The aim of the gait is to transport the body in different directions with desired speed. During this action; joints, muscles, tendons and ligaments are used in related extremities. Center of gravity of the body moves up-down in vertical and both sides in horizontal planes. Combination of these movements form `eight figure`. During walking, vertical and horizontal excursions of the center of gravity is decreased by `determinants`. The aim of these movements are to increase the efficiency and smoothness of pathway of gait, decrease the vertical and lateral displacements of center of gravity, decrease the energy expenditure, and make gait more graceful. These determinants are pelvic rotation and tilt, knee flexion in stance phase, ankle and foot mechanisms, lateral displacement of the body, subtalar joint inversion-eversion, anteriorposterior and lateral flexions of the body. According to the `dynamic walking` principles, the body acts like inverted pendulum during single leg stance and like pendulum during double leg stance phases during walking. The body consists of locomotor and passenger units during gait cycles. Locomotor unit is responsible from progression, protection of vertical balance, shock absorption and decrease energy expenditure.