Difficulties to include patients

Muscle alterations and modifications passive biomechanical properties that occur on a spastic muscle contribute to functional disorders involved in spasticity. Botulinum toxin (TB) A is the reference treatment of the focused spasticity, and muscle source structural and biomechanical changes, very little studied in humans, especially since it is not one possibility of easily and reliably paraclinical assessment injections consequences.

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