Characteristics of the studies included in the meta-analyses.

No. = number; TC = Tai Chi; RCT = randomized controlled trial; wk = week; UPDRS = unified Parkinson's disease rating scale; BBS = berg balance scale; TUG = timed up and go; 6-MWD = 6-minute walking distance; TST = tandem stance test; OLST = one leg stance test; FRT = functional-reach test; NR = no reported; Non-RCT = non-randomized controlled trial.