I found this article interesting because, while the article says they're "breaking all the rules," it seems to me they really aren't. They're just delivering the same elements in a different form. Note that his "strides" are 8 x 30 seconds. Thirty seconds is almost 200m, so they're basically doing 8 x 200m six times in a 10-day cycle (plus 3 hill days, 1 long run). That's plenty of speedwork even though he doesn't call it that, and the hills provide strength and speed as well. With that kind of speed frequency, no wonder they don't change much from season to season! The hill runs are basically varied-pace runs, so they're hitting all their zones just like everybody else does, and they're doing a long run as well.