OBJECTIVE We investigated the effect of long-term practice on motor improvements in chronic stroke patients. METHODS Randomized parallel group controlled study. METHODS Motor Behavior Laboratory, University of Florida. METHODS Eighteen individuals who experienced a stroke more than nine months prior to enrolling. METHODS The treatment interventions were bilateral arm movements coupled with active neuromuscular stimulation on the impaired arm for both practice duration groups. The short-term group received one treatment protocol, whereas, over 16 months, the long-term practice group completed 10 treatment protocols. All protocol sessions were 6 hours long (90 minutes 1 day/week/4 weeks) and were separated by 22 days. METHODS Repeated data collection on three primary outcome measures (i.e. Box and Block test, fractionated reaction times, and sustained force production) evaluated motor capabilities across rehabilitation times. RESULTS Mixed design ANOVAs (Group × Retention Test: 2 × 4; Group × Retention Test × Arm Condition: 2 × 4 × 2) revealed improved motor capabilities for the long-term practice duration group on each primary measure. At the 16-month delayed retention test, when compared to the short-term group, the long-term group demonstrated: (a) more blocks moved (43 v 32), (b) faster premotor reaction times (158 v 208 ms), and (c) higher force production (75 v 45 N). CONCLUSIONS Sixty hours of rehabilitation over 16 months provided by various bilateral arm movements and coupled active stimulation improved motor capabilities in chronic stroke.