Inclusion Criteria:  diagnosis of first-ever stroke with unilateral lesion for more than 6 months demonstrating calf muscle spasticity as indicated by modified Ashworth scale equal to or greater than 1 with passive ROM of ankle dorsiflexion at least to neutral position (defined as 0°) ability to walk at least 10m independently without a walking device or ankle-foot orthosis (AFO) sufficient cognition (mini-mental state examination, MMSE score of 24 or higher)  Exclusion Criteria:  contraindications to nerve conduction tests other orthopedic and neurological disorders interfering participating in the study