BIOMECHANICAL ANALYSIS OF PERFORMANCE IMPROVEMENT IN AIMING MOTOR TASKS

Abstract

INTRODUCTION: The improvement of performance is closely related to specific modifications of the kinematics and the myoelectrical parameters of each aiming motor skill. The purpose of this study was to determine the modifications of selected kinematic and myoelectrical parameters which resulted in the improvement of aiming performance. METHODS: Seventy volunteers practiced a novel throwing skill which involved the throw of a ball performing elbow flexion. Kinematics were computed through film analysis at 80Hz. Furthermore, the surface ectromyograms of four muscles in the elbow region were analyzed to determine the changes in the timing and the intensity of muscle activation which may be accounted for improved performance. The correspondence analysis was employed for the evaluation of the data. RESULTS: The results revealed that performance enhancement was related to the decrease in the time and the displacement of the movement. Practice also resulted to significant modifications in the electrical activity of the muscles. The number of the active muscles was diminished and the agonist activity was reduced. The antagonist activity was increased but it was presented significantly farther from the beginning of the movement after practice. CONCLUSION: Practice brought about specific modifications in the muscular contribution to the throwing task, by means of a reduction in the electrical activity of the primary antagonistic muscles during the movement. These modifications gave rise to specific alterations in the physical aspects of the skill, which directly resulted in improved performance.