Biomechanics gait is the study of the mechanical principles that govern human walking and running, focusing on how forces, movements, and energy transfers interact within the musculoskeletal system to produce locomotion. This field combines concepts from physics, engineering, and anatomy to analyze the kinematics (motion) and kinetics (forces) of the gait cycle, providing insights into how bones, joints, muscles, and tendons work together to create efficient movement. Key areas of interest in biomechanics gait include the analysis of joint angles, ground reaction forces, muscle activation patterns, and energy conservation during each phase of the gait cycle—from heel strike to toe-off. For example, during heel strike, the ankle dorsiflexes to absorb impact, while the knee flexes to cushion the body’s weight, demonstrating how different joints coordinate to manage forces. Kinetically, biomechanics gait examines the vertical, horizontal, and mediolateral forces exerted on the ground, which influence propulsion and stability. Ground reaction forces, measured using force plates, reveal how the body interacts with the environment, with peaks during heel strike and toe-off indicating impact absorption and propulsion, respectively. Muscle activation patterns, tracked via electromyography, show how muscles like the gastrocnemius and tibialis anterior contract to control foot movement and maintain balance. Biomechanics gait also explores how deviations from normal patterns—such as overpronation, limping, or shortened stride length—can lead to inefficiencies, pain, or injury. For instance, excessive pronation during midstance may increase stress on the plantar fascia, contributing to plantar fasciitis, while asymmetrical gait can strain the lower back or hips. Understanding these mechanical relationships is critical for developing interventions like orthotics, physical therapy exercises, or footwear modifications that correct abnormal gait patterns and improve function. In research and clinical practice, biomechanics gait provides a scientific basis for evaluating the effectiveness of treatments, designing assistive devices, and optimizing athletic performance, making it an essential discipline in healthcare, sports science, and rehabilitation.