The way in which the feet function or works can have a significant effect on the rest of the body. The feet are generally thought to be the foundation of the body and just like the tall building analogy, if that foundation isn't correct, then something can go wrong higher up. There are many different kinds of dysfunctional conditions that will affect that foundation and how the foot interacts with the surface. That interaction will have numerous impacts higher up the body.
One of the issues that may go wrong is something that is generally given the name “overpronation”. This term can often be used and misused, so probably should be avoided. The word relates to the foot rolling inwards at the ankle joint as well as the arch of the foot collapsing. This is really quite a normal motion and is only a issue if there to an excessive amount of it. Why the word is such an issue is that there is no agreement as to what is too much and what is normal. This leads to plenty of indecision in research as well as in clinical practice, particularly when choices have to be made if the overpronation ought to be addressed or not.
The impact that this issue may have on the body are alleged to range from bunions and plantar fasciitis in the feet to lower leg and knee problems in runners. There are many ways to treat it, again with a lot of disagreement between health professionals as to the best way to treat it. Logically the treatment of the overpronation should be directed at the cause and there is no such thing as a one size fits all. If the problem is caused by tight calf muscles, then stretches of those tight muscles would be the logical therapy. If the problem is the control of muscles at the hip, then the therapy should be aimed at that. If the problem is because of weak foot muscles, then that is the best place to start the rehabilitation with exercises. When the concern is due to a bony alignment issue in the foot, then foot orthotics will often be prescribed.