The deterioration of the components of the rotator cuff is one of the most frequent causes of musculoskeletal pain and disability in the world. The conditions of the rotator cuff increase with the passage of time, since they have a direct relationship with a process of deterioration rather than with a traumatic event. In order to decrease pain and recover shoulder movement, patients are usually treated by regular sessions with a physiotherapist. However, more sessions are required than those stipulated to fully obtain recover mobility. This paper present the development of portable prototype to rehabilitate acute rotator cuff injure, designed from biomechanical analysis and ranges the kinematics and dynamics articulated in the present design determine important requirements in obtaining greater functionality of the prototype and with it, allows the identification of sensors and actuators for executing two types of specific movements: flexion / extension and external / internal rotation by means of a soft rehabilitation robot.