Inclusion Criteria- A first stroke older than nine months (acute phase and subacute stroke).
- Hemiplegia cerebral vascular following this stroke.
- Hemiplegia with an overall motor deficit plegic lower limb muscle testing level less than or equal to 3 and associating a localized spasticity lower plegic member, on the plantar flexors, assessed by the upper Ashworth Scale or equal to 1 with an injection of botulinum toxin indication of the sural triceps.
- written consent.
Exclusion Criteria- Old stroke with motor impairment of the lower limb in the chronic stage.
- Concomitant muscle disease (eg myopathy, myositis ...).
- Patients who already received a botulinum toxin injection into the gastrocnemius muscles.
- Subjects with defibrillator