Kinematic Analysis of Lower Body During 90-Degree the Islamic Republic of Iran's Military Marching

90-degree marching is a kind of military marching that can be analyzed as a special type of gait. The purpose of this research was kinematic evaluation of lower body in 90-degree marching based on one- segment model of the leg.

Subjects of this study were 13 Imam Hossein University Students performing 90-degree military march at self-selected speeds recorded by a high speed camera at 300 fps from the sagittal plane. Two passive markers were placed on hip and ankle of the participants and the direct distance between these two markers was defined as leg. Kinematic of the leg, hip and ankle movement in a complete cycle of marching was analyzed using the motion analysis software.

The profiles of displacement, velocity and acceleration to angular movement of the leg and curvilinear movement of the ankle were presented and analyzed. Average propulsion velocity was 0.60±0.14m/s. The leg angular acceleration curve had three peaks and the profiles of vertical, horizontal and resultant acceleration of the ankle showed three, five and one important peaks relatively. 90-degree marching was described based on these peaks which were the movement characteristics.

90-degree military marching at self-selected speed is consisted of stance and swing phases. In support phase, the leg rotates on the ankle as an inverted pendulum. In swing phase, following an initial acceleration, the leg goes up and come down during a pendulum movement around the hip. The moment of impact with the ground is the critical instant which may impose big accelerations to leg.