Foot Orthotics are constructed
from various materials consisting of plastics, foam, rubbers, and cork
composites that are utilized for their mechanical properties.
The main similarity of all Foot Orthotics is the principle of their
structure. The core is comprised of a plastic material more commonly
referred to as the shell. External support structures on the underside
of the shell material are utilized for balance and support inside the
footwear; these are commonly referred to as extrinsic posts. Soft
padding is placed on the underside and the topside to absorb compression
forces when walking and running, this includes the top covers, underlay
materials and arch fills.
All of these materials have the goal of
improving foot function and minimizing the stress forces that cause foot
deformity and pain.
Dependent on the reason for the prescription of Foot Orthotics, all
of the above mentioned materials can be utilized in many combinations to
achieve three broad categories of Foot Orthotics:
- Those that primarily attempt to change foot function, known as functional Foot Orthotics
- Those that are mainly protective or accommodative in nature, and
- Those that combine functional control with accommodation for comfort.