Check out the National Institute on Agings websites. You'll find tai chi listed as an exercise for balance at
http://go4life.niapublications.org/try-these-exercises/balance/tai-chi
Lots more general info at http://go4life.niapublications.org/ and http://go4life.niapublications.org/
Thanks to Doc Rowe for pointing me to this.
Information of interest to practitioners of tai chi.
