I haven't run a timed 5K in quite awhile. I'd have to go through my notes to see when I last did one, but I'm pretty sure I haven't done it yet this year. I don't think I've done a mile-and-a-half "Navy PRT" test in many months either.
I did it this morning, following the scheduled plan for a little speed training. My schedule was disrupted yesterday when I had hoped to do an 8-miler out-and-back during lunch but was overcome by events at work. I wound up knocking out an easy paced 45-minute session on the treadmill to get some mileage in before the commute home to meet the family for dinner at Stir Fresh. I'm just about 2-3 miles behind the weekly mileage plan now.
I wanted today to be more strenuous and I wanted to see if all the endurance training I'd been doing has had any effect on my anaerobic capacity.
My 1.5 mile split disappointed me even though it was a decent time. I felt like I was really pumping and was hoping to better my old previous best from August of 9:44. I hit the mark in 10-minutes flat. I was surprised to feel like I had plenty of reserve at that point and knew I could have kicked it up a notch. But I had started out conservatively, worried about burning out too soon. 10 minutes over a mile and a half is a 6:40 mile. To get my time down to the 9:30 target, I'm going to have to be able to sustain a 6:20 per mile pace. I don't think that's as impossible as I once thought.
The disappointment of not breaking 10 minutes at the split must have goaded me, because I wound up with a 21:23 5K time. Unless I'm forgetting another better outing, this was an improvement by 24 seconds over my previous best of 21:47. That's kind of a big jump. I think I can bite into that by another 23 seconds and bust that 21-minute barrier.
I sheepishly adjusted my 5K time goal for the year from 20 to 21 minutes when I started to believe that maybe 20 minutes was just too unrealistic. I'm not so sure about that now. I didn't really enter into the "pain cave" on this run today, so to finish with that kind of time means I could press a little more and maybe knock off those next 20-25 seconds. Just doing it on the 1.5mi split would be good.
I'm very encouraged.
I pushed my peak HR up to 95% and held an average near my 90% range, but I was breathing steady and strong and my legs felt great. After all this time, I'm still not clear on what is supposed to change with respect to heart rate as I get more fit and conditioned. I've been estimating my HRmax to be around 175. I'm more comfortable than I used to be when I get up into the 158-163 range, which is where I think I'm crossing the threshold from aerobic to anaerobic. I think the reality is that my HRmax is fixed no matter what I do, but that lactate/anaerobic threshold must be what varies as my heart and lungs get stronger. Whereas 85-90% of max might have once been fatiguing, now I think I can sustain 90-95% of max more readily.
I suppose there's a ceiling there.
But overall, good workout and even though my focus is endurance, I think I can simultaneously work to whittle down my 5K time to 21 minutes by the Carlsbad 5000, and maybe reach that 9:30 mile-and-half boundary too.
