Sunday, November 15, 2009

Battling My 10K Demon

I've blogged about this many times before: the 10K is my weakest distance. I think I finally have a physiological explanation why. It doesn't make sense that I can run a half marathon at about the same pace as a 10K, but maybe it's starting to make sense.

I ran the Veteran's Day 10K today. It was in the low 50's and sunny and the course was flat. These are arguably perfect racing conditions, although I would have preferred more cloud cover. I had run this course twice before-- in Oct. 2008 and Dec. 2007. My PR was set on this course in Dec. 2007 at 49:23. Since then, I had run many 10Ks that were pretty much equivalent to that, despite my fitness getting remarkably better over the past two years.

I decided that no matter what, I needed to get a PR today. I have had six weeks of training since my injury so I had no idea what kind of shape I was in. But even though I am not where I was pre-injury, there is no reason why I shouldn't have been able to break that soft PR. My strategy was to start out at a pace of 7:50 and then gradually speed up if I felt that I could. I was aiming for a PR by about 45 seconds, although I knew I was capable of faster based on some recent training runs.

Mile 1: 7:46
Mile 2: 7:48

These miles felt easy. I could hardly believe I was going at this pace for how easy it felt. I was afraid to run faster, though, and I told myself I would really hammer it home on the second half if I continued to feel this good. During the first mile, my boyfriend ran ahead of me. This surprised me because his goal was to run a 7:45 pace, but he ran ahead at what must have been a 7:30 pace.

Mile 3: 7:52 (includes water station)
Mile 4: 7:48

It started to feel difficult and I kept looking down at my HR monitor wondering why my heart rate kept reading 181. It should have been reading 184-185. I knew I wasn't putting forth a true race effort based on my heart rate, but it felt really difficult and I decided that I would save it for the last mile because I didn't want to push too hard too soon.

Mile 5: 7:55
Mile 6: 7:57

I gave it everything I had during the last mile, but all I could muster was a 7:57. I just didn't have the energy to push any harder. I wanted so badly to get a 10K time that reflected my true abilities, but it just wasn't happening. I looked down at my Garmin as I saw the finish line. I had to make it there under 49:00. I dug as deep as I could and found a 7:22 pace for the last 0.2 and my heart rate finally got up to 184, which is where it should have been for the entire race.

My average heart rate for this race was 180. It should have been about 185. I ran the entire race in my "lactate threshold zone" which is considered your 15K or 10-mile pace. I got a great tempo workout in but I didn't actually "race" this 10K. It wasn't like I didn't try. . . I just didn't have the energy to get up where I needed to be. I keep asking myself if I had run the race based on HR and not on pace if I would have fared much better, but I am just not sure I could have actually maintained a 185. I wouldn't be surprised if I maintained a similar heart rate for my upcoming half marathon.

This is something I am going to ask my coach about: why can't I find the energy to get my heart rate (and speed) up to where it should physiologically be for a 10K? I can get my HR where it needs to be for all other distances-- even the 5K! But for some reason, this 10K just kills me every time.

I am happy that I set a PR, and I feel like I ran it as hard as possible. The evidence being that I faded during the last two miles. Maybe next time I go out at a pace of 7:35 and fade down to a 7:50. Establish that I am going to be at a higher heart rate early on and just stick it out. My boyfriend ran a 46:56, which is a four-minute PR.

Finish time was 48:54, a PR by 29 seconds.

I placed 19 out of 205 in my age group. This is the top 9th percentile, whereas I usually find myself in the top 5th percentile for other distances.

Up next: Turkey Trot 5K. Goal is 23:10.


  1. Congrats on the PR!

    The HR thing could just be due to the fact that you're still coming back from injury. You kept yourself aerobically fit, but lost specific muscle fitness that you haven't fully regained yet.

    Thus, your lungs and heart could have supported a much harder pace, but your legs couldn't hold up their end of the deal. Your legs couldn't sustain the pace that would have pushed your HR up into the range you wanted it to be.

    So, you've got your work cut out for you!


  2. Awesome that you got a PR! Keep at it, you will get better. I can understand though about a weak distance, I feel the marathon is my weakest. It seems no matter what I do, something always happens... Just keep racing those 10Ks!

  3. Great job, E! I'm so happy you set a PR today! You're definitely back from the injury.

  4. Hey, congrats on the PR! That is something to be proud of!I agree that it is a tough distance.

  5. Cristina, Thanks for your input. That is interesting. I felt like my legs probably could have gone faster but it was a lack of overall energy. My coach suggested that I lost a lot of my "sharpness" during the injury and the ability to stay at higher heart rates for an extended period of time. She said that heart rate zones can change over time, so maybe mine changed and maybe I was running in the proper "zone".

  6. WTG on the PR! I think that's a great race as you work back to a full 100% after the time'll just chip away at it more as your legs get stronger. Nicely done.

  7. I like reading your blog (Hi!). I think you did really well considering all the other factors you have dealt with in the past few weeks.

    Funny, I am the same but opposite of you--I wish my marathon would reflect my 5-10k ability.

    Keep up the good work, I know you can do it!

  8. Great job on the PR! I hope this big improvement in time sours your confidence in marathon training- it should. YOu did great out there! FWIW, what you talked about it is the reason I don't wear a HRM.