To move against the wall, you need to bend your knees 90? And last for a while. At this time, although your torso is supported by the wall, it also puts an excessive burden on your knee joint. The composition of knee joint is diverse, including anterior and posterior cruciate ligament, medial and lateral collateral ligament patellar ligament, and more importantly meniscus. When there is continuous pressure, the ligament is in a state of overload and strain, which is easy to strain. At that time, the symptoms may disappear after some activities. However, if you exercise regularly, chronic inflammatory strain will gradually accumulate and form, leading to knee joint injury. Some of them are more troublesome to recover and the injury is easy, but it is not as simple as we thought, so exercise should be moderate, and some exercises harmful to joints and muscles should be done less.