In my Matt Roberts Get Running schedule for today it says "we're now throwing in a few sprints for some serious speed and fun".
Er..Hello?!
First of all, sprinting is not fun, it's a nausea inducing pain fest; and B, are you crazy??!!
I'm so far the wrong side of forty I'm only just the right side of fifty, with a dodgy right hip and a dodgier left ankle and can't start the day without an inhaler; and you want me to sprint? And for fun?
NO!!
No,no.no,no,no,no,no! Pas de sprinting! EVER!!!

I think I shall have to write my own book -
Running for the Unfit Forties.
Chapter 1: Don't.
The End.