The progression of therapy with robotic devices has been continuously adapted by varying the guidance force, decreasing assistance, increasing resistance, expanding the movement amplitude, and increasing the quantity of volitional movement [2]. Another theoretical advantage of robots is the possibility they provide to measure kinematic (related to the description of movements) and kinetic (related to the forces and torques causing the movements) parameters associated with arm movements during therapy, a feature stated as key for a continuous objective assessment of motor functions [6]. For some of these parameters, the therapists selected the limits within which the patient and robot will cooperate, such as the maximum working volume of reachable space or the maximum weight support that the robot can provide [1,7]. In manual rehabilitation, the therapist could provide a semiquantitative evaluation of the patient's participation at his/her own rehabilitation [8], but the robot can quantify the physical parameters, obtaining a more objective assessment. In fact, most robotic systems allow therapists to calibrate the working space according to the patient's mobility, providing a quantitative assessment of specific movement parameters such as resistance, strength, range of motion and coordination, allowing proper adjustments of the level of difficulty for each patient during the entire recovery process [9]. In the field of robotic-assisted rehabilitation, parallel mechanisms guide the anatomic limb and the exoskeleton, two interconnected kinematic chains [10]. Robots not only could measure upper limb joint ranges of motion (ROM) but could also combine them to evaluate the volume of the working space, both in passive and active conditions. Although volume could be more interesting during active movements, the exploration of the space by the patient could be affected not only by motor deficits, but also by cognitive and sensory ones. For this reason, the working volume is often passively assessed under the guidance of a robot or therapist and used during therapy as a reference parameter [11; 12; 13]. Another important assistive aspect of robotic therapy is the weight support, usually implemented using powered or spring-based exoskeletons [9]. These last two parameters (working volume and weight support) could strictly be intertwined during the execution of tasks: increasing the amount of weight compensation has been shown to increase range of motion and decrease muscle activation, decoupling flexor synergies after stroke [9,14]. Both used during therapy as reference values, these parameters could theoretically provide important information about the progression of therapy, as proposed for the step length and body weight support in lower limb robotic rehabilitation [15]. However, the definition of working volume may depend on several factors. From a biomechanical point of view, the working volume depends on the joint ROMs. From a bioengineering point of view, the ROMs of the exoskeleton joints could define the limits of human movement. From a clinical point of view, the patient joint's passive ROMs could depend on the presence of contractures, spasticity, or pain. These clinical features are also taken into account from a therapeutic point of view when the therapist sets the working volume, moving the upper limb according to the patient's residual mobility. The working volume and weight support are set by the therapist during the initial calibration of the system and being strictly related to the clinical status of the patient, could be useful to quantify the deficits, as for passive ranges of motion [11; 13] and the body weight support of lower limb in robotic gait rehabilitation [12]. Despite the importance of working volume, related ROMs and weight support, an analysis of the relationship between these values and the clinical status of the patients is still lacking.