Neural mechanisms underlying balance control in Tai Chi

The efficacy of Tai Chi (TC) to improve neuromuscular response characteristics underlying dynamic balance recovery in balance-impaired seniors at high risk for falling was examined during perturbed walking.

Twenty-two subjects were randomized into TC or control groups. Nineteen subjects (68-92 years, BERG 44 or less) completed the study. TC training incorporated repetitive exercises using TC's essential motor/biomechanical strategies, techniques, and postural components. Control training used axial exercises, balance awareness/education and stress reduction. Groups trained 1.5 h/day, 5 days/week for 3 weeks. After post-testing, controls received TC training. Subjects walked across a force plate triggered to move forward 15 cm at 40 cm/s at heelstrike. Tibialis anterior and medial gastrocnemius responses during balance recovery were recorded from electromyograms. Four clinical measures of balance were also examined.

TC subjects, but not controls, significantly reduced tibialis anterior response time from 148.92 +/- 45.11 ms to 98.67 +/- 17.22 ms (p < or = 0.004) and decreased co-contraction of antagonist muscles (p < or = 0.003) of the perturbed leg. All clinical balance measures significantly improved after TC.

TC training transferred to improved neuromuscular responses controlling the ankle joint during perturbed gait in balance-impaired seniors who had surgical interventions to their back, hips, knees and arthritis. The fast, accurate neuromuscular activation crucial for efficacious response to slips also transferred to four clinical measures of functional balance. Significant enhancement was achieved with 3 weeks of training.