A randomized, controlled trial of tai chi for the prevention of falls: the Central Sydney tai chi trial.
“Falls were less frequent in the tai chi group than in the control group…Participation in once per week tai chi classes for 16 weeks can prevent falls in relatively healthy community-dwelling older people.”
http://www.ncbi.nlm.nih.gov/pubmed/17661956
A randomized, controlled trial of tai chi for the prevention of falls: the Central Sydney tai chi trial. J Am Geriatr Soc. 2007 Aug ;55(8):1185-91.