A classic tempo run is, apparently, a sustained, comfortably hard effort for two to four miles. And it is designed to teach the body to use oxygen for metabolism more efficiently.
So off I went, at a comfortably hard rate... only problem is, my mind started to wander and I forgot to stop running when I reached the end of the four miles scheduled for today. On I ran for another mile.
And, get this. I ran 5 miles (little over 8 kms) in 53 mins. I feel pretty good about that.

Note to Mummer & EJ... Cheetah! Cheetah! Cheetah!
~