In 1982 I was introduced to a fellow who taught "combat tai chi"
It was inessence a remodeling of the way tai chi was used.
full contact, full force pulls, throws, pushes, grabs, takedowns...pretty cool stuff.
since then, i don't give credo to tai chi as health exercises much, but i can respect it as any exercise is better than none and I see improvement in mobility with those seniors I know who have undertaken practice of it.
qigong is as good as tai chi in that respect.