The worrying thing is that recently the last couple of long runs have gone this way and I have a tough Marathon approaching in 8 weeks time. I'm not sure of the problem, but this is where I need people's help! Any advice big or small would be much appreciated, please leave a comment.
I'll give you a little bit of recent history. You can see below my running for the last couple of months. Have I been doing too many long runs? Not enough of something else?