The upshot was that I hadn't run all week, until this morning.
The thermometer showed 0.1 deg C as I left HF Towers and frost still rimed the fence rails and grass. The sun gleamed feebly white and there was a hint of pink in the sky. My plan called for me to run 2 miles easy and then do 8 x 400m intervals with 400m jog recovery, and then 2 miles easy to finish. And that is what I did. It must have looked very odd to the family out walking their lovely marl collie as I kept plodding past one way and running back the other, but, as runners know, when you're doing an interval session you just block everything out and get on with it. I wasn't going flat out on the intervals, partly because I didn't want to risk my back, and partly because it was very frosty underfoot, so I was moving a little gingerly. It all went well. The back held up well, with only a minor ache on the uphill sections, and my heart rate was roughly where it should be. And it felt very satisfying to have done it. On top of all that - it didn't rain. And it's not often I've been able to say that for the last 7 months.