The change in the basic support plane from the horizontal plane is the active part of any arch support / orthotic. Other researchers have hypothesized a functional relationship between the critical or specific angular embodiment’s of their intellectual property and any treatment benefits observed.
Unfortunately the curvature of the human foot forms a hyperbolic curve at it’s maximum value, near the apex of the arch, where the angle is generally observed in the frontal plane. Unless three points could be defined and shown to relate directly with clinical function, any measured angle, pitch, or slope of the device was not functionally relevant.
When the specific three points in the frontal plane section were Identified a direct relationship between measurement of this angle and empirical benefits of the treatment were recorded. This same measurement technique has been tested in thousands of cases over a 30 year period. Many important things related to a treatment that progressively changes the angle of support.
One of the most important things I learned from 30 years of empirical studies was that every 5 degree increase in this angle produced an increase in the forces applied to the arch, and a noticeable change in treatment benefits. It was obvious clinically that a treatment program that progressively increased the angle at 5 degree increments over time, generated a far greater success rate than if the treatment continued with the starting angle of correction.
It soon became obvious that we are way under treating with orthotics in general, that resolution of many medical conditions caused by gait required between 25-35 degrees of correction. These same measurement techniques applied to hundreds of custom and OTC orthotics on the market reveal angular correction no higher than 20 degrees.