A systematic review of seven randomised controlled trials has concluded that tai chi has the potential to reduce falls or risk of falls among the elderly, provided that they are relatively young and non-frail. (A systematic review of the effectiveness of Tai Chi on fall reduction among the elderly. Arch Gerontol Geriatr. 2008 Apr 15. [Epub ahead of print]).

The mechanisms by which tai chi can improve balance were investigated in a randomised controlled trial of 49 healthy older adults. The investigators found that that a widening of stance and improved use of vestibular input (sensory information from the inner ear which informs us how the body is moving in relationship to space and gravity) are two mechanisms by which tai chi may improve balance. (Effect of combined Taiji and Qigong training on balance mechanisms: a randomized controlled trial of older adults. Med Sci Monit. 2007 Aug;13(8):CR339-48).

A large Australian study of 702 healthy people (mean age 69) has concluded that a 16-week programme of tai chi classes improved their balance and reduced the incidence of falls. (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):1185-9 ).