80/20 Running: Run Stronger and Race Faster by Training Slower

by Matt Fitzgerald

You see, in order to yield steady improvement, a training system must be repeatable—day after day, week after week, month after month. And guess what. Hard running isn’t repeatable, either physically or psychologically. If you do too much of it, your body will burn out if your mind doesn’t first.

All too many runners wear themselves out by running too fast too often—now more than ever. There is an obsession these days with high intensity. Most of the trendy new training systems are focused on speed work. Running magazines, Web sites, and books can’t say enough about the magical power of intervals. Even champion runners are more likely to credit their speed work instead of their easy running when interviewed after winning a race. Yet the typical elite runner does eight miles of easy running for every two miles of faster running.

Too much hard running is the most common mistake in the sport.

Do 80 percent of your running at low intensity and the other 20 percent at moderate to high intensity. The rest is details.

New research also suggests that nonelite runners in the “recreationally competitive” category improve most rapidly when they take it easy in training more often than not.

Running too hard too often is the single most common and detrimental mistake in the sport.

Seiler started by exhaustively analyzing the training methods of world-class rowers and cross-country skiers. He found a remarkable consistency: Athletes in both sports did approximately 80 percent of their training sessions at low intensity and 20 percent at high intensity. In subsequent research, Seiler learned that elite cyclists, swimmers, triathletes, rowers, and—yes—runners did the same thing. Knowing this pattern could not possibly be an arbitrary coincidence, Seiler and other researchers designed studies where athletes were placed on either an 80/20 training regimen or a regimen with more hard training and less easy training. In every case, the results have been the same: 80/20 training yields drastically better results than more intense training.

Seiler’s rule also helps runners by explicitly defining low intensity. The boundary between low intensity and moderate intensity, according to Seiler, falls at the ventilatory threshold, which is the intensity level at which the breathing rate abruptly deepens. This threshold is slightly below the more familiar lactate threshold, which you can think of as the highest running intensity at which you can talk comfortably. In well-trained runners, the ventilatory threshold typically falls between 77 percent and 79 percent of maximum heart rate.

In pace terms, if your 10K race time is 50 minutes (8:03 per mile), your ventilatory threshold will likely correspond to a pace of 8:40 per mile. If your 10K time is 40 minutes (6:26 per mile), you will probably hit your VT at approximately 7:02 per mile. In either case, running at or below these threshold speeds will feel quite comfortable.

What I’ve realized—and what science proves—is that running slow just doesn’t come naturally to most runners. The same instinct that I had as an eleven-year-old new runner exists also within countless other runners of all experience levels. It’s an impulse to make every run “count” by pushing beyond the level of total comfort. This instinct makes a lot of runners rather hard to coach. It’s one thing to give a runner a training plan that is dominated by low-intensity workouts; it is quite another thing for that same runner to actually stay below the ventilatory threshold in all of those designated “easy” runs. I have discovered that unless a runner is systematically held back, he will more often than not run too hard on easy days and unwittingly sabotage his training plan.

But the runners who have taken a leap of faith and seen the process through have been well rewarded. Their runs have become more pleasant and less draining. They now carry less fatigue from one run to the next and they perform (and feel) better in the few runs that are intended to be faster. Suddenly, it no longer seems impossible to run an extra five or ten miles each week. The ones who take advantage of this opportunity improve even more.

More than once, after I had gotten him started on 80/20 running, he contacted me with questions like “Is it okay if I run faster on days when I feel really good?” Each time I counseled restraint and patience.

80/20 running is very simple. It has two components: planning and monitoring. The planning component entails creating or choosing a training plan that is based on the 80/20 Rule. In other words, the plan should be set up so that roughly 80 percent of your total training time is spent at low intensity (below the ventilatory threshold) and the other 20 percent is spent at moderate to high intensity. The monitoring component entails measuring intensity during each run to ensure you are executing your 80/20 plan correctly.

Embracing 80/20 running in your body means learning to slow down, which many runners, including Juan Carlos, find surprisingly challenging at the beginning, like removing a favorite junk food from the diet. Breaking the habit of pushing yourself during training runs takes some time, so I encourage you to get started right away, even as you continue to read about the 80/20 method.

Suppose I were to ask you to put down this book right now and run five miles at your choice of pace, but without wearing a watch. Chances are you would settle into a pace very close to the pace at which you did your last “easy” run, and the one before that, and the one before that. Odds are as well that this pace would put you above the ventilatory threshold, in the moderate-intensity zone.

There are really two problems here. The first issue is that your habitual running pace is doing to you what it did to Juan Carlos: hindering your progress. The second issue is that this pace is habitual. It feels natural and has become as familiar as your stride itself through experience. For this reason, your habitual running pace carries inertial force—like all habits, it is hard to break.

Why do most runners spend so much time running at moderate intensity? The discoverer of the 80/20 Rule, Stephen Seiler, found the reason may be that, unlike other forms of exercise, running has a minimum threshold of intensity. Very slow running is not running at all but walking. The average person naturally transitions from walking to running at a pace of roughly thirteen minutes per mile. If you start off at a slow walk and gradually increase your speed, you will find yourself feeling an urge to transition to running somewhere near that pace. Likewise, if you start off running and gradually slow down, you’ll find yourself wanting to transition to walking at about thirteen minutes per mile.

Naturally, the fastest way to get a distance-based task such as a five-mile run over with is to treat it as a race and go all out. Maximal efforts come with a good deal of suffering, however, and humans have a natural aversion to suffering that is at least as powerful as our natural inclination to “get ’er done.” So what do we do? We compromise between the desire to get the workout over with quickly and the desire not to suffer inordinately, and we end up doing the run (or the bike ride or the stair climb or whatever) at a moderate intensity.

Because the progress-hindering effect of running too hard too often is typically less than catastrophic, most runners are not only unaware that their “easy” runs are not easy, but they are also unaware that the mistake is hurting them.

There’s a song that says, “You only know you’ve been high when you’re feeling low.” Sometimes you need contrasting experience—something to compare your current situation against—before you realize things aren’t the way they ought to be.

If your optimal amount of sleep is eight hours per night and you routinely sleep seven hours, you may feel okay and be able to function fairly well during the day. It’s only when something in your life changes (perhaps a new job with a shorter commute) that allows you to get an additional hour of sleep that you realize how much better you could have felt and functioned all along. Similarly, runners often need to experience what low-intensity running really feels like before they realize how hard they normally work when they run and how much it’s been hindering their progress.

Heart rate monitoring in particular is an effective tool for getting runners to slow down, while pace targets are better for getting runners to push themselves in the 20 percent of their workouts when they’re supposed to.

The week of slow is the running equivalent of a juice fast. Some people use short-term juice fasts to hit the reset button on their diet. The fast is not an end in itself. The goal is to make permanent changes to their diet, replacing bad habits with good ones. But instead of just making these changes from one day to the next, they first take a few days to break their attachments to the old habits by consuming nothing but healthy fruit and vegetable juices. Then, once they are no longer craving potato chips or whatever else, they return to a normal but improved diet.

The next time you go for a run, go really slow. I mean, really slow. Don’t pay attention to your heart rate or pace numbers. All of that comes later. It’s perfectly okay if your pace on this run, and on all the runs in your week of slow, is even slower than you will be tasked to run on easy days in the 80/20 running program. You’re not really in training yet. The point of the week of slow is to get you ready for 80/20 training by setting you free from your habitual pace and teaching you to embrace running slow. So just find a pace that feels completely comfortable, utterly free from strain. I don’t care how much you have to slow down to reach this point—keep throttling back until you get there. If you’re embarrassed to be seen running this slow on your usual trail, find another place to run where you won’t be observed.

The biggest difference, however, is training. Early in his career, George ran no more than ten miles per week. Even when he set his long-standing mile record, he was averaging just three or four miles a day. Mo Farah started his career at seventy miles per week and moved up to 120 miles. This enormous difference in total running volume masks an even greater disparity in low-intensity running volume. Of the twenty-five miles Walter George ran in a typical week at his peak, sixteen were done at low intensity. Of the 120 miles Mo Farah runs in a typical week, close to one hundred are done below the ventilatory threshold. So, while Farah does just over 2.5 times more fast running than George did, he does six times more slow running.

The two most important variables in run training are volume (how much you run) and intensity (how fast you run). These two variables have been combined in every conceivable way over the past 150 years. There have been low volume/low intensity runners, high volume/low intensity runners, low volume/high intensity runners, and high volume/high intensity runners. Each of these general approaches has encompassed a full range of permutations. The particular high volume/low intensity combination of one hundred to 120 miles of running per week and 80 percent of total running time at low intensity was first tried by elite runners in the 1950s. By the late 1960s, it had driven virtually every other way of combining volume and intensity into extinction, and it remains in almost universal use by today’s elite runners.

In short, the 80/20 method has won the survival of the fittest, and there’s nothing left to try. Let’s see how it happened.

Here is a prime example of evolution at work in the sport of running. A young runner had come up with a novel training method that was different from what the established top runners of the day were doing. He then defeated those top runners in a major international competition. Afterward the losers were encouraged to copy the winner’s methods, which would become the new standard until another young runner came up with something better still.

Paavo Nurmi probably wished he were twenty years younger and could put Zátopek’s methods to use himself. At the peak of his career, Nurmi had run forty miles and walked twenty-five miles per week. This was more than the runners who came before him had done, and it was enough to make him the greatest runner in history. Known as the Flying Finn, Nurmi earned nine individual gold and silver medals in three Olympics between 1920 and 1928 and set numerous world records. Interestingly, Nurmi had been a rather mediocre runner until he added a relatively new method of training—high-intensity intervals—to his program. Workouts such as six times 400 meters in 60 seconds triggered a performance breakthrough that made the Flying Finn almost unbeatable for several years.

Although his speed-based training system had taken the sport forward from where it had stood when Zátopek found it, that system proved to be a dead end. He had shown that high-intensity intervals were a vital ingredient in the training of distance runners, but in the final analysis, it seemed their place was rather smaller than Zátopek (and Nurmi) had anticipated. If future generations of runners were going to run even faster, they would have to do so by some means other than speed-based training.

As a rugby player, he was accustomed to sprinting, and he had good raw speed. Lack of speed was not the cause of his humiliation. The problem was stamina. In fact, Lydiard decided, lack of stamina was also the reason he lost even shorter contests, including the half-mile and one-mile track races in which he routinely got thumped by local studs like Norm Cooper and Bill Savidan. Lydiard had more than enough horsepower to beat those guys. What he did not have was the capacity to sustain his speed.

This problem was not unique to him. Lydiard realized that no runner truly needed to get faster in order to race faster over middle and long distances, because no runner, regardless of how gifted or how well trained he was, could sustain anything close to his maximum speed for even half a mile. But some runners could sustain a greater percentage of their natural speed over long distances than others could, and it was those runners—not necessarily the “fastest” runners—who won races. Endurance was the true limitation in running. And if that was the case, Lydiard concluded, then training should emphasize endurance building. The process of getting in shape for races should be a lopsided effort to increase stamina to the point where a runner could run more or less forever. The secret to running faster was to run farther.

Lydiard learned that no matter how tired he was from recent training, he could almost always manage to run again if he kept the pace slow. But he did not always run slowly. Lydiard played around with the intensity of his running almost as much as he did with the volume. These investigations taught him that speed work helped the most when it was sprinkled lightly on top of a huge foundation of slow running. In essence, he invented 80/20 training.

His first regular training partner was Lawrie King, a young novice who worked alongside Lydiard at the shoe factory. In his first year of low-intensity, high-volume training, King struggled to a fifty-sixth place finish in the Auckland junior cross-country championship. A year later, he won the same race by seventy yards. A pattern was thus established that never changed: Lydiard’s mostly-slow approach did not work overnight, but runners who stuck with it improved steadily year after year. King went on to win the senior New Zealand cross-country championship and even set a national record for six miles.

“In theory,” Lydiard explained, “I am trying to develop my runners until they are in a tireless state. In practice, this means I am trying to give them sufficient stamina to maintain their natural speed over whatever distance they are running. Stamina is the key to the whole thing, because you can take speed for granted.

How do you give them the necessary stamina? By making them run and run and run some more.”

Over the next decade, a fascinating experiment was played out at the sport’s highest level. Early adopters of the Lydiard system competed against speed-based training loyalists in all the big races, which became proxy battlefields where the two training systems struggled for dominance through their athletic avatars. Lydiard-style training finally won, but victory was not achieved overnight. At the 1964 Olympics in Tokyo, the men’s 800 meters and 1500 meters were won by Peter Snell, one of Arthur’s boys; the men’s 5000 meters was won by American Bob Schul, who practiced speed-based training; and the men’s 10,000 meters was won by another American, Billy Mills, then a recent convert to the Lydiard system.

Such stories inspired yet more runners to take a chance on the Lydiard system. By 1972, it was impossible for a runner with any amount of natural talent to win on the world stage with speed-based training. At the Olympic Games in Munich, the winners of the men’s 800 meters (American Dave Wottle), 1500 meters (Finland’s Pekka Vasala), 5000 meters (Finland’s Lasse Viren), and 10,000 meters (Viren again) were all adherents of the low-intensity, high-volume way. But even then the Lydiard system had only begun to prove its might.

Eighteen months later, Rodgers won the Boston Marathon with an American record time of 2:09:55. Under Squires’ guidance, “Boston Billy” went on to claim three more Boston Marathon victories, lowering his American record to 2:09:27 in the 1979 race. He won the New York City Marathon four times as well. Table 2.1 offers a seven-day sample of Bill Rodgers’ training from two weeks before his first win in Boston. He ran 128 miles in those seven days. It is impossible to accurately judge intensity from the information Rodgers recorded, but my best guess is that the distances emphasized in boldface were run at or above the ventilatory threshold. If so, then Rodgers completed 104 of his 128 miles for the week—or 81 percent—at low intensity. He did not know it, but he was following the 80/20 Rule.

Perhaps the best proof of the potency of Lydiard’s de facto 80/20 running system as it was applied within the Greater Boston Track Club was what it did for many runners of less talent than Rodgers, Salazar, and Benoit. Take Dick Mahoney. Mahoney was working full-time as a mailman when he finished the 1979 Boston Marathon in 2:14:36. That time was good enough for tenth place, but it only got him fourth place among GBTC members, behind Rodgers (the winner), Bob Hodge (third in 2:12:30), and Tom Fleming (fourth in 2:12:56).

Kenyan runners would never have become the leading force in running that they are today if not for a fortuitous accident. British missionaries in Kenya endeavored to spread both Christianity and education there by building schools such as St. Patrick’s High School in Iten, which opened its doors in 1961. Many of the children who attended these schools ran to and from class daily, motorized transportation being a luxury few could afford. The missionaries certainly had no intention of putting thousands of Kenyan boys and girls on a low-intensity, high-volume running program, but that’s essentially what happened.

“When Swedish physiologists went to observe and analyze the training methods of the Kenyan runners,” Lydiard wrote, “they found that high school girls and boys were running on average about twelve or thirteen miles daily to and from school. Whereas the Africans would be running leisurely, trotting to and from school, their counterparts in the U.S. would be mostly on the track doing hard anaerobic repetitions. This is where the real problem lies.”

There is a popular belief that Kenyan runners do much more training at moderate and high intensities than do elite runners from other places, but the hard data does not support this myth. In 2003, top French exercise scientist Veronique Billat collected training data from twenty elite male and female Kenyan runners. A subsequent analysis of the data conducted by Stephen Seiler revealed that these runners did 85 percent of their running below the lactate threshold. Since the lactate threshold is slightly higher than the ventilatory threshold, these runners probably did very close to 80 percent of their training below the latter.

In one of his early studies, Seiler collected and analyzed data on the training of twelve elite junior cross-country skiers. He found that 75 percent of their workouts were devoted entirely to low-intensity training. When Seiler mixed all of the workouts together and looked at the actual time spent at each level of intensity, he saw that 91 percent of their total training time was spent below the ventilatory threshold. In other words, the skiers devoted slightly less than 80 percent of their workouts to low-intensity work and spent a little more than 80 percent of their total training time at low intensity.

When it was all said and done, Stephen Seiler had discovered that elite athletes in all endurance sports do approximately 80 percent of their training at low intensity.

The existence of this pattern in a variety of sports provides strong further evidence that the evolution of the 80/20 phenomenon in running was not arbitrary but instead came about as the optimal solution to the problem of maximizing human running performance.

Cycling, swimming, triathlon, and other endurance sports are close cousins of running. Although there are obvious surface differences (swimming is upper-body dominant, cycling is nonimpact, and so forth), at their core, all endurance disciplines are the same. Success in each of them depends on the ability to sustain aggressive submaximal speeds over long distances. The type of fitness that supports sustained speed in one endurance discipline differs only marginally from the type of fitness that does so in any other discipline.

This conclusion is true as far as it goes, but it does not support the notion that a speed-based training approach is better for runners and other endurance athletes than a mostly-slow approach. The reason, as Stephen Seiler well knew, is that the studies upon which it is based are far removed from the real world. For starters, the subjects are always nonathletes, never trained runners. How would the results of the Old Dominion study have differed if the subjects had come into the experiment having already developed their aerobic capacity with prior training?

Another thing to consider is that a VO2max test is not a running race. As we will see in the next chapter, running fitness encompasses more than just aerobic capacity.

Esteve-Lanao and Seiler presented their results in a paper published in the Journal of Strength and Conditioning Research in 2007. They concluded, “The present data suggest that if the runner can dedicate more time to daily training sessions, it seems better to design an ‘easy-hard’ distribution of load (increasing the amount of low-intensity training) than a ‘moderately hard–hard’ approach.”