Wayne’s World

21 10 2008

Running by the Numbers: My Denver Half-Marathon Report

I came up with the following plan for the Denver Half-Marathon: Try to keep close to an 8-minute pace, but keep my heart rate at 162 beats per minute or below for the first 10 miles, then try to pick it up. An 8:00 minute pace would result in a race time of 1:44:52, about a minute better than my previous PR of 1:45:55 at last year’s Boulder Half-Marathon. This was a challenging goal, but it seemed reasonable, since I felt that I was in about as good shape as last year, and since the Denver course looked to be faster than Boulder’s. I have found that if I let my heart rate go too high in the first half of the race, I am likely to slow down in the last few miles.

I used a Nike watch to manually keep track of the mile splits. I also used a Polar RS200SD watch, which was linked to a footpod accelerometer sensor and heart rate sensor. I set it to autolap, so it would keep track of the average pace and heart rate for each mile. Since I missed a couple of the mile markers, this enabled me to estimate the missing data for those splits. After the race, this gave me plenty of information to analyze. During the race, I could get a sense of how close I was to my planned pace. I used the heart rate monitor to keep myself from going too fast.

Here is the record of the mile splits and heart rate:

Mile Time Heart rate

1 8:12 145

2 8:01 154

3 7:43 160

4 8:00 163

5 8:00 165

6 7:59 163

7 8:02 162

8 8:03 162

9 8:10 165

10 8:22 168

11 8:03 167

12 8:04 168

13 7:56 169

13.1 0:54 172

Total time: 1:45:23

Overall average pace: 8:02

Overall average heart rate: 162

Maximum heart rate: 174

Pace for the final 0.2 miles: 7:38

I was able to keep pretty close to the plan. I went a bit fast on mile 3, but when I saw my heart rate going up in the next mile, I knew to hold back a bit. My heart rate sometimes went above 162 in the first part of the race, but not by too much or for too long. Mile 10 had the worst hill, I lost about 20 seconds, and my heart rate went up. After that hill, I worked a bit harder, knowing I had just 5 K to go. My heart rate went up to the high 160s, and I was able to keep my pace up and even increase it a bit. One of my goals was to finish strong, and I was able to do this, unlike in many of my previous half marathons. It was a PR by 32 seconds.

Contrast this to the 2007 Boulder Half-Marathon:

Mile Time Heart rate

1 8:20 152

2 7:45 160

3 8:03 162

4 7:52 164

5 8:11 165

6 8:07 167

7 7:43 167

8 7:38 164

9 7:59 164

10 7:40 165

11 8:39 164

12 8:34 166

13 8:34 167

13.1 0:48

Total time: 1:45:55

Overall average pace: 8:05

Overall average heart rate: 164

Maximum heart rate: 170

After mile 3, my heart rate went well above 162. Especially note the 167 heart rate for miles 6 and 7. After keeping an average pace of about 8:00 for the first 10 miles, I slowed down significantly in the last 3 miles: 8:39, 8:34, 8:34. Although this was a PR, I probably could have done better by holding back a little in the first 10 miles and not having to slow down so much at the end. It might be that 163 is OK, but 167 is definitely risky.

I think I have come up with a fairly optimal strategy for myself for a half-marathon. Depending on the difficulty of the course, my ideal pace will vary, but I think the ideal heart rate will be about the same (162-163 or below).

Looking back at my previous full marathons, I suspect that I should try to keep my heart rate at 149 or below for the first 20 miles to keep from fading at the end. I’ll test this plan when I do the California International Marathon in Sacramento this December 7.

Wayne Itano October 20, 2008




3 responses

21 10 2008
Curt Culver

Hey Wayne,

Congratulations on a great race and another pr.
I had you in my sights most of the way after you had past me.
I lost my 8:00 min mile pace about the same time you did but fell off farther than I wanted and could not regain the lost time I had hoped to on the last 3 miles. But it was a pr for me also by over 2 and half min.
I enjoyed the day but the pounding of the pavement took a toll on my body. I need some recover time for sure.
Good luck at CIM


21 10 2008

Congrats dad!! This is great news and I’m so impressed… another PR! Can’t wait to see you out here on the OBX. I’m sure it’ll be boring in comparison… but hopefully nice on your legs. Bring your data, or send it… and we can look over it in a few weeks together!
Love you!

21 10 2008
Wayne Itano

Congrats on a big PR! I’m back to training for the marathon. 3.5 miles VERY easy yesterday. 2 x 20 minutes lower zone 2 today. Looking forward to taking it easy after the full in December.

I’ll be using the Outer Banks Half to collect some more data on heart rate versus pace on a sea level course. It should help me set a goal time for the CIM.


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