There is a noise in the knee joint when pedaling. How's it going?

There are three reasons for leg joint hiccups: 1) gas escaping, 2) joint displacement and 3) femoral joint interface caused by arthritis. 1) Gas escape: Scientists believe that there is a liquid called synovial fluid between our joints to lubricate them. This synovial fluid contains some gases, such as oxygen, nitrogen and carbon dioxide. These gases form bubbles in the synovial fluid. When we stretch our joints, the gas in the synovial fluid will be quickly lost, because the bubbles burst and cause hiccups. You sometimes hear burps. This situation is mostly knee joint and ankle joint. 3) Joint thick interface caused by arthritis: Arthritis will destroy cartilage tissue between joints, resulting in the joint interface is no longer smooth. In this case, joint friction will produce noise. Is the sound produced by moving joints harmful to the body? Not necessarily. If the movable joint burps and feels pain, you should see a doctor. Some people like to move their knuckles to make a sound. Some research reports point out that this habit will destroy the soft tissue between the knuckles and weaken the grip strength of our fingers. Novices often have this phenomenon, and it should be said that most of them are normal. People's joints, some parts and some angles are less active on weekdays, just like a new car, it takes a running-in period to move smoothly. Shoulder joint, in particular, is not very active at ordinary times, but in Tai Ji Chuan, all joints often do circular motion and lifting motion, which will make the "dead" joints lively, so it is inevitable to make a noise at first. However, it should be noted that beginners must pay attention to the relaxation of joints, let nature take its course, do not do strenuous exercise, and the joints can rotate as much as possible. Don't try to be brave, don't have the idea that you are not afraid of suffering and pain. Pay attention to protect joints from injury. Once the joint is damaged, it is often irreversible, which is a lifetime thing. As long as you persist, the joints will naturally open over time. Don't act in a hurry. After practicing for a month or two, if you keep practicing every day and it still rings, there may be a problem. You need to stop practicing for a while until you check. It's not the sound of bones, it's the sound of ligament sliding, and the reason for ligament loosening. Don't let it ring on purpose, it will get better gradually. There are many factors that cause joint noise, one of which is related to too little joint movement. Too little exercise reduces the working ability of muscles, ligaments and synovial tissues around joints, followed by osteoarthropathy, such as cervical spondylosis, low back pain and scapulohumeral periarthritis. Exercise can choose to perform the correct joint movement.