Method Fifty-nine subacute hemiparetic stroke in-patients participated in this study. All patients were randomly assigned to one of two groups: the control group and the experimental group. Both groups received the same conventional physical therapies for 4 weeks. The experimental group received an additional core strengthening program (CSP). Korean mini-mental state examination (K-MMSE) and Korean Modified Barthel Index (K-MBI) were performed on admission. CSP was performed for 30 minutes a day, 3 days per week for 4 weeks. We selected nine exercises available for stroke patients, and divided them as three steps according to the degree of difficulty. Because of the muscle weakness in stroke patients, a physical therapist often helped them during exercise. Outcome measurement included trunk control test (TCT), trunk impairment scale (TIS), and Berg balance scale (BBS) and we compared both groups before and after the period of training.

Results
There were no significant differences in baseline general characteristics and initial values between the two groups. After rehabilitation therapy, both groups showed significant improvements in BBS, TIS, and TCT (p＜0.05). Following 4 weeks of therapy, changes of BBS, TIS score in the experimental group were significantly higher than those of the control group (p＜0.05). However, the change of TCT score was not significantly different.

Conclusion Analysis of different clinical parameters showed that better outcomes in BBS, TIS scores were achieved from CSP. This study suggests that CSP conducted for 4 weeks may be beneficial as a therapeutic technique for use in improvement of trunk balance in patients with subacute hemiparetic stroke.