Summary

This article and podcast explores the history and rationale behind the use of a 4-degree rearfoot post in orthotic devices, specifically as developed by Dr. Merton Root in the 1950s and 1960s. The author, Ray Anthony, explains that Root's design was based on the idea that the average foot requires 4 degrees of heel eversion during the contact phase of gait, a belief that influenced the development of the Root Functional Foot Orthosis (RFFO). Anthony critiques the modern use of this prescription protocol, arguing that the 4-degree rearfoot post is only effective within the context of the rigid materials and design principles of the RFFO, and that its efficacy in modern orthotic designs utilizing flexible materials is questionable. He emphasizes that Root’s prescription paradigm is not a universal solution for orthotic design and that contemporary understanding of foot biomechanics has evolved significantly since Root’s original work.