Analysis of the gait cycle with an inverted pendulum model

Walking is one of the fundamental motor behaviors of human life and constitutes a significant part of daily activities. Understanding the underlying biomechanical principles of walking is crucial for assessing both normal and pathological gait. In this context, modeling biomechanical parameters such as joint kinematics, muscle forces, and ground reaction forces provides valuable insights for clinical evaluations, robotic system design, and the analysis of amputation conditions. Due to the complex structure of human gait, various simplification approaches are required for its mathematical modeling. In this study, pendulum-based models commonly used in gait analysis were comprehensively examined. In particular, the linear inverted pendulum model and the spring-loaded inverted pendulum model were analyzed in detail, and their ability to represent both normal and post-amputation walking was evaluated in light of experimental data from the literature. The analyses revealed that inverted pendulum-based models are computationally efficient, parametrically simple, and adaptable to different walking conditions. Comparative evaluations indicated that the inverted pendulum model can accurately represent lower-limb kinematics and post-amputation gait dynamics. The results demonstrate that inverted pendulum-based models are powerful and practical tools for analyzing both normal and post-amputation walking.