Alterations in Balance Strategies Due to Joint Bracing in Static Postural Standing

Abstract

Introduction: Employment of braces can increase the standing stability by external support of the joints. Examining the effects of different braces, specifically in numerous static postures is practically difficult; therefore, the current parametric study aimed at modeling the alterations of the muscular recruitment patterns during static postures caused by wearing different braces. Materials and Methods: A biomechanical model of the musculoskeletal system was employed to simulate over 27,000 standing postures with different joint angles and brace conditions. Activation of the muscles in standing posture was calculated using optimized inverse dynamics. The postures with muscle efforts beyond the physiological limit were considered as the feasible postures. Results: Braces increased the number of feasible postures. However, their effects depended on the joint angles. Knee flexion assisted in providing balance for more postures. The maximum number of feasible postures occurred in midrange knee flexion (30 degrees). High and low stiffness braces caused relatively similar outcomes. Wearing the upper joint braces (knee or hip) relieved the ankle joint muscles and prominently recruited the knee muscles to maintain the balance. Results also suggested that if an individual, in practice, intended to wear only one brace to have the most efficient support in balance, the ankle brace was the best choice. Conclusion: Braces can assist in providing balance for the quiet standing condition. It is better to let knee joint rotate and support the ankle by braces.