This paper proposes a computer graphics approach to represent the kinematics of the lower limb during a multijoint coordinated motor task. The methodology is based on automatic digitization by a microprocessor of reflective markers placed on anatomical landmarks and videotaped using a videomotion analyzer and camera. Thus, the investigator can represent complete movement patterns graphically. With joint angles, or the first or second derivative of the angles serving as the coordinates for the three mutually perpendicular axes in R3, the technique gives a point in space corresponding to each time increment as the movement sequence progresses. Using this method, a graphical representation of the position, velocity, or acceleration can be generated in movement space, velocity space, or acceleration space, respectively. A sample of the results of this technique is presented using the movement space of elderly, nonhandicapped, and cerebral palsied individuals as each steps over a low obstacle. The cluster of data points created for each subject are connected to form a three-dimensional graphical representation of the covariation between joint angles. The use of the approach is discussed in relation to future research in neuromuscular coordination using concepts from catastrophe theory. Possible applications for handicapped individuals are mentioned.
Anne Beuter and Alan Garfinkel
In this study, phase plane analysis was used to describe the mechanisms involved in human intralimb dynamics during a multijoint coordinated task. Nonhandicapped, spastic, and athetoid cerebral palsied individuals were videotaped as they performed a stepping task. Kinematic data for the hip and knee joint angles were digitized, smoothed, differentiated, and plotted. Phase plane analysis of movement data reveals striking differences between nonhandicapped and cerebral palsied individuals. Whereas nonhandicapped individuals have trajectories in the phase plane that suggest a self-contained second-order dynamical system, cerebral palsied individuals have self-interesting loops in their phase planes. Based upon these patterns some dynamical distinctions are offered, and suggestions are made toward a possible model.
Anne Beuter and Joan L. Duda
The purpose of this interdisciplinary study was to assess the impact of arousal on motor performance by examining the kinematic characteristics of a stepping motion in high and low arousal conditions on 9 subjects. Raw data were recorded from a rotary shutter video camera and digitized automatically by interfacing the videomotion analyzer with the digitizing board of a microcomputer. Three-dimensional orbital plots of the hip, knee, and ankle angle covariations revealed that the subjects used two different strategies to perform the skill. Phase plane analyses revealed a tight coupling between joint position and velocity in both conditions for the hip and the knee. Differences in movement kinematics between low and high arousal conditions were most visible in the ankle joint whose phase planes displayed an increased number of self-crossings (loops) in the high arousal condition. It was suggested that under high arousal, what was once automatic and smooth in terms of the ankle joint now comes under more volitional control, which is less smooth and efficient. Practical implications of the present study are suggested.
G. Lawrence Rarick and Anne C. Beuter
This paper is an account of a field research project on mainstreaming two age levels of TMR children in physical education classes, including a commentary on pedagogical considerations in mainstreaming. The findings indicated that the gain in motor performance of the integrated generally exceeded that of the nonintegrated TMRs without adversely affecting the performance of their nonhandicapped peers. Teacher intervention was greater for the young retarded than for their nonhandicapped peers, more apparent for the integrated than for the segregated TMRs, and less evident for the older nonhandicapped than for the older TMR children. The findings lend support to the belief that the retarded can be successfully integrated in physical education classes.