One of my non-marathon running friends recently asked about “hitting the wall” in the marathon wondering if it’s a real thing. (Where you feel the sudden onset of fatigue.) I told him that unfortunately, it is very real. I’ve spent time strategizing the best ways to avoid this from happening, and want to share it with all of you. Because hitting the wall is not fun! So let’s find out why hitting the wall in a marathon happens and what steps to take to prevent it.
Hitting the wall in the marathon happens because the body can only store 2,000 calories of glycogen (the fuel you use to run) which is usually used within 20 miles. Being that the marathon is 26.2 miles long, for 6+ miles your body has to use fat for fuel which is a much less efficient process.
Luckily there are ways to train your body to push through the “wall” or even so you never feel it at all. Here you’ll learn more about what hitting the wall (also known as bonking) in a marathon feels like, why it happens, and this good stuff:
8 tips to implement to avoid hitting the wall from happening including:
- Run higher mileage in training.
- Incorporate at least 3 long runs of 20+ miles during your training.
- Put medium-long runs into your training.
- Try running “carb-free” on your easy runs.
- Practice your mental game.
- Carbo-load before your marathon.
- Don’t go out too fast.
- Follow a proper fueling/hydration strategy during the marathon that includes carbs.
Hitting the wall can be overcome!
Hitting the Wall in a Marathon: Symptoms and What it Feels Like
Though you can certainly feel exhausted in lots of sports or after a hard workout, it’s not the same as the wall that endurance athletes refer to. So it’s not to be confused with being tired and it isn’t something you’re most likely going to experience in shorter races. It COULD happen in a long training run, but isn’t likely to happen for most people in the 16 and below mileage range.
So, if it’s not just about getting tired when you run, what does hitting the wall feel like exactly?
Here’s how you know you’ve “hit the wall” or “bonked” in your race or long run:
- You’re in the 18-22 mile range
- You’ve been feeling good or great up until that point and suddenly you don’t anymore.
- You have a strong urge to walk
- a feeling of “dead legs”
- dizziness
- Negative thoughts and doubt creep in
- Both your mind and your body want to quit
- You feel completely depleted (and that’s because you are! Read on…)
This is different from being ready to quit after an intense speed session when you feel like your heart might explode. Rather, this is a pace you’ve been able to carry for maybe 20 miles or more when, with almost no warning, you feel like you can’t run anymore. And it sucks. Yet, it’s completely normal.
Why Marathon Runners Hit the Wall
Though “the wall” or “bonking” are just coined terms for this feeling, there’s actually a scientific reason behind it all.
Fortunately, it’s actually pretty easy to understand.
Your body needs energy and for most people that comes from tapping into glycogen stores. It’s essentially our fuel reserve found in our liver and muscles. Your body can also metabolize fat, but unless you’ve trained your body to do this, it’s a much slower process than using glycogen stores.
The problem is that, in general, a body can only hold about 2,000 calories worth of glycogen. Perfectly fine in everyday life, not so much for a marathon runner. Once that glycogen’s used up, your body has to start the much less efficient process of burning fat. This quick math shows where the problem lies:
2,000 calories stored up divided by (an average of) 100 calories burned per mile = hitting the wall at mile 20
If only our body stored 2,620 calories that would be so much better, right?! Darn. And some people store closer to 1,800 or so, making the bonk come that much sooner.
So many people wonder what the hardest mile of a marathon is, which I discuss in this article, and for most, it’s wherever hitting the wall decides to show up. But does it show up for everyone, or is there a way to avoid it?
Is it Possible to Avoid Hitting the Wall in a Marathon?
As a marathon runner, if you’ve ever hit the wall, then you’re in good company. According to this study of over 300 marathon runners, 43% of them reported common symptoms of hitting the wall. But common or not, it’s an encounter we’d prefer to skip if at all possible.
Top 8 Tips to Avoid Hitting the Wall in a Marathon
- Run higher mileage in training. Being able to run farther, longer, and faster is the name of the game when it comes to marathons. High mileage is a large contributing factor in how well your body can maintain your goal pace for the duration of the marathon since its purpose is to build your body’s aerobic engine. Getting in goal pace miles is important, but note that optimal long-run pace is generally about 55 – 75% of your 5k pace (as stated by Coach Jeff here on Runners Connect.)I love using the Mcmillan calculator to figure out what paces I should be running, by the way!
- Incorporate at least 3 long runs of 20+ miles during your training. The long run is probably the single best indicator of how you’ll fare in your marathon. That’s not to say that quality workouts and the rest of the mileage through your week isn’t important, but safely building those long runs week to week is what really prepares you for the main event of 26.2 miles. Though long runs should be run at much slower pace, these 20+ miler runs are like a dress rehearsal.
- Put medium-long runs into your training. I just started a new marathon training group, and my coach has a medium-long run planned each week. This will be new for me and I can’t wait to see how it helps! Even Greg Mcmillan of McMillan Running agrees that the mid-long run is an important part of building resistance against hitting the wall.
- Try running “carb-free” on your easy runs. Training without consuming carbs before or during an easy run will help your body adapt to utilizing more fat for fuel. I personally would never try this on a quality/speed workout or long run, but I do it pretty often for those easy runs of 7 miles or less.
- Practice your mental game. Yes, the physiological component of hitting the wall comes from a depletion of glycogen in your body. But, you CAN overcome it with sheer will and grit. Remember that your mind will try to give up long before your body actually would need to. The trick is to learn how to just.keep.going. Practice your positive mental strategies in your long runs and these will pay dividends in your marathon. Promise.
- Carbo-load before your marathon. You should be getting as much glycogen stored in your body (without overdoing it) in the week before your marathon. This is not the time to feel guilty about consuming those extra carbs! Your body will rely on it more than you can know. Need more info about how to go about the carbo-load? Read: The Carbo-Load: Why do marathon runners do this?
- Don’t go out too fast. This is one of the top mistakes of new marathon runners. It’s even tough to do when you know better – I’ve been there and it’s hard to pull the reigns in when you feel so good. But this will matter big time later in your race. Don’t go any faster than your goal pace in the beginning, and staying on the conservative side for the first 10k or more is a smart racing strategy. “Banking time” won’t be your friend, and you can read more about that here.
- Follow a proper fueling/hydration strategy during the marathon that includes carbs. A simple electrolyte isn’t going to cut it. You have to make sure you’re ingesting approximately 30 – 60 grams of carbohydrates every 45 minutes to 1 hour in a marathon. This can come in the form of gels, liquids, or solids – depending on what you prefer. But it needs to be easily digestible, so be sure you practice your fueling strategy during long runs before the big day. My go-to is the Sword Endurance drink. And start this early on in your marathon – do not wait!
Ultimately, there will be times when you hit the wall even when you’ve tried to do everything you could to keep it from showing up. Here’s the thing – just because it rears its ugly head, doesn’t mean you have to succumb to it. And a lot of that comes from how you choose to mentally cope with it.
In this Runner’s World Q & A with sports scientist Tim Noakes, he states that he believes the brain directs exercise performance as a way to save ourselves from overexertion by strenuous exercise. What this means is that though you may feel like you’re going to die, you’re actually not. You have to train your brain to be able to overcome the physical pain that comes with hitting the wall. You can go so much farther than you could ever imagine.
So what should you do if you’ve hit the wall? Is it possible to push through?
Unless you’re feeling dizzy or disoriented (in which case you’ll want to assess if you’re in danger with a possible visit the medic tent), you can absolutely get through bonking.
The best thing to do at this point is distract yourself in any way that you can and stay positive. Tap into your mental training that you utilized during all of your long runs. I highly recommend choosing a mantra or two you can run through your head over and over when the going gets tough. “The body achieves what the mind believes,” was mine in my last race. I probably said it to myself at least 100 times. It works!
And if you have to slow the pace down, then do so! But if you never intended to walk in your marathon, I would strongly urge you to just keep running for as long as you possibly are able.
If you’re a running skeptic, there’s a chance you look at Nike’s Vaporfly 4% shoes with some suspicion. In early tests, research has shown that these shoes can improve running economy by 4 percent, but the $250 shoes continue to be put to the test in labs to find out how they make runners more efficient and faster.
And ever since the 4% shoes made their debut for Nike’s Breaking2 project, runners have wondered whether they are only made to help the likes of Eliud Kipchoge set world records, or if they can help the average Joe for every type of pace.
So for all the skeptics out there, here is a look at what we already know about the biomechanics of the Vaporfly 4% shoes, along with the latest answers to your most burning questions.
The early evidence
One of the first studies that looked at the Vaporfly 4% was done in 2017 and published by the journal Sports Medicine. In the study, every one of the 18 runners tested at the University of Colorado Boulder’s “Locomotion Lab” had better running economy in the Vaporflys than when they ran in two other racing shoe models (Nike Zoom Streak 6 and Adidas Adios Boost 2). Some runners’ running economy—or the energy needed to run at a given pace—improved by as little as 1.59 percent, while others improved by as much as 6.26 percent. That means, you guessed it, the average improvement was around 4 percent.
But a question remained: How do these shoes work in the real world with real runners? One of the more comprehensive analytical deep dives was done by The New York Times in 2018. In their analysis of half a million marathon and half-marathon race times posted to Strava (along with the shoes the runners were wearing), reporters Kevin Quealy and Josh Katz confirmed the 4 percent claim. Also, runners of the same caliber were more likely to hit a PR wearing the Vaporflys than other shoes.
“We found that the difference was not explained by faster runners choosing to wear the shoes, by runners choosing to wear them in easier races or by runners switching to Vaporflys after running more training miles. Instead, the analysis suggests that, in a race between two marathoners of the same ability, a runner wearing Vaporflys would have a real advantage over a competitor not wearing them.”
How do the Nike Vaporflys actually work?
The University of Colorado Boulder scientists who originally verified that the Vaporflys work as promised followed up with a study looking at how the components of the shoes —namely the carbon fiber plate and special ZoomX midsole foam—actually save runners 4 percent energy.
Published late last year in Sports Medicine, this study involved 10 male competitive runners doing 5-minute intervals in each of the same three shoes as their running economy study: Vaporfly, Zoom Streak, and Adios Boost. Using 3-D biomechanical stride analysis and force plates, the researchers examined how the runners’ gaits (the way they moved their limbs) and ground force reactions (how hard their feet were hitting the ground) differed between the shoes.
Based on previous studies where runners bent their knees less on extra-compliant (i.e., “squishy”) treadmills than on normal treadmills, the researchers expected that runners wearing the Vaporflys—which have extra-compliant foam—would bend their knees less.
“Why that would be important for energy is easy to imagine,” Wouter Hoogkamer, the lead author on the study, told Runner’s World. “Go stand up now and stand with straight legs, versus try to stand up now and bend your knees 90 degrees. See how you think you can last longer.”
However, none of the runners’ knee movements really differed between the three shoes.
Instead, it turns out the Vaporfly’s energy savings come from three things. First, runners’ ankle mechanics improve. This is likely thanks to the curved carbon-fiber plate that runs throughout the midsole from heel to toe; the researchers believe that the plate, in a sense, stabilizes your ankle and reduces your “rotational force”—or the work your calves would normally have to do.
Second, runners lose less energy by the plate keeping their toes straight, because yes, your toes work and waste energy when you are running by flexing. And third, the ZoomX foam in the midsole has two unique properties: an unusual degree of compliance (it squishes when your foot lands) and an unusual degree of resilience (it springs back to its original shape, returning most of the energy your foot applied when you landed). In fact, the shoe has 80 percent energy return in the heel, which is the highest we’ve ever measured in our Runner’s World shoe lab.
Hoogkamer admitted that there’s not much an average runner can take away from the study. But it might help you win a “should-the-shoes-be-legal” argument if you’re pro-Vaporfly.
“There’s a lot of people saying the [carbon fiber] plate functions as a spring, so if you have a strong opinion about that, then here’s some additional data to take into account,” he said. “Is it really the plate that’s the game-changer or not? For me, no. It’s the integration of the plate with the foam in this specific area that works so great.”
Could the Nike Vaporflys injure me?
One of the Vaporfly’s selling points is that they have more foam than most racing flats because the ZoomX midsole is so lightweight. In theory, this seems like it would cushion a runner against the impact of the ground—which could reduce risk of injury—but a study of extra-cushioned, or “maximal,” shoes found otherwise.
Researchers at Oregon State University-Cascades compared the biomechanics of 15 female recreational runners when they wore a neutral running shoe (New Balance 880) versus a maximal running shoe (Hoka One One Bondi 4).
Maximal shoes are claimed to lessen the shock of running on the body, because of their added cushioning, decreasing the odds of injuries like plantar fasciitis and tibial stress fractures. Therefore, the researchers expected that when wearing the maximal shoes, runners would experience a lower vertical impact peak—the highest amount of force when your foot initially lands—and loading rate—how quickly you load force onto your limbs as you move through your stride. However, the researchers found the exact opposite to be true: both measurements were higher in the cushioned shoes.
While this may seem like cause for alarm, JJ Hannigan, a post-doctoral researcher at OSU-Cascades and an author of the study, cautioned that there were a lot of other differences between the shoes besides just midsole cushioning that could have influenced the results. The stiffness of the midsole, the wideness of the heel, and the Hoka’s “rockered” bottom were just a few. “So it’s not as simple as ‘add cushioning, this happens, remove cushioning, this happens,’” he said. “If it was, we’d already probably know a lot more about the ideal running shoe.”
Given all of these differences between shoes, and because neither the OSU study nor the Sports Medicine study looked at the impact peak or loading rate of the Vaporflys specifically, it’s probably too far of a stretch to extend any of these findings to those shoes. Thus, the jury is still out regarding injury risk.
Will everyone wearing Vaporflys see the same 4% improvement?
The same University of Colorado Boulder researchers who verified the 4 percent claim of the Vaporflys examined what a 4 percent energy savings would mean for runners of different sizes and speeds. Through whole bunch of theory and math—which they just published in Frontiers in Physiology—they determined that the relationship between improvement in running economy and speed is not linear—that is, saving 4 percent energy does not necessarily mean you’ll run 4 percent faster.
Height and weight matter, as does the air resistance you encounter. Plus, running a little bit faster at already high speeds costs you more energy than running a little bit faster at slow speeds. Therefore, all other factors being equal (e.g., terrain, weather, turns), the faster you run, the less of an improvement you’ll see in your finishing time.
For instance, a 4-hour marathoner who saves 4 percent energy will run 4 percent faster (9 minutes and 36 seconds, or a 3:50:24 marathon), whereas a 2-hour marathoner will run only about 2.5 percent faster (3 minutes, or a 1:57:00 marathon).
What now?
If you want to see how much you might improve wearing Vaporfly shoes—given perfect conditions, of course—just plug your height, weight, and running speed into this online calculator, courtesy of the University of Colorado Boulder researchers.
And if you try running in the Vaporflys and decide that they’re too uncomfortable, or if you’re against running in any shoe that has a carbon fiber plate, Nike is now making other shoe styles (sans plate) with that same ZoomX foam, like the Pegasus 35 Turbo.
Foe me I’m hoping the latest and greatest Nike super shoes, the Alphafly 3, will get me a few minutes and maybe help me break sub three in marathon number forty eight in three weeks. I’ll need at least four minutes to better my Bibra Lake marathon time of 3:04 in July this year. I wore a pair of Saucony Endorphin Elites for that race, I’m hoping the Nike super shoe is a few minutes , at least, quicker. Why train harder when I can throw money at racing improvements. ?
Of course I’m not advocating giving up training altogether and relying on shoe technology to get you to the finish line but you’d being doing yourself an injustice if you didn’t give yourself the best chance of success, and that means a pair of super shoes. These days all the major shoe brands has a pair and truth be told they are much the muchness unless you’re chasing a sub two hour marathon? Also remember what I said earlier in the post, a runner never forgets their first time in a pair of super shoes, an incredible experience, the extra cost of the shoe is worth it just for that initial feeling.