AND--- if you are not careful to maintain form as you take off, and especially slow down, the pure nature of getting youirself this pumped is prone to injury.
but- to the OP
what ios your goal? you distance is critical to help design a trainign plan.
Fartlek is a trainign, and racing technique, form- if you want to call it that.
how about you start with running a 8 min pace for 5 min, then walk 2 min, and see how that goes.
go for 5 rounds = 45 minutes or so. Average= 5 mile training run.
p.s. i will not keep on with you on this idea. I am not a fan. I think the walk makes a runner get impatient and they do a skip when they take off, and that can cramp a calf. Secondly, when they run, they know they are going to be walking soo, so they run harder and harder, and then have terrible form as they slow down into a walk, and that is prone to developing shin splints.
IF YOU ARE NOT A MATURE RUNNER, this is probably not the best idea.
it's an old man's technique so catch his breath.
If you use this to train, then believe me, when you go to do a marathon, you will end up walkin for sure, and after mile 18, it is very hard to pick up and run again.
hahahaa-- guess I have some energy about this.
FF