If the foot is not correct, the body's protection mechanism will prompt the body's joints to compensate instead, the ankle, knee, hip, pelvis, and spine, from the bottom to the top, are involved in compensation.
The joints of the human body are interlocked, and if there is a problem with the foot, the body will be crooked, just like the unstable "foundation" of a building, which causes the building to collapse.
Abnormalities in the foot are an important cause of compensatory limb and thus abnormal gait.