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.
Both authors have contributed equally to this paper. The authors would like to express their appreciation to Jay Kimiecik for his assistance in data collection. Partial funding for this study was provided by the Faculty Research Innovation Fund at the University of Southern California.
Requests for reprints should be sent to Anne Beuter, PED 107, University of Southern California, Los Angeles, CA 90089-0652.