Why we hit the wall in marathons, and how not to.
My first marathon was the 1999 California International Marathon in Sacramento. As I trained for it, many of my friends who were marathon veterans gave me the usual warnings to “respect the distance,” pace myself conservatively, and avoid setting too ambitious a goal. I truly believed that I would heed this advice, but I did not. My 6:06 first mile felt so easy that I decided to forge ahead at that pace. Consequently, by the 18-mile mark I was walking. I finished in 3:34, after having run the first half in under 1:23.
My second marathon was the 2000 Long Beach Marathon. I truly believed I had learned my lesson and started at a slightly more conservative pace than I had in Sacramento, despite the fact that I was now fitter. But by the 23-mile mark I was again walking. I finished in 3:11, a scant 26 minutes off my goal time.
Not until I ran my third marathon did I run my first halfway decent one. I finished in 2:46:42 at the 2001 Rock n’ Roll San Diego Marathon. Yet while I did not fall apart in this race as I had in my first two marathons, I still slowed substantially in the closing 5K. My average pace over the first 23 miles was under 6:20 per mile, but my last mile was run in the range of 7:30.
If I have learned only one thing from the 14 marathons I have now run it’s that pacing oneself optimally in a marathon is very difficult. The only marathons in which I have not run the second half substantially slower than the first are the few I have run non-competitively, as workouts. I don’t have this problem at shorter distances. My pace is almost always metronomically steady in 5K’s, 10K’s, and half marathons, even on my bad days.
I am hardly unusual in this regard. The vast majority of experienced runners are able to pace themselves well in shorter events but bonk to some degree before they reach the finish line in marathons. For example, in the 2007 California International Marathon, only 24 of the top 100 finishers managed to run the second half of the race no worse than one minute slower than the first. By contrast, in the 2008 Carlsbad Half Marathon, only eight of the top 100 finishers slowed to a similar degree.
Why is pacing the marathon so much more difficult than pacing shorter races? And for that matter, considering the fact that even the winner of most marathons runs the first half slower than the second, can we even assume that maintaining an even pace throughout the entire race is the optimal marathon pacing strategy? What can we do to improve our marathon pacing? Let’s tackle these questions one by one.
Why Is Marathon Pacing So Difficult?
There is a growing body of evidence that pacing in distance running events is governed by a brain-based mechanism that has been referred to as teleoanticipation. This mechanism continuously calculates the maximum pace that the runner can sustain through the remainder of a race without a catastrophic loss of homeostasis (such as overheating) occurring. The factors that are used in this calculation include conscious knowledge of the distance remaining, physiological “set points” such as the maximum allowable core body temperature, and feedback signals sent from the muscles and other organs to the brain. The results of the calculation are adjustments to the level of muscle activation (hence the runner’s pace) and perceptions of fatigue that serve to limit the intensity of exercise to the maximum level that will not cause serious self-harm.
Running experience plays a key role in calibrating this mechanism. When children do their first one-mile fun run, they invariably start at a full sprint and bonk within a few hundred yards. But this mistake teaches them to pace themselves much better in their next fun run. This process continues as long as the runner stays in the sport, so that eventually almost every runner develops a highly refined capacity to pace himself in races — except, perhaps, in marathons.
Research on pacing has shown that an evenly paced effort — often with a short finishing “kick” — produces the fastest finishing times in running, cycling, and other endurance time trials of more than a couple minutes’ duration. Experienced runners naturally tend to follow this pacing strategy in most races, which is manifest in the vast majority of world records set at every track race distance from 1,500 to 10,000 meters.
It stands to reason, however, that there is a limit to the computational power of the teleoanticipation mechanism. As race distances increase, there must come a point at which this mechanism can no longer comprehend the distance well enough to make an accurate calculation. There is clear evidence that almost all runners slow down in 100K ultramarathons. The highest finishers slow down least, but they’re still far from negative split territory. So it would seem that the limits of accurate teleoanticipation lie somewhere between 10,000 meters and 100 kilometers.
My research suggests that it’s on the short side of 26.2 miles for most runners, yet both the men’s and women’s marathon world records were run as negative splits. At the 2007 Frankfurt Marathon, Haile Gebrselassie ran the first half in 1:02:29 and the last half in 1:01:57. And at the 2003 London Marathon, Paula Radcliffe ran the first half in 1:08:02 and the second half in 1:07:23. Therefore it seems that the marathon is within the teleoanticipatory limits of the very fastest — or at least the best-trained — runners. It’s probably the best-trained runners, because there is no indication that pacing ability is linked to running talent, while there is abundant evidence that it is linked to running experience.
Is Even Pacing The Best Marathon Pacing Strategy?
The fact that most of the fastest men’s and women’s marathon times ever recorded involved negative splits would seem to be strong evidence that negative splitting, or at least even pacing, is the optimal marathon pacing strategy. One of the world’s top experts on pacing strategies, Ross Tucker, Ph.D., finds this logical irrefutable.
“I’m a big believer that there is such a thing as ‘natural selection’ when it comes to performance,” he wrote in an e-mail. “In other words, if the very best athlete runs a negative split, then that is most likely the optimal way [for everyone] to go about it. Because given that hundreds of world-class athletes are racing, time will eventually ensure that the optimal strategy is settled upon. If a positive split were better, I have no doubt that all the great athletes would be going out and doing it, simply because it works.”
However, just because even pacing seems to be the optimal pacing strategy for the world’s best runners doesn’t mean it’s automatically the best pacing strategy for you and me. There’s a large and possibly crucial difference in the fitness levels that elite and non-elite runners bring to the marathon event. It’s plausible to me that the more modest a runner’s fitness level is, the more likely it is that he will achieve his fastest time by running somewhat aggressively in the first half and then “hanging on” in the second half. Put another way, it’s plausible to me that the smaller the difference between the most comfortable pace a runner could sustain for 26.2 miles and the fastest pace he could sustain for the same distance, the more likely it is that a slightly positive pacing pattern would produce the best overall result.
Even the winner of most 100K ultramarathons runs a positive split, due to the extremity of the distance. Perhaps the standard marathon distance is almost as extreme for the average runner as the 100K distance is for the very best ultrarunners, making a positive split almost unavoidable. Just maybe, the average runner would have to hold back so much in the first half to run a faster second half that it’s just not worth it. If so, the average runner is better off just trying to avoid a precipitous decline in speed in the final miles.
I had an interesting marathon experience that increased the plausibility of this notion in my mind. I ran the 2007 Sacramento Cowtown Marathon as a training run. My goal was to run slightly under three hours, or approximately 12 minutes slower than I felt capable of running at maximum effort at the time. I wound up running the first half in 1:28:48 and the second half in 1:27:20. Despite restraining my pace from start to finish, I felt surprisingly fatigued in the last few miles.
Was I wrong in having believed I was capable of running a 2:48 marathon at the time? I don’t think so. I believe I could have run the first half of the marathon some four and a half minutes faster than I did and still hung on to run the second half at about the same pace. Because my fitness level was relatively modest at the time, simply finishing a marathon at a comfortable pace was going to take almost as much out of me as finishing it as fast as possible, therefore “saving energy” for the second half was probably not the optimal pacing strategy (or would not have been had I been aiming for maximal performance).
It is pure speculation on my part to suggest that modestly fit runners will typically run their best marathon time with a slightly positive split, where the second half marathon is run between, say, one second and two minutes slower than the first half. It would be very difficult to test this hypothesis scientifically. And there would be little point, because most runners will complete the second half of a marathon slightly slower than the first half even when they consciously aim for perfectly even splits, so my advice to all marathon runners is to try to run even splits. If you’re trying to break the world record, you will have to actually run even splits or possibly a negative split, whereas if you’re the average runner you should be content if your second half split is less than two minutes slower than your first.
You may also have to run even splits or better to lower your own personal best finishing time if you have run multiple marathons and lowered your personal best time to a point near your genetic limit. In this case, you are now more like an elite runner than an average runner.
How Can We Improve Our Marathon Pacing?
Effective race pacing may be defined as actually completing a race with the fastest time one is capable of completing a race. Let’s now take it as a given that every runner should try to run even splits or better in a marathon, although actually running a slight positive split might yield the fastest finishing time for most runners. What measures can you take to improve your ability to complete your next marathon with the fastest time possible? Here are five:
Run More Than One Marathon
The more familiar a specific racing experience is, the more effectively the brain’s teleoanticipatory mechanism will be able to do its job. If you’ve done it, or something very much like it before, then your brain will be able to compare the feedback it receives from your body and the environment to similar past experiences and make good calculations about the fastest pace you can safely maintain between your current location and the finish line.
Everyone agrees that nothing can prepare you for the fatigue you experience in the final miles of your first marathon. But after you have had this experience, you are better able to pace yourself effectively in future marathons. Most of this learning happens on a subconscious level. Your brain-body makes its way through your second marathon with a better sense of how you should feel at any given point in the race.
So treat your first marathon as a sort of experiment. Pace yourself cautiously but not fearfully and see what happens, knowing that, no matter what happens, you will pace yourself better in the next marathon for having done the first.
Set Appropriate Time Goals
Because the marathon distance is so extreme, few runners are able to effectively pace their way through a marathon entirely by feel, however, as they do in shorter races. You have to hold so much back when running a marathon that the early miles necessarily feel very easy — so easy that you could run five or 10 seconds per mile faster or slower and it would not feel noticeably harder or easier. But a pace difference of just five or 10 seconds per mile in the first half of a marathon could make the difference between hanging on and falling apart in the second half. So choosing an appropriate time goal, which in turn gives you an appropriate target pace, is very important.
Past marathon performances are the best source of information to use in setting future marathon time goals. In many cases, the most sensible goal is to beat your previous best time by a slight margin. How much of an improvement is realistic depends on how much better your fitness is during your current marathon ramp-up than it was in previous ones. Comparing your performance in recent workouts against your performance in similar workouts done at the same point in past marathon training cycles will give you a good feel for how high to reach.
Another good source of information to use in setting marathon time/pace goals is performances in shorter races. A race time equivalence table or calculator can be used to generate a predicted marathon time based on a finish time in a shorter event—for example a 10K. There’s a good race time equivalence table in Daniels’ Running Formula and a good calculator at mcmillanrunning.com.
Be forewarned, however, that these tables and calculators assume optimal training for each race distance. Optimal training for a marathon includes a lot more mileage than optimal training for, say, a 10K. However, most runners train far closer to optimally for shorter races than they do for the marathon. They are unwilling or unable to increase their mileage enough to make their marathon training truly equivalent to their training for shorter races. Thus, I have found that the race performance equivalence calculators tend to be very accurate from the 5K to the half marathon but overestimate performance for the marathon. Keep this in mind when using them.
Like marathons themselves, but to a slightly lesser degree, hard workouts serve to calibrate the teleoanticipation mechanism. Hard workouts expose your body to fatigue in ways that are similar to how marathons do, so they teach your body how fast and how far you can go before fatigue will occur. This internalized feel for your limits will help you pace yourself more effectively on race day.
The more marathon-specific a workout is, the more it will help you in this regard. Therefore, in the final weeks of training for a marathon you should do a handful of very challenging workouts that mimic both the speed and the endurance demands of your coming marathon. Here are three peak marathon workout formats that I recommend:
Long, Hard Run
1 mile easy
20 miles @ marathon pace + 20-30 seconds per mile
1 mile easy
14 miles at marathon pace
Pre-Fatigued Time Trial
10 miles easy
10K maximum effort
Run The First Half By Time, The Last By Feel
There are many runners who have completed 50 marathons, 100 marathons, and more. There are also many runners who routinely complete ultramarathons ranging from 50K to 100 miles in distance. For these runners, the 26.2-mile distance may be so familiar or manageable that they can effectively pace themselves exclusively by feel in a marathon. The rest of us cannot.
The rest of us need to pace ourselves initially by paying attention to actual pace data. Only after passing the halfway mark can we then safely go by feel, running the remaining distance at the fastest pace possible and using pace data only to monitor our pace rather than to actually control it.
If you have chosen an appropriate finish time goal and pace target and you accept that it is best to aim to run an even pace throughout a marathon, then it’s obvious how you need to handle your pacing after the starting horn sounds. Do your very best to run the first mile at exactly your goal pace time. Don’t run slower to “save energy” for the final miles, because it’s very unlikely that you will be able to make up time at that point, and don’t run faster to “put time in the bank,” as this usually results in a precipitous decline in pace after 20 miles.
At the one-mile mark, check your split and adjust your pace accordingly in the next mile. Continue trying to nail your target pace perfectly throughout the first half of the race. At that point, you will be able to rely on your teleoanticipation mechanism to guide your pacing the rest of the way.
If you own a speed and distance device, you can use it to show your real-time average pace throughout the race, so you don’t have to wait for mile marks to check whether you’re on pace. Just be sure to account for any known degree of inaccuracy in your device’s readings. I ran my last marathon with a speed and distance device that consistently tells me I’m running three seconds per mile faster than I really am. My target pace for the race was 6:05, so I tried to keep the average pace reading at 6:02.
Know The Course
Even pacing is not the same thing as an even distribution of energy. Even pacing becomes a very poor pacing strategy for the marathon when keeping an even pace requires sharp fluctuations in your rate of energy expenditure. Hills, of course, are the complicating factor here. When you’re running uphill you have to expend much more energy to hold the same pace you were holding on the level terrain that preceded the hill, and when you’re running downhill you can go faster with less energy than you can on level terrain.
You should try to keep your energy expenditure relatively even throughout a marathon, which means you have to slow down when running uphill and speed up when running downhill. This is something you will tend to do naturally, but instead of just taking the hills as they come, you should study the marathon course beforehand so you can factor the placement of hills into your pacing strategy.
For example, almost the entire first half of the Boston Marathon is downhill, while the second half is not. Therefore you should plan to run the first half at a pace that’s slightly faster than your target pace for the whole event. By contrast, the San Francisco Marathon is much hillier in the first half than in the second, so a planned negative split is definitely the way to go in this event.
Naturally, the hillier a marathon course, the slower you should expect your finish time to be. So if your main interest is running a fast time, choose the flattest marathon you can find, and then run it like a metronome!
Rachel C. , PhD
Research Scientist Consultant @ U-VIB
PhD, Doctor of Philosophy in Counseling
NREMT-P (National Registry of Paramedics)
– 911 Medic for over 15 years
– Scientist for over 7 years
– Runner for LIFE
source: Competitor By Matt Fitzgerald