According to the tables in Daniels' Running Formula, my 5K time suggests my Vdot is 45. Again according to Daniels, this puts my easy pace at 9:17 min/mile, my marathon pace at 7:57 and my threshold pace at 7:25. Since my easy my usual easy morning run has a pace bit over 8:00, this suggests I'm running too fast for now and that I could pretty easily run three miles of threshold pace twice a week. This might make my foot feel better and allow me to do more speed work (if running a 7:25 pace for three miles even counts as speed work). BTW, a Vdot of 45 is associated with a marathon time of 3:28.
Daniels suggests not moving up more than one unit of Vdot every three weeks even if you are getting noticeably better running. Given my age that should probably be not moving up more than one unit of Vdot every six weeks or so. Surprisingly, even a 5K time of 21:02 only gets you to a Vdot of 47, which corresponds to an easy pace of 8:58, and a 5K time of 19:57 (my aspirational time) gets you only to a Vdot of 50, which corresponds to an easy pace of 8:32, still faster slower than what I usually run. The threshold pace for a Vdot of 50 is 6:51, marathon pace is 7:17.
This suggests I should cut back on my daily speed and go for some very unambitious threshold running over three miles a couple of times a week (i.e. push myself much less than I did when I took out my foot). I could give it a try.
There are claims out there that training above the Vdot paces suggested by race performance raises injury risk significantly enough that you don't want to do it...not sure about this, but since I am having foot problems I should probably consider taking back my pace and concentrating on a few miles of higher speed running each week.
Back to my motto from last fall: use all my discipline to run slowly!
Update #1 (May 12): ran a 9:12 pace for 30 min this morning, then intervals for 10 min. The Vdot 45 target easy pace is 9:17, so I pretty much hit it. There is no way I'm going to get injured at this pace, it feels as easy as walking and there is very little foot impact. This should pace should let me run five or six times a week without any injury issues. That should, hopefully, let get my feet toughened up and allow me eventually increase my pace -- as well as run the threshold pace of 7:25 twice a week.
I also calibrated the foot pod, it seemed to be overstating my distance/speed by 5% (which I sort of suspected -- I should run a track some weekend and see if I get the same calibration factor as I got off the 5K race).
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