Aging of the knee joint starts at the age of thirty. If you have soreness on the inside of your knee after exercise, it means that your knee has started to deteriorate. Therefore, from the age of thirty, we should focus on “saving” the knee joint. The specific knee protection method: 1, warm up before exercise, so that the knee joint to adapt to the 2, the original exercise is not a large amount of people, can choose to swim, the buoyancy of the water can reduce joint wear.