We must stop to rest for a while and do some exercise to restore the knee joint, because if the knee joint is really damaged, it is irreversible. The most easily worn parts in fitness training are the knee joint and shoulder joint, which are the hardest hit areas in fitness training, especially the knee joint, which is the most seriously injured part in fitness, running, mountaineering and other sports. Many friends who love running, fitness, mountaineering, cycling and other sports have to give up their love because they don't protect their knees in sports.