First, the problem of knee bending is more likely to occur when squatting, cycling or running, bending or stretching your legs. However, the knee joint internal buckle will easily cause joint wear and ligament sprain due to improper joint position. Because the knee joint has a fixed direction, it makes the bending of the thigh straight and has a fixed direction. This is just like two gears under normal rotation, there will be no serious wear, and if the gears are stuck in a deviated direction, they will be more prone to wear.
Second, knee joint extrusion
The problem of knee joint extrusion is easy to happen when bodybuilders do squat or leg lifting training, because the leg muscles are too tight, which leads to knee joint locking and knee joint extrusion. When the knee joint is locked, you can't share your weight with your muscles. You can only rely on the joints to bear the weight, making the knee joint a stressed part. However, the knee joint injury caused by knee extrusion will change the leg shape, make the leg more and more crooked, unable to straighten, and even break the knee joint in severe cases.
Third, use joints to play a buffering role.
When an athlete is doing strenuous exercise such as squatting, running, skipping rope, etc., it is easy to make the whole jumped leg fall to the ground directly without bending, which will make the joints of the knee joint directly bear the inertial gravity of the vertical falling body, so it is easy to damage the knee joint only by relying on the joint for buffering, which will easily lead to the degradation of the bearing capacity of the knee joint. The correct way is to use muscles to bend your legs or stand on tiptoe when jumping to avoid knee injury.
In fact, before exercise, athletes have the common sense of correct exercise, consciously eliminate the wrong way of exercise and avoid joint injury, then they can gain the benefits brought by squat, running and any lower limb exercise.