Run Pacing

Run pacing is something that I struggle with.  I've been following the Barry P plan from SlowTwitch and recently read Don Fink's book on half ironman training and set my zones up accordingly.

Max HR - 193 (during an all out spring the last 200m of a 10k)

Zone 1: 125 - 143
Zone 2: 144 - 164
Zone 3: 165 - 172
Zone 4: 173 - 183

My half marathon pace from October was 9:55 / mile.

I've been following the Barry P plan for 4 weeks and I'm not sure how quickly you are supposed to notice an improvement, but I've either made some significant strides or my HR monitor is messed up.  Here is an example:

Week 2: 1.5 mile run @ 10:49 pace with average HR of 145
Week 4: 5 mile run @ 10:18 pace with average HR of 137 (it seems crazy that this would be a zone 1 run)

I changed the battery in my HR monitor to see if that makes a difference and should have some idea after today's run.

In the past I've always used perceived exertion to set my pace, which is usually dictated by my legs.  Lately my legs seem to be the limiting factor as I can definitely push the pace while the HR stays lower.  Part of this can be attributed to my legs being tired from the increased workout of swimming, cycling, and running.

I don't know if there's any right or wrong answer, but for now I will try to run based on HR and will channel my inner Jens Voigt when my legs protest (SHUT UP LEGS!).