Injuries are part of fighting, and certain practitioners are more likely to hurt themselves in certain ways than others, depending on hte manner of the strike, and how the power is generated.

I've seen four or five separate videos "(tracked 3 down) of legs breaking in half during round kicks to an opponent's leg.

It's really, really, gross, so only look if you wish to:

http://www.youtube.com/watch?v=sDR4i_4DeC8

http://www.youtube.com/watch?v=zxgC6S9oUKE

http://www.youtube.com/watch?v=4W5RI3peGLY
(2 mins. in)

I am curious to know whether any of you have seen this firsthand, whether this is somewhate common, and whether it points out a serious flaw in using the shin for kicks that might be a little too hard for practicality. I'm not really trolling, I swear. But in kung-fu, I don't ever recall hearing anyone discuss a shin kick. Sometimes people do them in sparring, but I've never heard them discussed, by a teacher, as a good kicking surface.

Kicking with the foot: obviously, breaks happen. But I wouldn't call them crippling breaks, for the most part. It depends on where the break occurs. If you were fighting, you still have a chance of surviving the encounter, or hobbling away, etc. But here.....holy crap, that has to hurt......I feel bad for those guys, and as grossed out as their opponents were.

For the sake of discussion: Here we have 3 videos of practitioners making clean, crippling breaks to the shin, where the bone is completely severed, and hte foot is just dangling inside a kind of flesh-sock. We can assume that if something's been caught on national TV at least three times in a ring fight, it has to happen much more on a wider circuit, in training dojos, amateur fights, sparring sessions.

I've also seen that leg kick break someone else's leg.

Is it a flaw in the kick, the way it was used (where on the shin to make contact), or in the practitioner (not enough conditioning of bone density to take that kind of contact)?

Discuss, if this is in any way interesting.