Impact of tai chi on impairment, functional limitation, and disability among preclinically disabled older people: a randomized controlled trial.

OBJECTIVES

To test the effect of tai chi on the progression of preclinical disability to manifest disability compared with seated flexibility exercise, and to examine whether tai chi mediates delayed disability by reducing impairments in musculoskeletal, cardiovascular, and neurologic systems, and related functional limitations.

DESIGN

Multisite parallel group individually randomized controlled trial.

SETTING

General community.

PARTICIPANTS

Preclinically disabled community-dwelling people older than 70 years (n=503), without major medical conditions or moderate to severe cognitive impairment.

INTERVENTION

Modified Sun style tai chi exercise compared with seated flexibility exercise, both programs delivered in groups for 60 minutes twice weekly for 24 weeks.

MAIN OUTCOME MEASURES

Disability measured with the Late-Life Function and Disability Instrument. Secondary outcomes were impairments and functional limitations of the musculoskeletal, neurologic, and cardiovascular systems.

RESULTS

There was little change within or between the 2 groups. The mean change in the Disability Frequency Score was 0.3 and 0.1 points (100-point scale) for the intervention and control groups, respectively (adjusted difference -.21; 95% confidence interval [CI] -.99 to .56). The mean change in the Disability Limitation Score was -0.1 and -.04 points for the intervention and control groups, respectively (adjusted difference -0.6; 95% CI -2.31 to 1.11). There was little effect on impairments or functional limitations. A higher proportion of intervention participants ceased attending the exercise program (difference=17.9%, 95% CI 9.6-25.8). Multiple imputation of missing data did not change the results.

CONCLUSIONS

Modified Sun style tai chi did not have an impact on impairment, functional limitations, or disability in preclinically disabled older people when delivered for 24 weeks. Withdrawal from the exercise classes was high but did not explain the null result. Improved compliance, or a longer or more intensive program, may be required.