Tai chi is usually thought of as, you know, a nice way for your grandma to fight osteoporosis. But in the new international trailer for "Man of Tai Chi," Keanu Reeves is using it to fight something a little more dangerous: Killer kung-fu assassins.

Now just think how dangerous he'll be when he masters yoga.

Seriously, though, it's no stretch to think of tai chi in more militant terms. After all, while the form is mainly used as an exercise technique these days, it's based on an ancient Chinese martial art. So violence is inherent in its beautiful motions.

And that's key to the plot of "Man of Tai Chi," which actually features Reeves as a villain who gets his jollies making people fight each other to the death. His latest twisted plan? To take someone dedicated to the gentle art of tai chi (star Tiger Hu Chen) and warp him into a deadly killer.

Reeves doesn't just play the heavy, though; he's also making his directorial debut in this mostly Chinese-language film. Exactly when "Man of Tai Chi" is going to be released in U.S. theaters is still up in the air, but for now, here's the trailer, courtesy of The Hollywood Reporter.

Just don't forget to stretch before you watch it.