| Purpose:There are many researches demonstrated that postural control could be influenced by ageing. In contrast, physical actives improved posture stability. Many studies reported a better postural control after TC exercise in elderly population, without identify the mechanisms behind the improvement postural control. Therefore, The purpose of this paper were 1) detective of the different of the influence of long-term exercises for postural control during static balance task and dynamic fitting task; 2) the influence of long-term exercises for postural control strategy during dynamic fitting task. Methods:Thirty-six participants aged form 65 to 75 years old were recruited from local community centers. They were accordingly classified into three groups: Tai Chi(TC), Sedentary(SE) and Brisk walk(BW). Participants performed two different tests including the static balance task(30s quit standing with eye open and close) and the dynamic fitting task(standing with upper body movement). There were six conditions, as follows: 1) large opening with arm’s length; 2) medium opening with arm’s length; 3) small opening with arm’s length; 4) large opening with 1.3 arm’s length; 5) medium opening with 1.3 arm’s length; 6) small opening with 1.3 arm’s length. Force plate data was used to calculate center of pressure(COP) of foot for all trails. The posture sway was quantified using of the maximum distance in both the anterior-posterior(AP) and medio-lateral(ML) directions, 95% confidence ellipse area and the mean velocity. Two-way ANOVA with repeated measures was used to identify the association between dependent variables(COP variables) and the independent variables(group, vision) for static balance test. Three-way ANOVA with repeated measures was used to identify the association between dependent variables(COP variables) and the independent variables(group, size and distance) for fitting task. Results:1) For static balance task, no statistically significant was found among the different groups and between EC and EO condition on the maximum distance in the AP direction. For dynamic fitting task, the group(F2, 33 = 11.551, p =.000), distance(F1, 33 = 462.072, p =.000) and size(F2, 33 = 15.136, p =.000) had significant effects detected on the maximum distance in the AP direction. TC group had less maximum displacement in AP direction than SE and BW group for upper body movement condition. Reaching far distance condition leaded to greater maximum displacement than reaching close distance condition in the AP direction. And fitting different openings condition also had significant effects observed in the AP direction. Fitting small opening condition was greater maximum displacement than reaching medium and larger opening condition in AP direction. The distance * group also showed statistical significance in AP(F2, 33 = 14.489, p =.000). Post-hoc test showed that TC group was less maximum displacement than SE and BW group in AP direction;2) For static balance task, no statistically significant was found among the different groups and between EC and EO condition on the maximum distance in the ML direction. For dynamic fitting task, the group(F2, 33 = 4.170, p =.024), distance(F1, 33 = 22.057, p =.000) and size(F2, 33 = 8.044, p =.003) had significant effects detected on the maximum distance in the ML direction. TC group had less maximum displacement in ML direction than SE and BW group for upper body movement condition. Reaching far distance condition leaded to greater maximum displacement than reaching close distance condition in the ML direction. And fitting different openings condition also had significant effects observed in the ML direction. Fitting small opening condition was greater maximum displacement than reaching medium and larger opening condition in ML direction. The distance * group also showed statistical significance in AP(F2, 33 = 4.954, p =.013). Post-hoc test showed that TC group was less maximum displacement than SE and BW group in ML direction;3) For static balance task, no statistically significant was found among the different groups and between EC and EO condition on the 95% COP area. For dynamic fitting task, the group(F2, 33 = 10.63, p =.000) and distance(F1, 33 = 96.467, p =.000) had significant effects detected on the 95% COP area, no statistically significant was found among the different openings. The TC group showed less area than SE and BW group. Reaching different distances condition also had significant effects detected. And distance * group interaction(F2, 33 = 13.643, p =.003)(see figure 6 for details) was observed for fitting task. Post-hoc test showed that TC group had less area than BW group in the fitting close distance condition, and had less area than SE and BW group in the fitting far distance condition;4) For static balance task, no statistically significant was found among the different groups and between EC and EO condition on the mean velocity. For dynamic fitting task, Reaching different distances condition had significant effects observed(F1, 33 = 67.585, p =.000), which means increase in velocity was observed for decreased the reaching distance. Fitting different openings also had significant effects(F2, 33 = 41.306, p =.000), where an increase in velocity for increased the opening size. In addition, distance * group(F2, 33 = 41.306, p =.000) interaction was observed in the fitting task. Post-hoc test observed that TC group was lesser velocity than BW group in the close distance.1) In the static balance task and dynamic fitting task, no significant effects was detected between SE and BW group, which mean long-term BW exercise might ineffective for postural control at upper body movement;2) In the dynamic fitting task, TC group had less maximum distance in both directions and 95% COP area than SE and BW group, which mean long-term TC exercise effective improve postural control, and TC group should performance better than the BW group at upper body movement.Conclusion:... |
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