinese Guidelines for Early Rehabilitation of Stroke, rehabilitation can be initiated once the patient's condition is stable (vital signs are stable and no further progression of symptoms and signs).
• Total NIHSS score between 5 and 20 (inclusive) prior to randomization, with a lower limb motor score ≥2.
• Presence of balance dysfunction, with a miniBESTest total score ≤12.
• Good compliance with rehabilitation therapy and no contraindications to active training.
• Age between 18 and 85 years.
• The subject or their legal representative is able and willing to provide written informed consent.

Exclusion Criteria:

• History of prior cerebral hemorrhage or cerebral infarction with residual significant limb dysfunction.
• Severe cognitive impairment or sensory aphasia that precludes communication and cooperation with treatment.
• Concomitant severe cardiopulmonary, hepatic, or renal insufficiency, or other serious medical diseases.
• Presence of neurological or musculoskeletal disorders affecting balance function prior to stroke onset.
• Uncontrolled severe hypertension or diabetes mellitus.
• Active bleeding or deep vein thrombosis.
• Current participation in another clinical trial or rehabilitation program that may affect the results of this study.
• Any other condition that may interfere with the outcomes of this study.
• History of limb amputation affecting bilateral coordination or independent walking ability.
• Pregnancy.