Background There are not many studies about treatment of shoulder spasticity.Although botulinum toxin injection has been reported to be effective for shoulder spasticity,the effectiveness was judged by pain and limited motion change,but not the spasticity itself.Shoulder spasticity is considered to play an important role in hemiplegic frozen shoulder.However,the subscapularis muscle,unlike the pectoralis major muscle,is located deep beneath scapula,where conventional injection is difficult to perform.As extracorporeal shock wave therapy (ESWT) has been reported to be effective for spasticity relief,and we thought spasticity of subscapularis muscle located deep beneath the scapula would be a good candidate for ESWT treatment.This study was to evaluate the beneficial effects of radial ESWT (rESWT) on spastic subscapularis muscle in stroke patients.Methods This is an uncontrolled,prospective,unicenter,clinical pilot study.Stroke patients (n=57; mean age 55.4years) with spastic shoulders were recruited between June 2011 and February 2012 at the University Rehabilitation Hospital.rESWT was administered to each patient every two or three days for two weeks (five total treatments).Evaluation consisted of 11 measurements for each patient; at the start of each of the five treatments and once per week during the following six weeks.Spasticity was measured at extal rotator muscles of the shoulder using the modified Ashworth scale (MAS),and passive range of motion (ROM) of the shoulder in extal rotation was recorded.Pain was measured using a visual analogue scale (VAS) during passive ROM of the shoulder in extal rotation,and was additionally recorded for patients who preserved cognitive and communicative ability (Pain group).Results Reduction in MAS and VAS and improvement of ROM during and after rESWT treatments were prominent compared to baseline.The reduction in MAS and VAS and improvement of ROM continued four weeks after the last treatment and the effects of the treatment decreased afterward.Conclusion rESWT will be able to provide stroke patients with an effective and safe procedure for the reduction of spasticity and pain as well as for the improvement of ROM of spastic shoulders.