The correlation between rear foot angle and the force applied to the knee extensor mechanism in subjects with subtalar hyper pronation

Abstract

Research question: Is there any correlation between the rear foot angle and the force applied to the knee extensor mechanism in subjects with subtalar hyper pronation? Introduction: Foot hyper pronation can induce lower extremity malalignment, frequently leading to structural and functional deficits both in standing and walking [1]. It has been proposed that excessive hyper pronation can delay the external rotation of the tibia and alter the desirable timing between knee extension and rear foot supination, leading to increase strain on soft tissues around the knee joint like the extensor mechanism [2]. The aim of this study was to investigate whether a correlation exists between the rear foot angle and the force applied to the knee extensormechanism in subjects with subtalar hyper pronation. Materials andmethods: 15 female subjects (aged 19–25 years) with subtalar hyper pronation (rear foot angle more than 4◦) were studied in this investigation. Kinetic and kinematic data were collected by employing a force platform (Kistler®, Switzerland) and six camera motion capture system (Qualisys®, Ltd., Sweden) while walking at their preferred speed. The mean knee extensor mechanism forces were quantified using Newtonian inverse dynamics during stance phase of walking and then, the correlation between mean knee extensor mechanism forces and the rear foot angle (based on the resting calcaneal stance position) were examined using the Pearson correlation. Results: The statistical analysis revealed a high positive correlation between the rear foot angle and the extensormechanism force (r=0.828, P<0.001). Discussion: It can be stated that the larger rear foot angle will be accompanied with the larger knee extensor mechanism force through which developing a tendency towards musculoskeletal injuries.