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Predicting Your Boston Time

With just two weeks to go to Boston, I wonder a little just what time and pace I should target. The answer probably lies in a multitude of factors. But perhaps the most basic is simply recent race performances. Isn’t this why we run “tune-up” races in the first place?

Using an online pace chart tool such as a Pace Wizard makes it easy to convert recent race times into predicted times for other distances including the marathon. This tool is very helpful to know what you are CAPABLE of doing when everything comes together perfectly for you – the right weather, adequate training, nutrition, race course topography, etc. So before you get really chuffed about your predicted Boston time, best remember what kind of race course and day your reference race was, and other basics. Do you expect the same conditions at Boston? Are you in better or worse shape since your reference race? ETC!

This is my first Boston. However, I have heard again and again that it can be cruel. Gamble too much in the first half, or get caught up in the early pace (the first miles are really downhill), and you will pay dearly in the second half. That written, if you have inserted copious amounts of hill training into your work up to Boston, and you own an efficient downhill stride, then maybe better results are possible. Just look at what the top five in my chart (see bottom) did to Boston! Please note all these people are serious runners training over 100k/week (some over 150k) and they were also some of the top Canadian finishers at Boston 2011.

But which race to use? Your winter half or ATB? Is one result better than the other for predicting your Boston time? To answer this, I did a bit of research on 2011 race results.

Many Boston runners use an early spring half (Peterborough or Grimsby) and the ATB as tune-ups. I have picked a small sample of better runners to compare from available results. All times were converted to equivalent marathon times using the Pace Wizard, and summarized in the chart below. But please understand there is only sufficient data here to discuss ideas, not enough to confidently predict outcomes with any certainty. There are just too many factors that influence race performances.

So what does that chart say? In my opinion, ATB is not a very good predictor. Perhaps some are not giving this race their best; while others have given too much to ATB and have nothing left for Boston. However if you are strong and have an athletic body type that can absorb the beating Boston gives, then maybe better can be expected.

Again, in my opinion, it would appear that the early half marathon predicts a result closer to Boston expectations for most good runners. These half marathons are usually taken 6 to 8 weeks out from Boston. This means there is sufficient time for recovery, and most runners will sacrifice a bit to ensure a good result. Also, in most cases, these runners are still improving their performance in terms of endurance, stamina and efficiency. By the time Boston arrives they will be in better shape.

So what is your race plan for Boston? Well that depends specifically on you. Have you trained deliberately for Boston (hills, hills, hills)? If so, you might want to aim a bit better than your pace chart, by a couple of minutes. In most cases though, you would be wise to go out and stay on pace (especially in the first half) to what is predicted by your best race result (half or ATB).

Let’s see how I do! My half predicts 2:54:00 and my ATB predicts 2:52:30. I am aiming to repeat my BQ time of 2:50:50. I have trained hills and more hills. Game on.

2011 Half, ATB and Boston Results


Born and raised in Hamilton & Stoney Creek. Ran X-Country in high school, but not really special at it - a middle of the pack finisher. But then again, really didn't know how to train. Didn't run after Gr 12 due to nasty shin splints. Really never ran in proper shoes back then. Didn't try to run again until age 30. Then tried. And tried. And tried. Shin splints every time. Finally got it going for good at 38 in proper shoes and I have vowed never, ever, to stop running again.

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  • Your Pace Wizard predicted my Boston time from last year perfectly based on my Peterborough half race. I was in better shape for Boston but it is definitely a tough course. The last downhill section is killer. If pace bands interest you, the Nike Store has bands for the course. Good luck.

  • Thanks Erin! 4:00/k is my goal pace right up to 30k, then I will evaluate from there. Fortunately I have run the last half twice and know what to expect. The last half is a total blast on fresh legs, but could be hell on burnt out quads. The key is keeping the first half very very real.

  • Daniel,

    It looks like your Pace Wizard missed the fudge factor of running in 33C temperatures. Everyone I know who ran Boston this year ended up giving up on their goals for finishing at a certain time. Sometimes the heat wins out! This tool does help most of the times.

  • Aaron and everyone else who have just read this, this article deserves clarification. Even without the heat, Boston is way harder on you than any race around the GTA. Unless you have gotten way better since your BQ race, attempting your BQ time at Boston may be a big mistake.

    Sure use a pace wizard to predict your potential time, but please do make the necessary adjustments to ensure your Boston expectations are realistic.

    If you don’t you will pay, just like I did.

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