Neutral foot
A neutral foot is the more desirable foot structure – this foot type rolls inward, but adjusts to provide support as the person pushes off with the forefoot and toes. This foot therefore provides both stability and shock absorption as required.
Flat foot (pronation)
The flat foot rolls inward, and flattens when bearing weigh which places stress on the inner foot structures. This type of foot is very- flexible which limits stability while walking.
A person with a flat foot tends to wear out the inner side of their shoes and calluses can be seen under the base of the second and third toes and on the inside of the big toe. If the shoe is placed on a flat surface it will tilt inward.
Problems related to flat feet include: hip pain, stress fractures of the foot and ankle (metatarsal stress fractures), plantar fasciitis (heel pain and spurs), Achilles tendonitis, and patellar (knee) pain.
High arched foot (supinator
A high arched foot rolls outward. It is more rigid and weight is borne on the outer part of the foot. This type of foot has less shock absorption which causes forces to be transmitted up to the leg.
A person with a high arched foot tends to wear their shoes out on the outer side from the heel to the toe. Calluses can be found along the outer edge of the foot and especially under, or next to, the fifth toe. The shoe will tilt outward when placed on a flat surface.
Problems caused by a high arch can include: stress fractures in the tibia (shinbone) or femur (thighbone), as well as Achilles tendonitis and plantar fasciitis (heel pain and spurs).
It is important to wear footwear that corresponds with your type of foot.
A neutral foot needs a stable shoe that provides both cushioning and pronation control. A high-arched foot needs a very cushioned shoe that will provide shock absorption and reduce the impact send up to the legs. A flat foot needs a shoe with motion control – a shoe that is not very flexible is best.
Sometimes however, proper footwear is not enough to fully support the foot and prevent injury, and this is where orthosis are needed. Orthosis replace the insole in your shoe. There are two basic types of orthotic insoles; one can be bought as a range of over the counter inserts that provide extra cushioning, the other is a custom made insole that is molded off the patient’s foot. Custom orthotics are more comfortable as they are suited to your foot, and give maximum support where needed. Custom orthosis are a good option to ensure that you do not suffer from injuries or require operations in later years and most medical aid schemes do pay for orthotics.
Source: http://www.mckinley.illinois.edu/handouts/foot_types/foot_types.htm