Knee pain after running is mostly seen in some people who have too much exercise, or who usually have less exercise and suddenly do exercise. The cause of this situation is mostly due to joint injuries caused by sports, such as synovitis of the knee joint, or ligament injuries around the knee joint. When knee pain after running occurs, it is recommended to stop continuing the exercise and rest more. If the pain persists for 2-3 days, the injury may be more serious, and you should go to the hospital in time for an x-ray, or an MRI of the knee to determine whether there is any damage to the bones, muscles, fascia and surrounding tissues. If there is a fracture or ligament rupture, it is necessary to take braking or other treatment methods, or even surgery. Some injuries to the knee joint can greatly affect weight-bearing, walking, running, jumping and other sports. Therefore, it is important to treat the injury in a timely manner and to protect the knee joint.