A randomised controlled trial of Tai Chi and resistance exercise on bone health, muscle strength and balance in community-living elderly people

Background: the beneficial role of exercise in improving bone mineral density, muscle strength and balance, has been documented predominantly in younger populations. These findings may not apply to elderly populations with limited ability to perform exercises of high intensity. Objective: to examine the effects of Tai Chi (TC) and resistance exercise (RTE) on bone mineral density (BMD), muscle strength, balance and flexibility in community living elderly people. Design: randomised controlled trial, using blocked randomization with stratification by sex. Setting: a community in the New Territories Region of Hong Kong, China. Subjects: one hundred eighty subjects (90 men, 90 women) aged 65-74, were recruited through advertisements in community centres. Methods: subjects were assigned to participate in TC, RTE three times a week, or no intervention (C) for 12 months. Measurements were carried out at baseline, 6 and 12 months. Analyses of covariance (ANCOVA) adjusted for age, and baseline values of variables that were significantly different between groups: i.e. smoking and flexibility for men; quadriceps strength for women. Results: compliance was high (TC 81%, RTE 76%). In women, both TC and RTE groups had less BMD loss at total hip compared with controls. No effect was observed in men. No difference in either balance, flexibility or the number of falls was observed between either intervention or controls after 12 months. Conclusion: the beneficial effects of TC or RTE on musculoskeletal health are modest and may not translate into better clinical outcomes.