There have been many medical studies researching the efficacy of Tai Chi both in Australia and overseas. Here are links to a few if you would like to read further about the benefits of Tai Chi.
Dr Paul Lam has been involved in many studies incorporating his Tai Chi for Health programs. This list includes 35 peer reviewed studies and articles on Tai Chi including Tai Chi for Health, Tai Chi for Arthritis and Falls Prevention and Tai Chi for Diabetes.
Song, Lee E, Lam P, Bae S. Effects of Tai Chi exercise on pain, balance, muscle strength, and physical functioning in older women with osteoarthritis: A randomized clinical trial. Journal of Rheumatology. Sept 2003. 30:9 page 2039-2044.
Amanda M. Hall, Chris G. Maher, Paul Lam, Manuela Ferreira, Jane Latimer. Tai Chi Exercise for Treatment of Pain and Disability in People With Persistent Low Back Pain: A Randomized Controlled Trial. Arthritis Care & Research. Vol. 63, No. 11, November 2011, pp 1576–1583
Alexander Voukelatos, MA (Psychol), Robert G. Cumming, PhD, Stephen R. Lord, DSc,and Chris Rissel, PhD. A Randomized, Controlled Trial of tai chi for the Prevention of Falls: The Central Sydney tai chi Trial. JAGS 55:1185–1191, 2007