The development of musculoskeletal rehabilitation systems is a complex scientific and technical challenge. The integration of modules for analyzing human condition based on data from medical equipment further complicates this task. To simplify the development process of such systems, a general structural framework has been implemented, incorporating key components of a musculoskeletal rehabilitation system (MRS) utilizing biofeedback (BFB) and virtual reality (VR) technologies. Based on this framework, a mathematical model of the MRS with BFB has been developed. The model formalizes the processes of collecting, processing, and analyzing biological signals and motion data, as well as their use for controlling the virtual environment and hardware components of the system. Key stages of the system's operation are considered, including data acquisition, noise filtering, feedback signal generation, and their application to modify the parameters of the virtual environment and hardware. The mathematical framework also includes filtering methods, data mining techniques, and hardware control algorithms. The proposed model will facilitate the implementation of software components, integration of hardware modules, and organization of interactions within the MRS.