BGW == before gallo walking.
What are you training for? Galloway's BGW 1.0 1984 book's programs are tough, IMO, despite being lower mileage. 13x1miles for the marathon at pace, book-ended by a 26 full distance long run a week or two before? A 26 mile training long run is tough when doing those intervals every other week. For some time goals, he has you going 28 or 30 miles too if I remember correctly. I'll have to dig it up.
Just training for the 10k? There's a nice 20x400 workout for that time goal! I tried it once but only made it to 18x400. 18x400 was enough to get my time so maybe 20x400 is unnecessary.