Interesting to read some of the previous comments and I'd like to wait and see what effect the GMR has had on the turnout for the YMCA event. I for one would not have normally considered trekking over the Pennines for the YMCA race, especially when there's a race much closer to home on the same day, but having run the GMR yesterday I feel compelled to have another crack at a road race in Manchester to see if I can better my time.
Yes running can most definitely cause back problems and I speak from experience!
I had weeks of unsuccessful treatment for what I thought was a thigh strain, but in reality the problem was a pinched femoral nerve in my back which was referring pain into the thigh area.
The reason for the pinched nerve was a bio-mechanical problem in my hip causing me to over-rotate as I ran. I was only able to sort this out with a proper gait analysis and some very specific stretching and mobility exercises.
I would urge anyone who has pain which seems not to be responding to conventional treatment to consider the back as being at the cause of the problem.