Set off to run to my cousin's house today in Harrogate (13ish hilly miles). One mile in and had to return home with a slight pull in my right hamstring. I don't think it's too serious, but I certainly couldn't have run on it.
Returned home to get my bike and cycled instead as this didn't seem to bother it at all, so at least got in some kind of workout, although it wasn't the nice run I'd had in mind.
I will do some more cycling tomorrow instead of the long run and rest the leg until midweek and see how it is then. I am trying to be philosophical about all these setbacks, but they are a bit depressing.
With hindsight, Tuesday's sprint session was the cause. I came back after a few days out and went straight into a hard sprint/pyramid session. My hamstrings felt very tight afterwards, but as I had such a good run on Thursday night, I thought I was out of the woods. They must have been tighter than i thought. I think with the intensity of the running I am working up to, I will give the tempo runs a miss and concentrate on hill reps instead.