If knee pain occurs after running alone, the pain can generally be relieved significantly after about 2-3 days of rest. However, if the knee joint is already diseased before running, the recovery time may take more than two weeks, depending on the individual. Knee pain is more common after running, usually due to other symptoms in the knee joint or chronic diseases, such as chronic meniscal injury, cruciate ligament strain or osteoarthritis. When knee pain occurs after running, you should first reduce the activity of the knee joint, wear a knee brace for protection, and apply heat to the knee locally, or use physical therapy such as acupuncture and moxibustion. If the pain is severe, you can take non-steroidal anti-inflammatory and analgesic drugs orally under the guidance of a doctor to relieve the symptoms, and you can also use drugs to promote cartilage repair, such as glucosamine hydrochloride tablets. If the patient’s pain is not relieved after 3-7 days, it is recommended to go to the hospital for examination and treatment, usually an MRI of the knee is required to clarify the diagnosis.