Effects of Tai Chi Chuon on knee extensor muscle strength and balance in elderly women

Background: Some studies have indicated that Tai Chi Chuan (TCC) is capable of improving physical fitness, muscle strength and balance in elderly people. This improvement could prevent falls, fractures and physical dependence. Objective: To investigate the effects of TCC on balance and knee extensor muscle strength among elderly women. Methods: Seventy-seven healthy women who were not engaged in any guided physical activity participated in this study. There were 38 volunteers (68 5 years) in the Experimental Group and 39 volunteers (69 +/- 7 years) in the Control Group. The Experimental Group practiced 24-movement Yang-style TCC for 12 weeks, consisting of 50-minute sessions three times per week. The Control Group did not perform any guided physical activities. Strength was measured using the one maximum repetition test in an extensor chair and balance was evaluated using the unipodal support test with the eyes closed. The statistical analysis consisted of the normality test, split-plot analysis of variance (ANOVA) and Pearson's correlation coefficient. Results: The Experimental Group presented increases of 17.83% in knee extensor muscle strength and 26.10% in balance. The Control Group did not show any significant changes in these variables. No significant correlation was observed between these two variables in the Experimental (r = 0.09; p = 0.554) or in the Control Groups (r = 0,07; p = 0.660). Conclusions: These results suggest that TCC improves knee extensor muscle strength and balance among elderly women, However, knee extensor muscle strength was not necessarily linked to balance in this activity.