Virtual reality (VR) environments present nowadays a powerful tool for visual feedback in assessment and training programs of rehabilitation. Designing appropriate target-oriented tasks may enhance therehabilitation options available in biomechanical dynamometry. The subjects are motivated to achieve a goal in the VR environment, and therefore, their performance often increases. This adds a significant value to the evaluation of the subject’s capabilities and design of the appropriate training program that may enhance the selective joint torque control in children with cerebral palsy. In this paper, we suggest a VR environment that offers motivation for maximal joint torque generation and VE for joint torque control training. A dynamometer with torque sensor and axis motor was used in the process and enabled biomechanical information, i.e. knee joint torque and surface electromyography, assessment during the target-oriented VR based task. A 12-year old child with cerebral palsy participated in the case study. The protocol consisted of three consecutive days of virtual reality-supported training under various conditions, like task velocity and difficulty level. Our data suggested that there were improvements in the knee joint torque tracking and increased target hit score regardless of the task difficulty level. Besides the improvement of the knee joint torque control, presumably more muscle power could be generated, resulting in more successful performance at targets where high joint torque was required. Apparently high level of motivation has been noticed. The advantages of using VE forrehabilitation services were shown in variability of attractive target oriented tasks, repeatability and highly motivated subjects. Hereby, a VR environment guided dynamometer based assessment and training for single joint was demonstrated. The promising outcomes call for longer training period and clinical evaluation of modern therapeutic approach.