Hey Wisco Boy.
I'm the one who posted the workout of 1-3-1-3-1. The workout was Elena meyer's top female Marathoner in the world years ago, shes said she uses that sort of training while training for the 1/2- Marathon.
The workout goes 1mi at 5k pace, 3mi at MP, 1mi at 5k-10k pace,3 at MP and 1mi at 5k-10k pace. The 1 miles rest is 3-4 minutes and the 3miles is 4-5 minutes.
I'm running it tonight as my workout, so it outta be a tough by very good workout,as it mixes speed with endurance.
Goodluck!