RESUMEN
OBJECTIVE: To investigate the effectiveness of tai-chi in preventing falls among community-dwelling older people. DESIGN: Multisite parallel group individually randomized controlled trial. SETTING: Melbourne, Australia. PARTICIPANTS: Preclinically disabled community-dwelling people 70 + years (n = 503), without major medical conditions or moderate to severe cognitive impairment. INTERVENTION: Sixty-minute modified Sun style tai-chi group-based exercise program twice weekly for 48 weeks; control intervention was a seated group-based flexibility exercise program of the same dose. MEASUREMENTS: All falls, self-reported using a monthly calendar, analyzed at 24 weeks and 48 weeks. Injurious falls reported in follow-up telephone interviews for each reported fall. RESULTS: The adjusted fall incidence rate ratios at 24 and 48 weeks were 1.08 [(95% confidence interval (CI) 0.64-1.81)], and 1.12 (95% CI 0.75-1.67), respectively. A higher proportion of intervention participants ceased attendance in the first 24 weeks (difference 17.9%, 95% CI 9.6-25.8), and the second 24 weeks (2.7%, 95% CI -5.0 to 10.4). Intervention participants who ceased attendance had lower left quadriceps strength (difference 3.3 kg 95% CI 0.15-6.36) and required longer to complete the timed up and go test (difference 1.7 seconds 95% CI 0.22-3.17) at baseline. CONCLUSIONS: This study does not support modified Sun style tai-chi as a falls prevention measure among relatively well community-dwelling older people with modified mobility and at increased risk of disability. Insufficient intervention intensity, or low exercise class attendance may have contributed to the lack of effect, as may have attrition bias among the intervention group.