Biomechanical analysis of the role of shoe inserts for over pronated foot during running

13 Introduction 1.1 Pronation Subtalar joint pronation is a motion which combines dorsiflexion, abduction, and eversion of the foot which respect to the leg, providing the primary mechanism by which transverse rotations occur between the leg and foot [1]. Excessive and an increased velocity of pronation during stance, have been related with overuse injuries in running, although the mechanisms behind this relationship are still unclear [2] [3] [4]. Figura 1.1 Pronated foot Vs Normal foot (adapted from Philadelphia Runner website: http://www.philadelphiarunner.com) 1.2 Overuse Injuries Overuse injuries are those injuries that result from repetitive subtraumatic forces that overuse and stress the muscuskeletical tissues [5]. Willems et al. 2006 have identified the central heel strike, the excessive eversion and the increased lateral roll off of the ankle as risk factors for exercise related lower leg pain. Exercise related leg pain includes, shin splints, shin pain, medial tibial stress pain, periostitis, compartment syndrome and stress fractures [2]. On a second study, Willlems found that the risk factors running with shoes are the increased pronation excursion and accelerated reinversion[3]. These studies were carried on by comparing an injury group of subjects that developed exercise related lower leg pain with a group of subjects who had never Chapter1