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Aswad -> RE: Punching your sub/slave? (7/5/2007 3:56:32 AM)
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quote:
ORIGINAL: PeggyO
Based on the medical information I have gotten from medical professionals, the blow has to be delivered specifically above the left ventricle and the window of the timing of the blow is approximately 15 ms.
Okay, that's different from what I got.
Looking at WP for reference (admittedly a poor choice for medical issues), the notion is that of delivering 50J or so to the sternum at the right height, within a window of 10-30ms per beat. Note the last part. Assuming the recipient is all hot and sweaty, as high as 90-something bpm is not unlikely, giving a beat duration of about 650ms.
Using your figures (15ms), that means 2.3% of the time, the heart is in a vulnerable phase.
That translates into something more like one-in-fifty.
Now, again, WP is a poor source, but it indicates 50J is enough, if you get the area approximately right. It also indicates that hitting the area more precisely, or hitting at a more unfortunate angle, will lower the impact needed. This (50J) is about a half-strength punch for an untrained, average-fit person, if I remember my sports figures, while a top trained fighter using proper skeletal alignment could deliver slightly over 1KJ, compared to about 3KJ for a 7.62mm round, or about 450J for a 9mm parabellum round. Attempting to deliver that kind of impact pretty much qualifies for the Darwin Award, though.
Of course, if you'd like to check up on the sources, that would be lovely. I'm no cardiologist, as I said, so the only checking I've done is having a look at WP half a minute ago.
quote:
I don't know where the 1 in 40 number comes from - if it were accurate then we'd have a lot of dead folks around.
I dunno. I see a bit of sparring and such. It's not exactly often that people deliver a significant impact to the correct part of the sternum during training. As I said, a blow to the sternum should break cartilage at the very least, and compress the thoracic cavity, which in itself poses a cardiac risk for entirely different reasons.
But, yeah, it does seem to be somewhat unlikely for a random blow. Unless the sources used by WP are off, though, the slightly lower figure of one in fifty should be correct for those blows that land right. All I said, though, was not to do that; for an untrained person to start punching that part of the sternum hard enough to knock the wind from a person, for fun, seemed an unnecessary risk until the parties had done the research themselves.
Note that I had no reference for the strength of the blow, save that it knocked the wind from her.
Striking toward the celiac plexus at a somewhat upward angle while the abdominal muscles are relaxed is, as I am sure you know, something that can easily be done in a way that minimizes risk and gives a fair bit of shock effect, the latter being what she gave as the reason for the turn-on. It can also upset the diaphragm temporarily, with an effect that I guess one can describe as having the wind knocked out of oneself. From what you (or was it someone else?) said earlier, there should be no danger in striking there, as opposed to some small danger in hitting the sternum for the same effect (which takes a considerably stronger punch).
Hence, my advice.
If you still feel it's bad advice, then I have nothing to counter that, and stand corrected.
quote:
Also, the injury you described in the dojo sounds like something other than Commotio Cordis, which is a spontaneous stopping of the heart.
As I also commented.
Note that I also said that, in the dojo, it seems to me like most blows to the sternum would be more like this: an accident, where either a combat blow is dealt, or a training blow hits the wrong area. In either case, the result is the same: broken cartilage and/or bone, along with thoracic compression. Commotio cordis is rather irrelevant in that context, I would imagine, and thus wouldn't show up on statistics, since it would be hard to discern whether timing or trauma was the actual cause involved.
Low impact sparring, like practiced in many mainstream dojos, doesn't have enough force to cause commotio cordis in the first place, going by either what you said, or what WP said. This is also the most common case where children are involved, and those are the most vulnerable ones, given their relatively lower absorption of the impact. (Though there is a disease which weakens the sternum, whose name escapes me; an untrained Dom might not remember to check for that.)
quote:
There was a post on the Diva Midori list about commotio cordis that details this information. While I do not have permission to repost it here, here is the link to the list http://groups.yahoo.com/group/divamidori/. Do a search on Commotio Cordis and you can see the entire thread.
Thank you for that link, I'll have a look at it.
Please note that I was not criticizing the use of punching and kicking as play, merely suggesting that it would be a good idea to do a bit of basic research, and saying that I wouldn't do it, for reasons unrelated to any perception of risk on my part, as already outlined in previous posts.
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