Many patients who have sustained strokes are unable to effectively use their hemiparetic upper extremity. Limited mobility in the performance of daily activities, such as eating or dressing, adversely affects their quality of life and compromises independence. Rehabilitation techniques engaging the hemiparetic limb in repetitive task practice (RTP) may improve upper extremity function and quality of life in patients with stroke, but costs limit the number of patients that can utilize this type of therapy. Advances in microprocessor design and function make the use of an assistive device as an adjunct to RTP plausible. An innovative assistive repetitive motion (ARM) device using an "air muscle" has been developed specifically for the rehabilitation of the hemiparetic upper extremity. The primary aim of the proposed study is to collect pilot data to estimate the clinical effectiveness of using the ARM device in conjunction with RTP to improve upper extremity motor function and the quality of life of patients with stroke. Twenty sub-acute (3 to 9 mos. post-stoke) patients will be randomized to a RTP only or ARM + RTP group. The RTP group will receive 15 days (4 hours per day) of intensive one-on-one RTP therapy. The ARM + RTP group will use the ARM device for 2 hours per day and receive 2 hours of intensive RTP per day for 15 days. Clinical motor function and quality of life measures will be taken before and after the interventions and two months later. We hypothesize that the ARM + RTP group will exhibit greater improvements in motor function and quality of life measures than the RTP only group.