The Relationship between Posture Stability and One-hand Catching

Abstract

The purpose of this study was to explore the relationship between postural stability and one-hand catching from the perspective of relative proficiency of the two motor skills and the influence of the secondary task. Nine right-handed and one left-handed female college students majoring in physical education without prior experience in standing on the stabilometer participated in this study. All the participants practiced on the stabilometer 20 trials a day (each trial lasted for 30 seconds), 3 days a week for 4 weeks. Balancing time and number of balls caught were examined for the pre-test, mid-test, post-test and one-month retention-test, which included standing on the stabilometer only and those plus one-hand ball-catching (with preferred and non-preferred hand). The movements of the stabilometer were captured by a PhaseSpace motion digitizing system to derive the frequency and the amplitude of the platform. The results were as following: 1. The balancing time significantly improved with practice, F(subscript (2.37, 21.29))=91.02, p<0.5, the continuing improved postural stability was observed through the addition of the secondary task of one-hand catching. 2. Although there was no difference between the preferred and non-preferred hand in the number of balls caught on the stabilometer at all tests, F(subscript (1, 9))=0.17, p=0.687, there were significantly more balls caught with non-preferred hand while standing on the ground than standing on the stabilometer at pre-test, t(subscript (9))=2.39, p<.05. 3. The frequency of the platform significantly increased and the amplitude significantly decreased after practice. To sum up, posture stability could be considered as a more skilled task when performing another task, and its importance required a secondary task to reveal. The less familiar skill would be easily subject to the perturbation of the imposed task when 2 tasks were asked to perform simultaneously. The improvement of the unfamiliar skill could lessen the perturbation effect of the imposed task.