Take Fridays for example...
My coach likes people to work off a Tuesday / Friday cycle for the harder runs. On a number of separate occasions I've pitched up at the track after work Friday ready for my session and body has just not wanted to play.
Today, after a stress free and relaxed day at work I managed to get some work experience visits completed early and went up there for my session. Did the warm up and first set and it just wasn't flowing. Dug in hard to maintain goal pace but drifted out to 2 secs / lap slower before end of the first set.
The stupid thing is, I'll go back up there tomorrow and it will flow like a fine wine.
Odd thing is there's also been occasions I've crammed the session in on Thursday instead and nailed it.
What is it about Fridays I wonder...