The feeling of a tendon in the knee is not smooth over, indicating that the knee joint activity is limited, which may be caused by physiological factors such as prolonged standing and sedentary activities, or may be caused by pathologic factors such as trauma or osteoarthritis. 1. Physiological factors: due to maintaining a position for a long time, such as sedentary, standing for a long time, etc., can lead to stiffness and spasm of the soft tissues around the knee joint. When you move suddenly, you may have the feeling of limitation in joint movement, which can be gradually relieved after slowly changing the posture and moving the limbs. 2. Trauma: Trauma to the knee joint can lead to meniscus injury, ligament injury and other surrounding soft tissue injuries, which can lead to instability of the knee joint, or produce free bodies in the joint, which can lead to limitation of the knee joint, and can be accompanied by pain and swelling of the knee joint. 3. Osteoarthritis: Degenerative lesions of the knee joint can lead to osteoarthritis, with osteophytes, cartilage wear and other lesions, which can cause joint pain and limited movement during activities. The knee feels like there is a tendon not smooth over, if not relieved for a long time, it is recommended that the patient timely hospital consultation, identify the causes and then give standardized treatment, usually in the exercise before the warm-up activities should be done.