Material Properties: The rigidity with which the orthoses are constructed has an impact on their efficiency. There is considerable evidence that increasing plantar fascia stiffness reduces the overall amount of stress, but it also causes more discomfort. Used material should also offer an appropriate combination of elasticity (for support and comfort) and damping (for impact loads during walking). The common materials are EVA (ethylene- vinyl acetate), thermoplastic urethane and foam composite.
Load Distribution: Knowledge regarding the distribution of loads on the foot throughout the gait cycle is especially critical in orthosis design.

• Ground Reaction Forces (GRF): The kinematics between the foot and ground yields from the ground reaction forces which in turn affect foot mechanics. An effective orthosis not only must give support to these forces but also cannot inhibit natural movements to a significant extent.
• Plantar Pressure Distribution: It may be possible to incorporate the application of additional pressure to certain locations in the foot in combination with monitoring of the distribution of pressure across the plantar surface of the foot for making adjustments in orthotic design. Even distribution of pressure also frees areas of concentrated pressure making it less painful and more functional.

Arch Support: An orthosis must offer good arch support. It is found that a higher arch support can lower peak plantar pressure and strain for the plantar fascia. Research also shows that the stability of foot pain and gait can be improved with an increase of arch support by as much as 45.7% and medial inclination by as much as 25.5%.
Foot Positioning: Orthotic joint surfaces need to be correctly aligned with anatomic joint surfaces in relationship to the coronal plane. Misalignment can also cause shear, which can work against the body’s normal movements, and therefore can actually worsen the condition. An orthosis should limit the foot position to be in a more neutral stance whilst at the same time permitting movements as required.
Medial Posting Inclination: Changing the medial posting can assist in trying to get the return excessive rearfoot eversion that is evidently present in a flat footed individual. This adjustment is very important for creating a better alignment when standing, taking a walk or even jogging.
Customization: Each orthosis might be designed individually with regard to the shape of the foot and its functional load. As a result, particular patterns that have been acquired through 3D scanning can be more fitting and comfortable when encapsulated in custom molds.
Thermal Regulation: The foot gets swollen as a result of shoe pressure, frictions and repeated motions. The used materials in the orthosis should be selected such that it may ventilate the skin and also wick sweat in order to avoid discomfort due to heat.
Surface Contact: The material surface in contact with the foot must have low friction to prevent blisters and other skin issues but also sufficient grip to avoid slippage inside the shoe.