| The purpose of this study is to investigate the kinematics and kinetics characteristics of the lower extremity during Tai Chi exercise and the postural balance of practitioners at different stages during their years of training.; In this cross sectional study, 15 male Tai Chi practitioners were recruited. Subject: were divided equally into 3 groups in accordance with the number of years they had been training in Tai Chi. The numbers of years of training of the subjects in Group 1, Group 2 and Group 3 were 2.4 ± 0.7, 5.4 ± 0.6 and 18.2 ± 9.7 years respectively. All the subjects were requested to practice the Tai Chi form “Brush Knee Twist Step” in five trials. A balance test was performed with eyes-closed and opened in single and double leg stance. A force platform (Kistler 9281CA, Switzerland) was employed to measure the COP movement in the balance test. In the Tai Chi movement analysis, three-dimensional movement kinematics and ground reaction force were measured and then employed in the inverse dynamics equation to calculate the lower extremity joint forces and moments. ANOVA was applied to examine the differences in the selected parameters between subject groups.; In the results of the balance test, Group 3 subjects achieved significantly longer time in a single leg stance with eyes-closed than Group 1 subjects (p < .05). Analysis of Tai Chi movement indicate that the total movement time in Group 3 was significantly longer than Group 1 and Group 2 (p < .05). Further investigation indicated that the double leg support time of the Tai Chi movement in Group 3 was significantly longer than in Group 1 and Group 2 (p < .05). The results on lower extremity kinematics show that the subject in Group 3 had a significantly larger range in knee abduction/adduction than in Group 1 in Phase 5 of the Tai Chi movement (p < .05). (Abstract shortened by UMI.)... |
