Gait impairment remain one of the main problem for hemiplegic stroke patients. After the 6 first months, stroke patients are classically described with moderate or no improvement. Here, we want to compare the effectiveness of a flexor and extensor paretic knee muscular strengthening program with conventional physiotherapy delivered by the local physiotherapist of the patient, in a very ecological way.

Gait impairment remain one of the main problem for most of chronic hemiplegic stroke patients. After the 6 first months, stroke patients are classically described with moderate or no improvement for motor skills. However, physiothertapy is very often delivered to try to increase motor performance. Here, we want to compare the effectiveness of a flexor and extensor paretic knee muscular strengthening program with conventional physiotherapy delivered by the local physiotherapist of the patient, in a very ecological way. Patients will be randomly affected to one group with the same amount of physiotherapy (at least 3 times weekly for 6 weeks). Assessment will be done blindly by another physiotherapist, before, after the 6-week treatment and 6 weeks later to evaluate immediate and remaining benefits of each treatment.

Inclusion Criteria:

• Hemipegia due to ischaemic or hemorrhagic stroke more than 6 months ago
• 1st and unique cerebral lesion (Xscan or MRI)
• ability to walk 15 m with or without cane or crutch
• able to understand and give approved consent
• quadriceps at 3/5 (MRC) or stronger

Exclusion Criteria:

• Current treatment with botulinum toxin for spasticity of the paretic flexor or extensor of the knee
• Cardiovascular disease contra-indicating effort and strengthening
• Pregnancy
• Evolving pathology
• Rheumatic disease of the knee contraindicating strengthening
• Aphasia with severe comprehension impairment