The overall aim of this study is to establish the clinical- and cost-effectiveness of the arm-hand BOOST therapy when delivered on top of the usual care program in the sub-acute phase post stroke and to perform a process evaluation. In this phase III RCT, 80 patients with stroke will be recruited from two inpatient stroke rehabilitation wards in Belgium and randomized to the experimental group receiving arm-hand BOOST therapy or the control group receiving the L-BOOST intervention, on top of their usual inpatient care program. The arm-hand BOOST program (1 hour/day, 5x/week, 4 weeks) consists of group exercises based on four key aspects, namely neurophysiology, sequences of reaching and grasping, de-weighting of the arm, and orientation of the hand towards objects. Additionally, technology-supported upper limb therapy will be provided two times 30 minutes per week. The L-BOOST intervention comprises a dose-matched program of lower limb exercises and general reconditioning. At baseline, after 4 weeks of training, 3 months after the intervention and at 12 months post stroke, outcome assessment will be performed. The primary outcome measure is the action research arm test (ARAT). Secondary outcomes include measures in the domain of upper limb function and capacity, independence, participation and quality of life. Multivariate ANOVA and sensitivity analyses will be used to compare change from baseline between groups. Information on medical costs will be collected to allow a health economic evaluation. Finally, a process evaluation will be performed to assist in identifying why arm-hand BOOST succeeds or fails unexpectedly or has unanticipated consequences, and how this can be optimized. At the start of this study the investigators hypothesize that: (I) Aha BOOST will result in a significant greater improvement in arm-hand activity post-intervention, at follow-up and 12 months post stroke compared to control therapy (L-BOOST); (II) Aha BOOST will result in a significant greater improvement in upper limb function, performance, independence and activity of daily living, and participation post-intervention, at follow up and 12 months post stroke. (III) Investing in 24 hours of extra arm-hand therapy to subacute stroke patient in the inpatient rehabilitation setting can reduce the health-economic and societal cost 12 months post stroke.