Hey there all, thinking about this and the 5 pound challenge I am in has kept me motivated today, hope it can all week!
freethetoys-at 5'11 and 170something I can't imagine your that "big", except in the sence that your tall! I would think you can do whatever you can handle, the only way to know is try and see how your body reacts. Know the difference between exercise pain (ooo I didn't know I had those muscles anymore) and hurt yourself pain (I think I ruptured/tore something)
I am 5'7" and 198 pounds and do kung fu! I also work out with kettlebells and do a kickbox type class (I don't work out that much recently but did a few weeks ago) I think your body can handle whatever your in shape to do + that little bit more that makes the workout worthwhile! Good luck and let us know what you come up with.