Visual Perception of Biomechanical Characteristics of Walking, Jumping, and Landing

Visual perception of biological systems is one important aspect which has been considered by researchers in understanding human motion. The term «biological motion» was used by Johansson (1971, 1973) to distinguish human movement patterns from the motion of rigid inanimate objects previously utilized in visual motion perception. The emphasis, however, has been on the need for distinguishing three types of motion to describe perceived kinematic relations: the relative motion of elements to each other in the configuration, the common motion of the whole configuration relative to the observer, and the absolute motion of each element in dynamic display [Cutting and Proffitt (1982)]. Based on data collected using a video-recorder, reflective tape and high powered light for producingpoint-light displays, Cutting and Proffitt (1982) concluded that relative motion is automatically minimized by the visual system. Moreover, Johansson (1971, 1973) showed that all movement pattern of walking and running can be visually identified by observers without seeing the total picture. Using a similar technique, observers were able to visually recognize gender and friends by their walking patterns (Cutting and Kozlowzki, 1977; Cutting, 1978), ones' own identity (Beardsworth and Buckner, 1981), the weight of lifted objects (Runeson and Frykholm, 1983), and to the extent that evaluation of technical skill execution was sucessfully judged (Scully, 1986). Based on the principle that relative motion is automatically minimized by the visual system, Johansson (1973), concluded that previous learning of motion patterns do not determine the perception of walking. An important factor, however, is a highly mechanical, automatic type of visual data treatment. In addition, Runeson and Frykholm (1981) stated that the dynamic variable of the event (weight of the box), is well specified in the kinematic pattern and hence the visual system is efficient in picking up such information. Identifying cues by visual information may not be sufficient, however, to distinguish discrete skills (ie., jumping and landing) and/or continuous skills (ie., walking), especially, if the direction of the movement is reversed and if the total picture is seen as an absolute motion which includes the relative and common motion (Cutting and Proffitt, 1982). Therefore, this study was conducted to test the hypotheses that experience and familiarity are important factors in visual perception of kinematic patterns and that kinetics cannot be determined effectively by observation of kinematics. The purpose of this study is to determine: (1) the ability to visually perceive differences between a continuous skill (walking forward vs. backwards): (2) a discrete skill (jumping vs. landing); (3) the actual kinetic differences in the movement; and (4) whether individuals can distinguish between movement patterns, despite the kinetic differences, while the true pattern is reversed.