How to choose running shoe you need

　　The first step is deciding the type of foot you have - it is probably the most important aspect of matching a brand and model of running shoe to the individual. During normal running (and walking), the outside of the heel strikes the ground first (supinated position) - this is why the wear is common in this area. The foot then rolls inward and flattens out along the longitudinal arch-pronation (pronation). The foot should then supinate by rolling through the ball - this helps make the foot a rigid lever for efficient propulsion. A number of different biomechanical problems can interfere with these normal motions. A running shoe can help facilitate this normal function and help overcome many of the minor biomechanical problems that interfere with a motion. An inappropriate running shoe can actually have the effect of interfering with this normal function.
Usually, most runners who develop an injury either supinate (roll out) or pronate (roll in) too much. Normal amounts of pronation and supination are needed for normal function, but abnormal amounts increase the risk for injury.
Excessive pronation is the most common cause of running injury. A pronated foot rolls inwards at the ankle, the midfoot bulges inwards and the longitudinal arch flattens. Those who over-pronate generally have very flexible and unstable feet, so need running shoes with a lot of motion control. A motion control shoe has design features that give a high level of support - a firmer anti-pronation post on the inside of the midsole; a firm or dual density midsole; and a a firm heel counter.
A supinated foot rolls outwards at the ankle and has a high arch. They tend to be more rigid and are very poor at absorbing shock, so they will need running shoes with a lot of cushioning. Cushioned shoes tend to be poor at motion control.
The amount of excessive pronation or supination present will determine if you need a neutral running shoe with an even amount of mild motion control and mild shock absorption; or a running shoe designed for mild, moderate or severe amount of pronation, with mild, moderate, or severe motion control or stability; or a running shoe for mild, moderate or severe amount of supination, with varying degrees of shock absorption or cushioning.