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.