Background: Upper extremity (UE) motor improvement post-stroke is frequently inadequate, with many individuals struggling to perform functional tasks such as reaching. Addressing this issue has prompted the use of psychometrically validated measures to quantify motor recovery and the implementation of innovative interventions to enhance UE function. Robotic rehabilitation, a leading innovation, can provide precise assessment and targeted UE therapy. However, its effectiveness critically relies on using validated measures to evaluate UE motor impairments post-stroke. Moreover, the merging of robotic devices with Functional Electrical Stimulation (FES) into hybrid rehabilitation systems has emerged as a promising method for UE rehabilitation in recent years. This dissertation aims to evaluate an end-effector robotic device, REACH, for assessing reach movement dysfunction and to determine the efficacy of a novel hybrid rehabilitation approach that integrates REACH with multi-muscle FES, aiming to improve UE reach function in individuals with chronic stroke. Methods: The first study assessed the psychometric properties (intra-session test-retest reliability, concurrent, and discriminant validity) of kinematic parameters (Smoothness, Speed, and Range) produced by the REACH device, benchmarked against the OptiTrack system among healthy adults and chronic stroke individuals. The second study tested the efficacy of a hybrid rehabilitation system, randomly assigning individuals with chronic stroke to receive either the experimental (REACH+FES) or control (REACH Alone) intervention. Outcomes were measured through clinical and kinematic measures. The clinical measures included UE-FMA, ARAT, RPSS, MAS. The kinematic measures (distance, linearity, end-error, and velocity) were captured using the Kinereach system. Results: Kinematic parameters, specifically peak speed and range, showed strong correlation with the OptiTrack system and excellent intrasession test-retest reliability, confirming their concurrent validity and reliability. Also, the REACH robot-derived kinematic measures effectively differentiated between participant groups. The randomized controlled trial (RCT) demonstrated that the hybrid REACH+multi-muscle FES intervention improved significantly than the REACH alone intervention, resulting in notable improvements in both UE impairments and function, as evidenced by the clinical (UE-FMA, ARAT) and kinematic (distance and contralateral linearity) measures. Conclusions: This dissertation confirms that the kinematic measures of peak speed and range from the REACH device are reliable and valid indicators of reach performance. It also establishes the efficacy of the hybrid REACH+multi-muscle FES system as an intervention for enhancing UE function in individuals with chronic stroke.