<title>Variations In Gait Patterns Of Runners: Relationship To Anthropometric Measurements</title>

Abstract

AbstractHigh-speed computerized motion analysis was used to assess the running parameters of a group of runners. Anthropometric measurements were taken on the group of runners in an effort to provide possible correlations between running style, speed, and anthropometry. The most consistent correlation was between speed and stride length. Femur length and stride length was only highly correlated the runners at the fastest speeds. The faster runners also had a gait pattern characterized by significantly lower ground contact time than that of the slower runners. Of prime importance in running is behavior of the body during float phase, and mediated by anthropometry and the biomechanical characteristics of the stance phase.IntroductionAlthough considerable research has been done on the kinematics of running, little attention has been given to the relationship between selected anthropometric measurements and kinematics. Running, like other movements, involves changes in position of body seg­ ments, organized in a particular time-space sequence. Observed kinematic parameters of running appear similar in configuration when examined visually. When examined by the computerized video motion analyzer, the kinematic factors are amplified.Running kinematic patterns are dependent upon velocity, environment, past experience, conditions during early learning of running, muscle strength, reaction time, and the anthropometric factors. Therefore one may envision a central program running which can be activated by cortical action and influenced by various anthropometric factors.One of the more recent studies on human performance addressed the mechanical char­ acteristics of the running surface in an effort to tune the track to the runner! This technique achieved notable success in reducing running times. Of particular interest was the interaction of human body with the track surface to produce float phases of the proper biomechanical characteristics. This was preceeded by a study of the mechanical dynamics of the human body? Other studies are notably lacking in the characterization of the mechanics of the body and the correlation with runnning parameters.MethodThe kinematic pattern of running was assessed in a group of thirty-two runners, all of whom were experienced runners* averaging in excess of fifty miles per week each. At the time of running, the following anthropometric measurements were taken with a simple tape measure: femur length, tibia length, navicular ratio, foot length, anterior superior spine width, trunk length, weight, chest girth, thigh girth, and calf girth.Videotapes were produced at a rate of sixty frames per second with two Sony video motion cameras positioned orthogonally to record frontal and side views of each test subject. These tapes were analyzed by means of sequential programs piped between a Z80A-based micro­ computer and a DEC POP 11/70 minicomputer. The positions of reflective markers at the greater trochanter, the lateral condyle of the distal end of the femur, the lateral aspect of the foot, and the lateral aspect of the fifth metatarsal head were automatically determined by the two-camera system under supervision of a cross-coupling algorithm to correct for magnification and parallax. The following kinematic parameters were taken by programs written specifically this study: linear velocity of selected points on the body, angular velocity of selected points on the body, vertical displacements, angular displacements, stride lengths, stance phase times, and float phase times. Particular attention was paid to these parameters as a function of the three phases of running: ground contact (stance), mid swing (float), and deceleration (prior to ground contact).ResultsSince the data in the computer resulting from the sequential application of the various software is in terms of X, Y, and Z coordinates of selected points of each body, diverse modes of data presentation are possible. For a test subject walking (Figure 1), a stick figure representation shows the various phases of one leg during gait. As the stick figures show, the running body has a well-defined float phase occurring symmetrically about the