Post-stroke spasticity is a common complication affecting the neurological recovery, self-care daily activities and patients' quality of life. Extracorporeal shock waves (ESWT) have been proven therapeutic effects on decreasing spasticity and regaining function. Stroke patients often suffer ankle plantar flexor spasticity with poor ankle movement control, leading to abnormal gait patterns and risk of falling; local pain appears as well in the ankle. Research showed application of ESWT to lower extremity spasticity reduced ankle plantar flexor spasticity, ankle pain and increased the range of ankle motion. However, the current study did not investigate the effect of ESWT on different muscles in patients with post-stroke ankle spasticity. Therefore, this study will compare the effect of focused ESWT on combination of the gastrocnemius and soleus muscles to gastrocnemius muscle alone in the post-stroke ankle plantar flexor spasticity.