1600 Reps?

Damn. I knew 3x1600 @ 5:41 was going to be hard, but I didn't think it would be impossible.

I went 5:42, 5:52 and 5:58—notice a trend? Plus, I did a very slow 400-meter jog between the 1600s instead of the called-for one-minute rest interval.

This workout comes from the FIRST program and is based on a 5K PR of 18:30. No, I haven't run a 5K in 18:30, but I'm pretty sure that if I went out on a flat course this weekend and tried to, I could. I'm sure of that—so why did I fail so miserably at this strange VO2 workout?

Well, let me start by explaining why I call it strange.

FIRST is about the only program that calls for 1600-meter repeats. Matt Fitzgerald talks about "specific endurance intervals," which he defines as 200 meters to 1K. Daniels says that unless you can run 1600 meters in five minutes you should be doing 1200 meters for your long track reps. Pfitzinger's longest VO2 reps are 1200. And even at that, all of these guys are expecting you to use 5K race pace—around 5:57. McMillan is right there: Punching in an 18:30 5K on the calculator yields 5:55.2 to 6:08.3 for 1600 reps in speed workouts.

I guess FIRST, because it's based on doing just three runs a week (plus two cross-training workouts), pushes the intensity to the nth degree. But of course, I'm modifying FIRST to include leisurely and long recovery runs at least twice a week because I just don't have confidence that I can shave 6:17 off my marathon time running 30-35 miles per week. So maybe it's not vital that I nail these weirdly lengthy track reps that nobody else in the running world asks you to do? Hmm. Well, I'll do this workout again, 11 weeks from now—five weeks before the marathon—and when I do I'll have today's pitiful results to look back on for comparison.