You will also hear the term 'pronation' in some sports shops. The idea was born somewhere in the early 90s from the observation that some people walk on the inside of their feet, some on the middle and some on the outside. OK, and some have their toes pointed outwards while others point them inwards, and some have high arches and some have low arches. Some bright spark got the idea that anyone deviating from the middle of the range was aberrant, and should be corrected. That is, if you tend to walk on the inside of your foot with your toes pointed outwards, you should be forced to change this so you walk on the middle of your foot, and so on.

Now, a reasonable person would have thought that you would tend to walk in a manner that was most comfortable, for you and your bones and tendons. But no, if you deviate from the average you must be corrected, and forced to change your deviant ways. What effect this would have on the bones and tendons of your feet was not considered. Fortunately the stupidity of this idea was recognised by the end of the 90s, and competent medical practitioners and sports doctors do not subscribe to this idea. Actually, those who do know sports physiology condemn the idea totally. Unfortunately, a lot of the marketing and shop assistant guys have yet to be told that this idea is dead. It gives them some authority you see, and they have proved to be very reluctant to yield that aura (or the cash flow from promoting the idea).

Before leaving this subject, I should add that for a very small fraction of the population there is some benefit to be had from custom orthodics, but these must be prescribed by a competent podiatrist. I have noarguement with those. Mass-marketed special foot beds are not medical devices, and are usually either irrelevant, useless, or even in some cases dangerous. If it feels wrong, it probably is! Listen to your feet, not to the guy trying to sell you something. Mind you, some of the replacement footbeds are little more than a flat bit of foam with a slight heel-cup. I doubt they do much harm, and in some cases may be used to adjust the size of the shoe.

So let us now see what other have said on this subject.