I boarded a plane and headed to Boston. It was my annual pilgrimage to the Boston Marathon. I had 252 McMillan athletes running and was excited to get to town, meet up with them and put the finishing touches on all the prep they’d done for the big day.

As always, expectations were high. Everyone wants to run well in Boston and many rely on running fast so they re-qualify for the next year. Plus, the city, the crowds, the history and the buzz at marathon time just make you want to put your best foot forward. That’s the magic of the Boston Marathon.

Factors for Boston Success

Boston is unique in that it has four variables that lead to success on race day. First, the course can be punishing if a runner is not properly prepared for Boston’s relentless downhills. If you do your prep right, you can run very, very fast at Boston. Second, the crowds are exceptional. They are thick and vocal. They recognize when you’re running well and let you know. And when you’re not running well? Get ready because they are not going to let you stop. They root for you, and when they see you respond, they go crazy. It’s amazing (and much appreciated).

Third, Boston is the most competitively deep marathon most of us will ever run. The entire route, you are literally surrounded by hundreds of runners who are running at your pace. Most marathons spread out. Not Boston. It’s thick from start to finish so you always have someone running your pace to help you and provide motivation.

Fourth, and this is the biggie, Boston’s weather is variable, to put it mildly. While you can count on the Boston course being a unique challenge and you can bank on the crowds and people to race with, it’s the weather that is always the big wild card. Since the course is point to point (West to East), you not only have temperature to consider but you have wind direction to worry about as well. Get a cool day with a tailwind and you will see extremely fast times like we did a few years ago. Get a hot day with a headwind and it’s a totally different marathon.

In 2016, the weather bug bit again. All week, the weather (which coaches and runners were constantly watching) seemed to be improving. From starting out looking very hot on race day to getting cooler and cooler as Patriot’s Day arrived, it seemed like we’d avoid the heat and have a fine day for running. Even on race day in downtown Boston, where I was stationed to cheer runners home, it was good running weather.

As we learn again and again with the Boston Marathon, the weather from town to town along the course can be very different. This year was no exception. While it

was cool at start time in Boston, it was sunny and getting hot in Hopkinton. It wasn’t the heat fest of 2012. Instead, it was a sneaky hot day, and the results showed with most runners running well off their goal pace.

Crunching the Numbers

As we always do, I returned home from the trip and my fellow McMillan coaches and I started to crunch some numbers. When athletes run slow, they need to know why. We start with the following viewpoint: If everyone in the race runs slowly, then it’s just the day. If you’re the only slow one, then it’s time to dissect your training. For Boston 2016, it was the day. But just how slow was it for folks? I needed to know so I could help athletes understand whether their “bad” day was actually a good day, given the conditions.

From my research, I found that results varied depending which group of runners you were in. I don’t mean wave or corral. I mean in terms of your preparation and race strategy. Here’s what I found:

Group 1
Group 1 was a happy but lonely place to be. This group included runners who ran better than or very near (<2% slower than) their goal time, even on a hot day. There weren’t many in this group but they certainly had exceptional races. Most, it seemed, were poised for a big breakthrough anyway so maybe their goal time was conservative to begin with. No matter what the conditions, they were ready to run very, very well.

Group 2
Group 2 included runners who were well prepared for Boston and reasonable in their intended goal pace. These savvy runners, recognized before the race even started that it would be hot and dialed their pace back some. Of the runners who slowed, they seemed to have suffered less than Groups 3 and 4, below. They seemed to average ~2-4% slower than goal pace.

Group 3
Group 3 included runners who were well prepared for Boston, reasonable in their intended goal pace AND they recognized in the early miles that it was going to be a hot one. As a result, they dialed back their pace in the first 5-10K of the race. Group 3 ran ~4-6% slower than goal pace in the race and the last 10K was still very tough for them.

Group 4
Group 4 included runners who were well prepared for Boston and reasonable in their intended goal pace. BUT, they didn’t adjust based on the weather. They ran the race as if it was perfect running conditions and not on the hot side. In this group, I found two subgroups:

Group 4 runners who are good heat runners and/or acclimated to hot conditions ran ~6-8% slower than their goal pace.

Group 4 runners who are not good in the heat and/or weren’t acclimated (i.e., a runner who was training in cold conditions all winter) ran ~8-12% slower.

It was a very tough day for those in Group 4 who were not heat acclimated and many fell apart well before the Newton hills.

As you evaluate your Boston performance, think about which group might be yours. Then, take the percentages the research showed and apply it to your Boston time. If you were within or better than the new Boston 2016 “adjusted time” then pat yourself on the back. It’s not always about the finish time. It’s about how you ran on the day. Hopefully, this analysis helps runners evaluate their races and get a better picture of their actual performance.

Why So Slow?

A collection of factors came together on race day to make this Boston Marathon feel hotter than it seemed like it should have. First, the temperature was warmer than ideal. The temperature graphs on race day show that. Second, there was wind. Now normally the wind, which wasn’t extremely strong, would help with cooling. Although, it also has the effect of evaporating the sweat quickly so you don’t feel like you are sweating a lot. In fact at the finish line, runners weren’t soaked like in 2012. They seemed normally sweaty but reported feeling quite hot on the course. Could it be that folks were getting more dehydrated than they knew?

Third, we didn’t respect the potential heat as much as we should have. In years past, there was much talk about improved hydration, but many runners stated that it wasn’t until later in the race that they really started to drink more and by then it seemed too late. Lastly, there was no escape from the draining rays of the sun from standing around in the starting village to running the entire route.

What Do We Learn?

As a coach, how do I talk some disappointed Boston runners back from the edge? First, look at the adjustments above and use them to evaluate whether your time was really “bad” or not for that particular day. Second, Boston is Boston. Talk with veterans of many Boston Marathons, and you quickly see their wisdom. They just take the day for what it gives. They don’t beat themselves up. Sure they may wish they had run faster but they just seem to take unfavorable conditions in stride.

Next, remember to watch the weather for each town along the course. If there is any suggestion of poor conditions, dial up Hopkinton all the way to downtown Boston and see what’s predicted in each town. And if the conditions look challenging, then

adjust your goal ahead of time (like Group 3). While you may run slower, it definitely makes it a more pleasant race experience than if you don’t adjust.

We also learn that it’s important to acclimate for every Boston. You never know when it’s going to be hot. Since many runners are training in cool conditions, make sure you are getting some hot runs in. Wear extra clothes and run inside in reasonably hot conditions. A few “hot” runs can help your body be better prepared for a hot marathon. Remember, a well thought out hydration plan for the race is key.

Lastly, celebrate. It’s Boston! It’s a dream for most runners to qualify, and you did it. As folks say, “A bad day at the Boston Marathon is still a great day of running.” I’ll raise a glass to that. See you next year Boston!

FREE Marathon Recovery Plan

After Boston, you’ll want to recovery properly but also not lose all your fitness. To help, I put together a marathon recovery plan. It’s free and will give you the recovery you need but help you hold onto your fitness so you’ll be ready for your next training plan.

Written By Greg McMillan
Called “one of the best and smartest distance running coaches in America” by Runner’s World’s Amby Burfoot, Greg McMillan is renowned for his ability to combine the science of endurance performance with the art of real-world coaching. While getting his graduate degree in Exercise Science he created the ever-popular McMillan Running Calculator – called “The Best Running Calculator” by Outside Magazine. A National Champion runner himself, Greg coaches runners from beginners to Boston Qualifiers (15,000+ and counting!) to Olympians.

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“I got my first Boston Qualifier today with a 21 personal record!”

– Ramona M.