“This systematic review update includes 54 randomised controlled trials and confirms that exercise as a single intervention can prevent falls…
Both home-based and group-based programs have been shown to prevent falls. Group-based Tai Chi has been found to be effective for falls prevention in several trials.”
http://www.publish.csiro.au/?act=view_file&file_id=NB10056.pdf
Sherrington, Catherine, Anne Tidemann, Nicola Fairhall, Jacqueline C.T. Close, and Stephen R. Lord. “Exercise to Prevent Falls in Older Adults: An Updated Meta-analysis and Best Practice Recommendations.” NSW Public Health Bulletin 22 (2011): 3-4. Web.