Inclusion Criteria1. first-ever unilateral stroke with more than 3 months onset ;
2. an initial UL subsection of the Fugl-Meyer Assessment score of 18 to 56 indicating moderate to severe and moderate UL movement impairment;
3. no excessive spasticity in any of the joints of the affected UL (shoulder, elbow, wrist, fingers);
4. be able to follow study instructions and perform study tasks;and
5. willing to provide written informed consent.
Exclusion Criteria1. with neural or psychological medical problem that may influence the study;
2. with severe joint pain;
3. with upper limb fracture within 3 months;
4. participation in any experimental rehabilitation or drug studies during the study period; and
5. refusing to provide written informed consent.