Walking 20,000 steps a day can really damage the knee, it takes quite a long time to walk 20,000 steps a day, and the pressure on the joints during the walking process is very high. The continuous pressure on the joints causes relatively heavy damage to the cartilage and soft tissues of the joints. As the joint is always under downward pressure during walking, the articular cartilage is subjected to greater forces of wear and tear, and over time this can lead to damage to the knee joint that is difficult to recover from. Because the articular cartilage of the knee joint is non-renewable, there is no way to grow it again once it wears out, so try to control the number of steps you take each day, not too many.