TPE belongs to the category of plastics referred to as ethylene propylene thermoplastic vulcanite's, and therefore, has performance characteristics which are similar to that of vulcanized rubber. The selection of thermoplastic elastomer (TPE) as a preferred plastic material for orthotic application was based upon several of its unique performance characteristics. The performance characteristics of TPE - its semi-rigidity, flexibility and durability - were felt to be of biomechanical advantage when applied to the function of the AFO and the biomechanical foot orthosis. The TPE AFO provides a smoother and more normal gait cycle from heel-strike through terminal stance, increased capacity to control the ankle in the coronal plane, and a rigid plantar flexion position during swing phase. All of the above contribute to the enhancement of the three components of walking: progression, standing stability and energy conservation. In addition, TPE provides greater control of the ankle in the coronal plane because of its capacity to hug and conform more comfortably to the anatomy of the leg. Patients experience greater ease when ascending and descending stairs as well as a greater ease when bending at the ankles.