This paper presents an analysis on the suitability of a low cost motion capture system to support the development of generic applications within medical scenarios. In this study we used the Microsoft Kinect (first generation) sensor as basic technology for its wide availability and the relatively low cost, which generated great interest of the scientific community in several application fields. Most of the studies found in literature however, do not address the quality and reliability of the raw data (objects position and depth) considering only the results of the integrated 3D recognition algorithms for the final skeleton/gesture analysis. This can be critical in rehabilitation, in which the knowledge of accuracy, reliability and performance in tracking patient body movements is required and assessed. To this aim, this article proposes an experimental protocol to analyze the Kinect measurement capabilities, via the definition of peculiar parameters. Here we also introduced an analysis of performance versus usage time. Results showed some weaknesses of the sensor. Specifically, resolution was found in the range of tens of millimeters while degrading over time. The adoption of the Microsoft Kinect (first generation) in medical scenarios should therefore be considered with respect to the application it serves having clear in mind its performances and limitations.