Medially posted insoles consistently influence foot pronation in runners with and without anterior knee pain Pedro Rodrigues a,b, *, Ryan Chang b,c , Trampas TenBroek a,b , Joseph Hamill b a New Balance Sports Research Laboratory, Lawrence, MA, United States b Biomechanics Laboratory, University of Massachusetts, Amherst, MA, United States c Kintec Inc., Surrey, BC, Canada 1. Introduction Anterior knee pain (AKP) is one of the most common injuries among runners [1]. One biomechanical risk factor thought to predispose a runner to this injury is ‘‘excessive’’ pronation [2–5]. Consequently, devices designed with the intent to control pronation (motion controlling devices (MCD)), such as medially posted insoles and orthotics are often recommended by clinicians to treat AKP. These recommendations have been supported by clinical research, which have shown these devices to effectively reduce pain and improve function [4,6–9]. Biomechanical studies, however, have not found these MCD to consistently influence the kinematics of the ankle joint complex (AJC, talocrural and subtalar joints), the tibia, and/or the knee when running. Furthermore, one could theoretically expect that studies which have found reductions in foot pronation would have concurrently found reductions in tibial rotation because of their proposed coupling [10]. While some authors have captured these changes occurring concurrently [11], others have not. MacLean, Davis and Hamill [12] and Eng and Pierrynowski [13] both found MCD to reduce peak AJC eversion in runners but did not find them to influence the transverse plane kinematics of the tibia or knee. In contrast, others have found that MCD limit tibial internal rotation, but do not influence the mechanics of the AJC [14–16]. While MCD have been shown to be clinically effective, the inconsistent biomechanical results have called into question the underlying mechanisms that bring about these clinical benefits. The discrepancies seen between these biomechanical and clinical studies may be due to methodological issues associated with defining the segmental coordinate systems (SCS). Clinically, it is important to quantify the position of the calcaneus as it relates to foot type and injury [17], however this position is often not captured in biomechanical studies. One way of defining the Gait & Posture 37 (2013) 526–531 A R T I C L E I N F O Article history: Received 6 February 2012 Received in revised form 4 September 2012 Accepted 13 September 2012 Keywords: Running Orthotics Patellofemoral syndrome A B S T R A C T Anterior knee pain (AKP) is a common injury among runners and effectively treated with posted insoles and foot orthotics. While clinically effective, the underlying biomechanical mechanisms that bring about these improvements remain debatable. Several methodological factors contribute to the inconsistent biomechanical findings, including errors associated with removing and reattaching markers, inferring foot motion from markers placed externally on a shoe, and redefining segmental coordinate systems between conditions. Therefore, the purpose of this study was to evaluate the influence of medially posted insoles on lower extremity kinematics in runners with and without AKP while trying to limit the influence of these methodological factors. Kinematics of 16 asymptomatic and 17 runners with AKP were collected while running with and without insoles. Reflective markers were attached to the surface of the calcaneus and kept in place (as opposed to detached) between conditions, eliminating the error associated with reattaching markers and redefining segmental coordinate systems. Using these methods, no significant interactions between insole and injury and the main effect of injury were detected (p > 0.05); therefore, means were pooled across injury. Insoles, on average, reduced peak eversion by 3.68 (95% confidence interval À2.98 to À4.38), peak eversion velocity by 53.28/s (95% confidence interval À32.9 to À73.4) and eversion range of motion by 1.33 (95% confidence interval À0.8 to À1.9). However, while insoles systematically reduced eversion variables, they had small influences on the transverse plane kinematics of the tibia or knee, indicating that they may bring about their clinical effect by influencing other variables. ß 2012 Elsevier B.V. All rights reserved. * Corresponding author at: New Balance Athletic Shoe, Inc., Lawrence, MA, United States. Tel.: +1 978 725 2854. E-mail addresses: pedro.rodrigues@newbalance.com, pedro.rodrigues.a@gmail.com (P. Rodrigues). Contents lists available at SciVerse ScienceDirect Gait & Posture jo u rn al h om ep age: ww w.els evier.c o m/lo c ate/g aitp os t 0966-6362/$ – see front matter ß 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.gaitpost.2012.09.027