because it's movement guys, get over it: intentioned, conscious, parasympathetic activating movement, often with 80 to 100% weightbearing on a single lower extremity, which, among other things, is going to have a big impact on lymphatic drainage of the lower quarter and balance capacity will improve dramatically as well, especially in the group most studied for that effect, namely geriatric population, which is going to stand to have the most dramatic statistical gains in balance because they are in general doing poorly in that area to begin with;
and it's
social - show me it gets the same effects if people were made to practice alone instead of in a group, that would be surprising...
nothing wrong w/taiji as such, but there's nothing that special about the form or moves
per se from a therapeutic perspective; I would bet good $ that if you took a group and taught then "placebo" taiji (e.g. - a made-up form, for example), you'd have the same results;
research is good, but there's a common denominator here that has not yet been explored, and I would suggest it's a research bias that ignores it...
let the hating commence