Getting back into intervals

When I was training for my second half marathon, I did 400-meter repeats, because that's what Hal Higdon told me to do.

I didn't have a smartphone then, so I picked a spot based on easy measurements rather than on optimal terrain. Nor did I have a clear idea of interval pace versus recovery pace. Going slightly downhill at top speed could be fun, but that wore off quickly after just a few recovery jogs up a long, slow incline.

When I was training for my third half marathon, I reluctantly returned to repeats — but I sure wasn't diligent about them.

However, I had a smartphone by then, which meant I could just start wherever a certain traffic-free rural road became mostly flat and run until MapMyRun told me to stop. The plan wasn't perfect: There was still a slight drop and an oh-so-helpful tailwind as I sprinted; there was still a slight incline and frustrating headwind as I recovered.

Plus, I still went too fast, but at least this time — having read that if you have to stop and gasp for breath, you're going too hard — I was aware of the problem. (But not quite able to stop it.)

Now, I'm not training for anything in particular, which I realized yesterday morning is not optimal. But with evidence of potential improvement in my 5K PR, I decided that it was time to raise the bar a little bit and sought help from Twitter.

Brad of On the bus ... Running answered: 400-meter repeats. More importantly, he recommended using the McMillan Running Calculator to determine what my times should be. I'm sure I've read/heard about the calculator before but just forgotten. Kind of like how I knew intervals were helpful for improving, but "forgot."

Anyway, yesterday's intervals went as follows: 2:02, 2:00, 2:00, 1:58, 2:00, 2:02.

I gave myself major pats on the back for the following: consistency, rather than flying and crashing; proper route choice, with no hills either way and all gusts coming during recovery jogs; mostly continued movement, even after the sprints.

As for the McMillan suggestions? I came up a little fast if I'm treating this as a stamina workout (2:06 to 2:10), a little slow if I'm treating it as a speed workout (1:49.5 to 1:55.5 for speedsters, 1:50.9 to 1:57.8 for endurance monsters).

So I'm a little off, but I'm very much encouraged. At no point did I consider keeling over, which was a frequent problem in past interval sessions; it's just that next time, I might consider being a little bit less comfortable.

Is it improved fitness, improved weather or improved feel for pacing that got me through? I'd like to think it's a mix of all three (because I can't deny that this fall has been better for running than last spring).