If you are aware of your foot type, and you relate to some of the conditions above, then you need to find what shoe is your type.
If you over pronate you need to be fitted with a shoe that provides stability and motion control. A light fitting, too flexible shoe will not provide enough support for pronators.
People who over supinate require extra cushioning in their shoes.
Shoes come in different shapes..they are either constructed on a curved-last or a straight-last. When you look at the sole of running shoes in the shop you will notice that some soles have a curved appearance and if are not symmetrical in shape, whereas other shoes are quite straight with the right half nearly the same size and shape as the left. Over Supinators tend to fare better with a curved-last, as it tends to curve to fit the foot better.
Running shoes also differ in their construction...if you pull out the inner padding of the shoe and examine the interior you will discover that the shoe has either a slip-last or a board-last. The slip lasted shoe has it's fabric sewn together, whereas the board-lasted shoe bottom is often covered in cardboard. Other shoes are a combination of both. Whats the deal? you ask..well, slip lasted shoes are often more flexible and remember, it's the flexible fit that suits the over supinators. The board-last is firmer and offers more support for the over pronator. If you have a nuetral strike then you might prefer the combination.
Now to the part of the shoe that requires all that expensive technology, the midsole..the midsole is the base of the shoe, it's the part that provides the shock absorption and many shoes have a variety of materials inserted in them to provide cushioning. If the midsole is made up of a heavy material it will be stable in it's support, but will have less cushioning and flexibility. A pronator requires the stability but they also need cushioning as well, therefore a dual density shoe is the best choice...to pick a dual density shoe..look at the soles, they are made up of two different colours, with the darker colour being the tougher material providing the most support. Supinators on the other hand are usually fitted with single density midsole as they provide good cushioning and offer a little more flexibility.
Most running shoes are now graded as to their degree of cushioning, flexibility and responsiveness. Cushioning determines how soft or firm the midsole and heel are; flexibility relates to the amount of energy required to flex the toe, you can often test the flexibilty of the shoes by holding, bending and twisting them in your hands; and responsiveness refers to how efficient the shoes feel and move on your feet when you are running.