Foot Orthosis in Running

Foot orthosis is a popular strategy for runners aiming to reduce the injury risk and improve performance in running. Companies of foot orthosis claim for a high number of benefits, however, the literature is controversy in many aspects and there are not systematic results because of the use of them. The aim of this chapter is, firstly, to introduce the reader about the concept of foot orthosis and its different definitions and types. Secondly, to show the most important scientific literature about its biomechanical and physiological effects during running. These biomechanical and physiological effects were divided into the following sections in order to be clear for the reader: kinematics, impact transmission, plantar pressure, neuromuscular activation, comfort perception, and thermal assessment. Finally, some indications of future research were provided.