I want to get into 16:45 shape, but I have done nothing, but 6 mile runs since last summer. Is 8xs 1/4 on the treadmill at a 5:50 pace with a minute rest, a good starting point. I might try and this Thursday. 5:40 pace feels pretty easy. Then I will work it down each week and add volume. I have done some 200s and stuff, at a faster pace so it should be easy.