Introduction: Shock wave therapy (SWT) has a potential interest to treat spasticity. However, the pathophysiology of this treatment remains unknown. Some authors assert that it is effective on spasticity itself, while others suggest that it acts more on fibrosis.

Method: this study will assess the effectiveness of radial SWT to treat wrist and finger flexors stiffness in stroke patients, comparing subacute spastic patients (< 12 months) with chronic patients presenting muscle contractures (> 12 months). Forty-eight stroke patients (24 in the subacute phase and 24 in the chronic phase) will be included. One real and one sham sessions of SWT will be performed with a 2-week interval. The order of the sessions will be randomized. Motor control, stiffness and spasticity will be assessed with clinical and objective measures, just after and just before each session, by a blind assessor. The targeted muscles will be flexor carpi radialis, flexor carpi ulnaris and flexor digitorum profundus, and will be the same for the two session.

Inclusion Criteria:

• History of cerebral lesion
• Wrist spasticity ≥ 1+/4 on the Modified Ashworth Scale
• Wrist spasticity ≥ 2/4 on the Tardieu Scale
• Passive dorsal extension of the wrist ≥ 10°

Exclusion Criteria:

• Botulinum toxin injection in the upper limb in the past three months
• History of wrist arthrodesis
• Myopathy
• Treatment with oral anticoagulants or coagulation disease
• Tumor or infection of the paretic upper limb