Hmmm....coming in late so I'm addressing the original question:
it is clear that accidents and injuries WILL happen.
A certain percentage of acute inuries are serious enough that, in and of themselves, they will result in some form of ongoing disability or chronic ailment/injury.
HOWEVER, I do believe, as somebody who trains in aikido, and has been a RN over 20 yrs, that many many chronic injuries in aikido and in life itself were preventable were they appropriately treated when they were acute injuries.
In aikido we see this a lot with soft tissue injuries, esp tendons, that sustain a minor insult. But nobody wants to stop training. So put on some tape or a splint instead. Ice and elevation is all very good. But I work full time and its too much bother to figure out where to store a cold pack on the job, so I'll just ice it after work, before I head to the dojo.
Yeah, I twisted my neck, but....
Yeah, my pinkie is broken, but....
well we each have one body. There is enough stuff we have no control over. We DO have control over how we treat our acute injuries.
rant mode off :-)