Due to the rapid development of sports and people’s love for sports, athletes often perform resistance training beyond the body to achieve better results, resulting in frequent muscle injuries. After the injury, the athlete cannot return to the state before the injury in time, which destroys the previous training results and hinders the athlete from improving to the professional level. Therefore, the research of athletes’ post-injury rehabilitation is the central subject of modern sports science research. This paper used OpenSim technology to study the rehabilitation management of sports athletes’ muscle injury. In this paper, the OpenSim skeletal muscle model was first established, followed by muscle modeling and characteristic analysis, and then a muscle rehabilitation system was constructed. The experimental part used the limb rehabilitation device model of this paper to carry out muscle rehabilitation training for patients with muscle injury, and compared it with conventional rehabilitation training. The experimental results showed that the limb rehabilitation device in this paper had a better rehabilitation effect. Compared with the traditional rehabilitation training, the excellent rate of the total active range of motion of the joints and the satisfaction of rehabilitation nursing were both increased by 10%.