OK, this is starting to look grim. The low back is really not going as well as I would like. I have been working daily on exercises while keeping the running going. I have tried modifying the way I run, but to no avail. The next step is going to have to be physiotherapy. I have even resorted to the MBT shoes (there is a lot of good info and debate on these their). These shoes strangely call themselves the anti-shoe that mimics barefoot walking yet are the most bulky shoe I have ever seen. I guess that is just marketing hype. There is also a lot of info on if the MBT shoes actually work. I reached the conclusion that they do alter the posture and in some cases, that can be a positive thing and in others that can be a negative think, so I guess I got nothing to lose by trying. Its appears that adapting to MBT shoes is important and the transition needs to be careful. The marathon is a no go if I cannot get on top of this problem. I will let you know what happens.