LONG-TERM TAI-CHI AND YUANJI-DANCE TRAINING ON BALANCE AND ASSOCIATED MUSCLE ACTIVITIES IN COMMUNITY MIDDLE-AGED AND ELDERLY

The purpose of this study is to evaluate the sway areas of the center of pressure (COP) and the inclination angles between the center of mass (COM) and COP among elderly subjects with and without training in Chinese traditional exercises, including Tai Chi (TC) and Yuanji-Dance (YD). Additionally, this study investigates the electromyographic (EMG) activities during walking across these groups. The current study employed a cross-sectional study design. Twenty-seven healthy participants aged 45–70 years old were recruited from the local community in this study. TC group and YD group should have regular exercise training for at least two years, respectively. In the first part of this study, each subject of three groups (TC, YD and CON) was asked to walk at a self-selected speed on an 8 m walkway for gait analysis. Maximum center of mass–center of pressure (COM–COP) inclination angles in the sagittal plane and frontal plane were calculated. The EMG activity was recorded bilaterally from four muscles of the lower limbs including quadriceps, hamstring, tibialis anterior and gastrocnemius. In the second part, each subject was guided to perform four tandem static balance tests with the dominant leg leading on a force plate. The time-varying COP positions and the sway area of the COP were calculated from the ground reaction force data. A one-way ANOVA was conducted to compare walking variables between groups, and a two-way repeated measures ANOVA was used to evaluate the effects of group (between-group) and conditions (within-group) on the variables of the static tests. There were no significant differences in the maximum COM–COP inclination angles in anterior– posterior ([Formula: see text] = 0.06) and medial–lateral ([Formula: see text] = 0.15) directions as well as the EMG activities ([Formula: see text] > 0.05) among the TC, YD and CON groups. For static balance test, the TC group showed decreased excursion of COP in anterior– posterior direction and sway area compared with the CON group ([Formula: see text] < 0.01). For the YD group, decreased excursion of COP in the anterior–posterior direction during tandem stance on the soft surface was found ([Formula: see text] < 0.01). Moreover, the YD group showed decreased sway areas of COP compared with the CON group ([Formula: see text] < 0.01). The findings show that the TC group demonstrated smaller sway areas compared to the YD group, indicating that TC training may be especially effective in enhancing the static standing balance. However, there were no significant differences in the anterior–posterior and medial–lateral COM–COP inclination angles during walking among the TC, YD, and control groups. This result suggests that the training effects of TC and YD may not significantly impact the dynamic balance or the muscle activities observed during level walking.