OK, i need to get the 'Ultimate Back Fitness..' to explore this further.
I'm still not sure what leads from the recommendation (in LBD's) to avoid sit up/ leg raise type movements because they are essentially training the abdominals at the expense of the spine, to having them be acceptable.
Other thoughts of mine are is it possible that people who aggressively train such movements tend to be athletes who will then retire from such training while still relatively young. Therefore we do not really see a large amount of what results from training such movements throughout life?
Kind of like saying a packet of cigarettes won't do much damage but keep smoking for long enough...(if that makes any sense whatsoever)?
I believe there have been studies that show competitive weightlifters have less back problems than the general population. Have similar studies been done on other athletes - gymnasts?