Age-related differences in Tai Chi gait kinematics and leg muscle electromyography: A pilot study

Objective: To compare the biomechanic features of Tai Chi gait by elders with those by young adults, and with those of normative gait. Design: Cross-sectional study. Setting: Laboratory-based testing. Participants: Young (n=6; 3 women) and old (n=6; 5 women) Tai Chi practitioners. Intervention: All subjects had practiced Tai Chi for at least 4 months. Main Outcome Measures: Spatial, temporal, and leg muscle electromyography during Tai Chi gait and normative gait. Results: The primary age-related differences in Tai Chi gait were during single stance, with elders having significantly shorter single-stance time (-50%), less lateral displacement (-30%), knee flexion (-42%), hip flexion (-39%), activation time in the tibialis anterior (-13%), soleus (-39%), and tensor fascia lata (TFL) (-21%), activation magnitude in the tibialis anterior (-39%), and coactivation time of the tibialis anterior and soleus (-47%). Compared with normative gait, elders during Tai Chi gait had significantly larger knee (139%) and hip (66%) flexions, longer duration (90%-170%) and higher magnitude (200%-400%) of the tibialis anterior, rectus femoris, and TFL muscle activities, and longer duration of coactivation of most leg muscle pairs (130%-380%). Conclusions: The elders practice Tai Chi gait in higher posture than younger subjects. The Tai Chi gait poses significantly higher challenges to elder's balance and muscular system than does their normative gait.