The effect of Tai Chi exercise on strength, strength ratios, and postural control in older adults
Crowley-McHattan, Z & Zhou, S 2012, 'The effect of Tai Chi exercise on strength, strength ratios, and postural control in older adults', in K Tucker, B Butler & P Hodges (eds), Neuroplasticity, motor control, cutting-edge technology & rehabilitation: Proceedings of the XIXth Congress of the International Society of Electrophysiology and Kinesiology, Brisbane, Qld., 19-21 July, University of Queensland: School of Health & Rehabilitation Sciences & Centre of Clinical Research Excellence in Spinal Pain, Injury & Health, Brisbane, Qld. ISBN: 9780646582283
INTRODUCTION: Tai Chi (TC) is a traditional Chinese exercise that has become popular among many older populations as a form of exercise to improve health and physical wellbeing. The simple, soft, and fluid movements of TC are performed in a semi-‐squat posture that can place large loads on the muscles of the lower extremities which has been demonstrated to cause significant improvements in the neuromuscular and somatosensory systems. This has led to TC being declared an important exercise in the development of postural control and hence, become important in the areas of falls prevention and healthy ageing.
AIM: To investigate the efficacy of 12 weeks of Tai Chi practice on the lower limb muscular strength, strength ratios, and postural control in an older population.
METHODS: Twenty four older adults (72.0 ± 4.2 years) underwent 12 weeks of Tai Chi exercise (TCG) and fifteen were allocated into a control group (73.9 ± 4.1 years) (CG). Maximal isometric muscular strength (MVC) assessment of knee extensors (KE), knee flexors (KF), ankle plantarflexors (AP), and ankle dorsiflexors (AD) was conducted while surface electromyography (sEMG) was simultaneously recorded during each trail. Maximal sEMG amplitudes were measured along with antagonist coactivation levels. The Hamstring to Quadriceps Ratio (HQR) and Dorsiflexor to Plantarflexor Ratio (DPR) were calculated from these MVC values. Static stabilometry tests were conducted with Center of Pressure (COP) displacements recorded in the anterior-‐posterior (AP) and medial-‐lateral (ML) directions plus calculations of resultant distance (RD). Both Traditional and Diffusion analyses were calculated for all postural data.
RESULTS: All muscle groups of the TCG were significantly stronger post exercise [p0.05]. Only the KE and AP muscle activation significantly increased within the TC group [p0.05]. Only the KF of both groups showed significant changes in activation level when acting as an antagonist (coactivation).There were no significant changes in either the HQR or DPR for either the TCG or CG [p>0.05]. Of the eight postural measures, only mean velocity and sway area exhibited significant reductions post TC [p>0.05].
CONCLUSION: The TC exercise did not effectively attenuate or reverse the age related decline in postural control in this group of older adults. This might however be a product of exercise specificity as TC is a dynamic exercise and the postural control assessment was static. TC was found to be effective in improving muscular strength of the lower extremities of older adults which is often link to greater mobility and improved quality of living.