One of my New Year’s resolutions is to run a 10k race under 55:00. The time was chosen based on my aerobic running program, which includes a weekly jog of one hour during which I cruise along at a speed that keeps my heart rate in its aerobic zone, 160 bpm or less. Around New Year’s this was yielding runs of ~10k on my treadmill so I figured that a 5:00 improvement on that time would be a good goal.
My lifetime record in 10k races is 0-1. When I was a kid (7 or 8, maybe?), one of my mom’s friends was an avid runner. He was going to run in the Huntsville Cotton Row Run (10k) and, for whatever reason, I decided I wanted to run too–despite never having run more than a mile in my life. I started near the back of the pack and steadily lost ground until, after only a mile and a half or so, I could no longer see anyone else ahead of me. I was so winded by that point anyway that I just gave up, sitting on a doorstep until my mom came driving along the race route frantically looking for me. One of the least proud moments of my life.
With my first 10k race of the year coming in March, I decided to do at least a little training for it. In January I ran a practice 10k outdoors at Memorial Park. As usually happens, I ran faster outdoors than on a treadmill even at the same exertion level. I hit 10k at 54:00–so much for New Year’s resolutions being stretch goals! My average heart rate was 155 and my max was 170 for that run; it felt really easy.
This taught me that I probably had significant room for improvement, especially once I was buoyed by my 5k performance January 30th. So in February I ran another 10k practice run and this time I allowed myself a greater exertion level. The cool weather felt great and I cruised along to a 51:33 finish pretty easily. Average heart rate was 165, max was 179.
These practice runs helped my gain a feeling for what level of exertion I could sustain over the duration of a full 10k race. An average heart rate of 165 was very doable so I predicted that ~170 should be my target. This conforms with my estimated anaerobic threshold of 171. Last week I tried a 10k while keeping my heart rate around that level. The result was 47:50, average heart rate 166, max 183 Looking over the data I could see that, after a quick first 5k, my pace slowed significantly in the latter half in order to keep my heart rate around 170. I ran the first 5k in 23:30 and the second in 24:20–despite an intentional pace increase for the final km.
This wouldn’t do at all; I wanted a negative split–a faster second 5k than the first. Furthermore I wanted enough gas in my tank to push hard at the finish. So I ran one last practice run on Sunday–after a brutal legs workout in the gym Saturday. This time my goal was to keep my pace down in the first 5k so as to maintain that same pace throughout the second 5k before kicking it at the end. The goal was a 23:50 first 5k and a 23:10 second 5k–a 4:46 per km pace through 9km then a 4:05 final km.
I came out a little quickly and my first 5k only took 23:42. My heart rate was 160 after 1k, 165 after 2k, and cruising altitude–170–after 3k. However, around the 8km mark my hear rate headed north to 175 and my pace slowed to the 4:51 range. I entered the last km about 10 seconds ahead of pace but, when I turned it up, my pace didn’t increase enough and, when I kicked it for the last 100m, I was basically out of juice. My final km pace was 4:19, finishing in 47:05, just shy of my target. Average heart rate 169, max 184.
Now I have a great idea of where my limits are and where I can/should push them. On race day I will also have the advantage of not having just destroyed the muscles of my legs the day before! For what it’s worth, my 47:05 time would have put me at #284 of 1,500 runners and #29 in my age group of 124 runners–81st and 77th percentiles respectively–at last year’s Bayou City Classic. The year before I would have been #257 of 1500 and #13 of 97 in my age group–83rd and 87th percentiles respectively. These are not as high as my percentiles from the Texas Med 5k, but that is to be expected since this is a distance I’ve only been running for about a year. Also the cold, rainy Texas Med 5k might have attracted fewer serious runners.
With only five days left until the race, it is time to set some goals:
1. Total race time under 47:00
2. Negative split: second 5k faster than first 5k; specifically 23:50 and 23:10 respectively
3. Final km under 4:06
4. Final 400m under 1:15
5. Each km time for the first 9k within +/- 4 seconds of 4:46
I’m hoping I can sustain the 4:46 pace at aerobic levels longer this weekend than last by virtue of rest, nutrition, and hydration throughout the race. Having learned that 1km out is too early for me to kick it, my new race plan is to maintain pace through 9.6km then turn it up for the final 400m. Fresh I can run 400m under 60 seconds so I’m hoping to make it under 75 seconds here.
I’m very excited about this race and looking forward to taking revenge on my nemesis, the 10k, after nearly a quarter century!