Introduction:
To evaluate the efficacy and maintenance of extracorporeal shockwave therapy (ESWT) in sub-acute and chronic post-stroke spasticity patients in the Suez Canal region.

Methods:
An interrupted time series study was conducted; 82 patients were recruited in accordance with the defined inclusion and exclusion criteria. They were divided into 2 subgroups depending on the stroke duration: a sub-acute group (35 patients) and a chronic group (47 patients). ESWT was applied over knee and ankle flexor muscle belly with the following setup parameters: energy: 0.068–0.093 mJ/mm; frequency: 5 Hz; number of shots: 1500. Modified Ashworth score, clonus score, 3-minute walk test, range of motion angle of both knee and ankle joint, and Fugl-Meyer Assessment were established at baseline, after the 1^st session, and at the 1^st, 4^th, and 8^th week for the 2 groups.

Results:
Regarding the sub-acute group, there was a statistically significant improvement in the modified Ashworth score, clonus score, 3-minute walk test, and range of motion angle of both knee and ankle joint after the 1^st session and after the 1^st week of intervention. The differences were not statistically significant after 4^th or 8^th week. The chronic group showed no statistically significant improvement after the 1^st session or in the 1^st, 4^th, or 8^th week assessment.

Conclusions:
ESWT was more effective in treatment of spasticity in patients with sub-acute stroke compared with those with chronic stroke.