Inclusion Criteria:  unilateral ischaemic or haemorrhagic stroke (documented with clinical examination and neuroradiological findings) presence of spasticity at lower limb muscles, at least grade 1+ in the modified Ashworth Scale 3. age ≥ 18 years  Exclusion Criteria:  inability to walk before stroke presence of severe cognitive impairment presence of other musculoskeletal, neurological or cardiopulmonary impairment which can interfere with clinical findings presence of skin lesions that can contraindicate BoNT-A treatment previous surgical myotendinous elongation