10 miles - finding threshold intensity - 9/1

In addition to trying to figure out my tempo pace (starting off with aiming for a HR of 160 for around 20 minutes the other day), I also want to determine my threshold pace. Daniels defines this pace as that which is a little faster than marathon (ie, can hold for two hours or more) pace, but a little slower than what could be maintained for 30 minutes. With my long distance runs occuring at a HR of about 150, and the tempo runs having been at 160, I figured I'd shoot for about 155-160 and see how things went. I'm paying attention to HR as opposed to pace for a couple reasons - one is that my instantaneous pace as displayed by my HR monitor is way too erratic to follow directly, and the other is that I'm interested in running at a level that will properly apply stress based on intensity of effort as opposed to simply speed.

I have normally been shooting for about 90 minutes during this mid-week runs, and I knew that I am capable of maintaining my target HR of 155 for this amount of time, as I had an average HR of 163 for just about 2 hours during the Worcester half. In fact, if anything, I'm targeting a pace a little lower than what I'm capable of. However, I'm only just starting to try and hone in on these various intensities - and I'd rather undershoot at first than overshoot.

I chose a route that is about 10 miles, knowing that I'd probably end up finishing before the 90 minute timer. But this would give me an opportunity to run a first mile as a warm up, then eight miles at the target intensity, and then a full mile as a cooldown as a recovery HR.

Overall, things went pretty well. It was a little challenging to stick to the 155-160 range - it seemed like any little elevation change made it drop to 153 to shoot up to 162, but like last run, I just adjusted pace accordingly to maintain intensity. Of course that means that during some steeper inclines, the pace dropped to 10 min/miles or slower, but the payoff is that it allowed a faster pace overall while still being comfortable. I felt strong throughout the entire run, but did notice my pace dropping a bit during the last couple miles. Refocusing on cadence seemed to have helped a bit - as I tired my target cadence of 180 slacked a bit. I think the full mile of recovery HR intensity was useful - I'm writing this post the morning after, and even though I took an ice bath after the workout, I do feel some slight soreness/tightness which surely would have been worse without the full mile cooldown.