Today I had planned a tempo run of 2 x 18 minutes @ 4:30/km with 4 min. recovery in between but had been feeling sluggish and tired all day and kept postponing the run, doubting I could do it.
When I finally got outside, I started with a 10 minute warm up jog then began the first 18 min segment, it felt pretty hard and as I was approaching the last couple of minutes I had decided to scrap the last 18 min. run.
The recovery jog left me feeling ok though and when my watch beeped that it was time to turn up the speed again, I was determined to run as much of the last segment as I could.
To my surprise I now felt great, I kept around 4:27/km pace and actually passed 10km 30 seconds faster than my 10K PR.
It's funny how running is sometimes, I was absolutely sure that it would be a crap run but everything just clicked in that last 18 min and it was one of the best I've had in a long time.