Just got the Mar. '06 issue of Black Belt magazine. There is an article by Jim Wagner regarding this very topic. I'm not going to post the entire article, but I will address certain points he made.
1: he states that its nonsense to think that a hand will be broke if a closed fist is used, stating that fingers can be hyperextended.
Well, if they're curled back, the way they should be, that won't happen.
2: When he hits someone, the last thing he is thinking about is the injury inflicted on his opponent. So what if I sprain my hand, I can still fight with those injuries.
Well, depending on how bad the injury is, that will determine if you can still use it or not. Coincidentally, I was doing focus mit drills last night, threw a hook, and hurt my wrist. Now, that was my own fault, for not having my hand in the proper position, but one the less, it hurt like hell!!! I still continued with the drills...stuipd I know...but changed to an open hand palm strike in place of the hook. I still got some damn good power from it too!!
3: He then talked about stopping power. You're going to get more power with a closed fist. The power will dissipate, etc etc.
While I may not get that KO with that 1 shot 1 kill mentality, that is not what I'm looking for. When it comes to SD, I don't want to gamble with thinking like that. Can it happen? Sure, but I'm not going to take my chances. If I can hit the jaw with a closed fist, I can move a bit higher and target the ear with the open palm.
Mike