Today's work out will be the warm up, 45 minutes run/walk at 4:1 ratio. You will run approximately 22.5 minutes out and back. On your second half, add 30 seconds surge but continue to use walk break. A surges is a gradual increase in pace but not a sprint. The final 5 minutes of the work out is to cool down after your run.
If you have any question please ask me .