Effect of 12 Weeks of Tai Chi Training on Soleus Hoffmann Reflex and Control of Static Posture in Older Adults

• DOI: 10.1016/j.apmr.2010.12.043
• Publication Date: 2011-06-09T05:09:50Z
• Authors: Yung-Sheng Chen; Shi Zhou; Colleen Cartwright
• Keywords: H-reflex

To investigate the effect of 12 weeks of Tai Chi training on soleus (SOL) Hoffmann reflex (H-reflex) modulation and postural control in standing under 4 sensory conditions in older adults.Experimental research design with pre- and posttraining tests in a training group and a control group.University biomechanics laboratory.Community-dwelling older adults (N=34) were assigned to a training (n=20; mean ± SD age, 72.9±4.4y) and a control (n=14; mean ± SD age, 72.9±6.5y) group.Tai Chi participants attended a 1-hour session of Yang style Tai Chi, 3 sessions a week, for 12 weeks, while control participants maintained their regular daily activities during the same period.SOL H-reflex (maximal amplitudes of H-reflex [H(max)] and M-wave [M(max)] waves) and mean displacement of the center of pressure (COP) in the anterior-posterior (COP(A-P)) and medial-lateral (COP(M-L)) directions were measured during bipedal standing, with the feet placed on a forceplate and the heels 6cm apart, under 4 sensory conditions: stable surface with eyes open, stable surface with eyes closed, unstable surface with eyes open, and unstable surface with eyes closed.SOL H(max)/M(max) ratio in the Tai Chi group was upregulated significantly in all 4 sensory tasks after the 12-week Tai Chi training (P<.05). No significant change in COP measurements (mean displacement of COP(A-P) and COP(M-L)) was found in either the Tai Chi or control group after the 12-week period.An increase in SOL H(max)/M(max) ratio during static postural tasks is observed after 12 weeks of Tai Chi training in older adults under all 4 sensory conditions. However, training-induced changes in H-reflex were not accompanied by improvement of performance in the static postural control tasks.