Perception of Effort – 80/20 Endurance

Perception of Effort

Eliud Kipchoge is known chiefly for two things: winning and breaking records. He has won eleven of the twelve marathons he’s raced (finishing second in the only one he didn’t win). In 2017, he made the first formal attempt to cover the marathon distance in less than two hours, shocking the running world by coming up just 25 seconds short, and two years later he tried again and succeeded, covering 26 miles, 385 yards in 1:59:40. While this feat doesn’t count as an official marathon world record, Kipchoge owns that mark too, having clocked 2:01:39 in winning the 2018 Berlin Marathon.

In light of these facts, you might assume that Kipchoge is extremely focused on numbers and trophies, but he’s not. “I believe in a philosophy that says to win is actually not important,” he said in a 2016 speech at the Oxford Union. “To be successful is not even important.” What is important to Kipchoge is self-mastery, for which running marathons serves as a vehicle. “Only the disciplined ones are free in life,” he told his audience in the same address. “If you aren’t disciplined, you are a slave to your moods. You are a slave to your passions.”

When Eliud Kipchoge talks about running—not just in this instance but in general—he sounds more like a spiritual leader than some dumb jock. “It is better to conquer yourself than to win a thousand battles,” is a proverb attributed to the Buddha. Substitute “marathons” for battles and you have another Kipchoge quote.

Endurance racing is a spiritual experience for many athletes.

There’s nothing unique about Kipchoge in this regard. Endurance racing is a spiritual experience for many athletes. Indeed, it’s almost impossible for a spiritually sensitive person to experience endurance racing non-spiritually, which is why spiritual leaders including Sri Chinmoy, an Indian-born advocate of meditation and running influential in the U.S. in the late 20th century, have promoted it even to nonathletes. “The inner running and the outer running complement each other,” Chinmoy wrote. “For outer running, we need discipline. Without a life of discipline, we cannot succeed in any walk of life. So when we do outer running, it reminds us of the inner running.”

With the proper attitude, any activity—eating, gardening, you-name-it—can be undertaken as a spiritual exercise. But endurance racing is unique in that its spiritual aspect is almost inherent, so that even people who don’t initially pursue it for spiritual reasons end up doing so. Why is this?

Recent science guides us toward an answer to this question. It is evident to any athlete who has ever done an endurance race that the experience is challenging both physically and psychologically. In the past, exercise scientists believed that the limits athletes encountered in endurance races were physical in nature, and that the psychological challenges associated with approaching these limits were mere epiphenomena. The idea was that mechanistic factors such as lactic acid buildup in the muscles and depletion of muscle glycogen fuel stores prevented athletes from going faster and farther than they did. But we now know that this is not the case. While physical limits do exist, they merely constrain performance instead of limiting it directly. The limits that athletes encounter directly when racing are psychological.

What makes endurance racing different from sprinting is that, in a endurance race, the fastest way to get from the start line to the finish line is not to go as fast as you can. No human is physically capable of sustaining a true 100 percent effort longer than about 45 seconds. Therefore, in longer events, athletes must pace themselves, which means holding themselves back to a speed that can be sustained for the full distance. And pacing is done consciously, through a combination of cognitive and perceptual process. 

In particular, pacing is a form of predictive processing, where athletes continuously estimate the highest level of output they can keep up from their current position the finish line, adjusting accordingly. These estimates are based on perceived effort (or the athlete’s sense of how hard they’re working relative to maximum), past racing experience, and conscious knowledge of the amount of distance or time remaining n the race. Relying on these cognitive and perceptual factors, the athlete seeks to avoid 1) reaching exhaustion ahead of the finish line and 2) reaching the finish line before the point of exhaustion.

It’s important to note that when athletes do miscalculate and reach exhaustion ahead of the finish line, it is seldom because they have hit a hard physical limit like glycogen depletion. Rather, it is because they have reached the highest level of perceived effort they are willing to tolerate. They may feel physically incapable of continuing, but in fact they aren’t. Carefully designed studies have demonstrated that, at the point of quitting any type of endurance test, athletes always possess reserve physical capacity.

The psychological limit of perceived effort tolerance is no less real than the physical limits it protects athletes from ever actually encountering, but its nature is different. Imagine a row of weights arranged in order of increasing heaviness. Your task is to lift each weight in turn until you get to a weight that is too heavy for you to lift. When you do reach this point, there’s no doubt about it. You either can or can’t lift the next weight in the sequence.

By contrast, maximal perceived effort, similar to maximal pain tolerance, is mutable. This was shown in a study performed by Australian researchers and published in Pediatric Exercise Science in 2013. Thirteen children between the ages of nine and eleven years were asked to run an 800-meter time trial on three separate occasions. Because this was a novel distance for the kids, they were expected to improve their times over the three time trials through improved pacing strategy. And they in fact did improve, but not through improved their pacing strategy. In all three time trials, the kids started too fast, slowed significantly, and then sped up again toward the end. Their performance improved, rather, simply because they ran harder. In the first time trial, they ran as hard as they felt they could, and it hurt. But in the second one, having a bit of experience under their belts, they felt they could push a little harder and hurt a little more, and in the final time trial, knowing the second trial hadn’t killed them, they felt they could push harder still and hurt still more.

Experienced and highly motivated endurance athletes are capable of tolerating levels of perceived effort that are almost indescribably unpleasant. Because of this, and because the psychological limit of maximum tolerance for perceived effort is fuzzy, endurance athletes tend to find themselves in a special state of consciousness in the late stages of races. It’s essentially a shouting match between two distinct inner voices representing disparate aspects of the self. One voice, representing the instinctive desire to avoid discomfort that we all possess, is begging the athlete to quit, or at least slow down, while the other, representing the factors that motivated the athlete to pursue a goal that cannot be achieved without discomfort, is ordering the athlete to press on. Ambivalence occurs routinely in everyday life, but the internal dividedness athletes experience in the crisis moments of races is uniquely pure and intense.

Spirituality means different things to different people, but self-mastery is foundational to all spiritual paths. To live on a spiritual plane, whatever this may mean to you, is to live in accordance with your highest values, and this requires that you cultivate the ability to subsume your “lower” impulses to these values. In short, it requires self-mastery.

For millennia, humans have used tools such as fasting and meditation to pursue spiritual growth through self-mastery. These tools serve to foment a state of internal dividedness that presents the spiritual seeker with an opportunity to work at self-mastery. Traditionally, the inner battle that occurs during fasting or meditation is conceived of as being fought between flesh and spirit. From a scientific perspective, the battle is actually between different aspects of the mind rooted in different parts of the brain. The main battleground is an area of the brain called the anterior cingulate cortex (ACC), which is active in resolving ambivalence. Studies have shown that the ACC is exceptionally strong in both meditators and endurance athletes.

Both endurance athletes and meditators also score high on tests of inhibitory control, or the ability to override impulses through conscious restraint (a task that is handled by the ACC as well). Inhibitory control is not self-mastery itself, but it is one mechanism by which self-mastery operates.

Difference between endurance racing and traditional spiritual tools

One key difference between endurance racing and traditional spiritual tools of self-mastery is that endurance racing is competitive. It’s tempting to assume that the competitive drive stands in opposition to spiritual experience, and it certainly has this potential. For some athletes, racing is an largely expression of ego. But for others, competitive goals are merely a pretext for pursuing self-mastery. It’s a well-proven fact that athletes are able to push harder in a competitive context than outside of it, and the harder an athlete pushes, the greater self-mastery he or she attains. This is precisely why a spiritually sensitive athlete like Eliud Kipchoge who doesn’t believe that winning is important tries so hard to win.

Another key difference between endurance racing and traditional spiritual tools of self-mastery relates to the role of the body. In some spiritual traditions, there is a tendency to derogate the body and instinct. One of the reasons endurance racing appeals to me personally as a spiritual endeavor is that it celebrates our embodiment and places biology and instinct in the service of the quest to live in accordance with our higher virtues. Endurance racing certainly isn’t for everyone, but as a spiritually sensitive person who enjoys having a body, I’m very glad it exists!

In the context of endurance racing, pacing can be defined as the skill of distributing one’s effort across a defined distance in such a way that the distance is covered in the least amount of time possible. Although the body does the visible work in any kind of endurance race, the skill of pacing is entirely mental. There are three distinct psychological qualities that feed into it:

Three Distinct Psychological Qualities


A certain kind of intelligence is required to comprehend abstract distances and use this understanding as a factor in implicit calculations of the fastest rate of speed the athlete can sustain over the remaining distance of a race. Any animal predator can pace itself appropriately in relation to a target it can see, but only humans have the brain power to do so in relation to targets too distant to see. And human studies have shown a clear relationship between intellectual capacity and pacing ability. Like it or not, you have to be a certain kind of smart to pace well.


Pacing is done by feel. Although speed and power meters can be used as supplemental pacing tools, perception of effort gets the first in final say in determining how quickly an athlete covers a given race distance. To pace well is to know how you should feel at any given point in a race. This is a big reason why pacing ability automatically improves with experience. A really good pacer has an incredibly high level of sensitivity to perception of effort. If you ask the typical elite runner to give you a 6:00 mile, you are very likely to get something between 5:59 and 6:01, because these athletes can feel the difference between 5:58 and 6:02.


As I suggested above, pacing decisions are the results of implicit calculations. The main inputs to these calculations are knowledge of the remaining distance and perceived effort. These two inputs are factored together in a way that is intended to ensure that the athlete does not hit his limit before he reaches the finish line. But what is the limit? Not anything physical. It is simply the athlete’s sense of what he can and cannot do. As such, the limit is mutable, labile. Two athletes of precisely equal ability may have different limits because one believes he can’t go any faster and the other does, and only the other is right. Those athletes who have the highest performance limits relative to their physical ability simply have more guts. They aren’t afraid to push a little harder and find out if they fall apart or can keep it together.

A notably large fraction of the runners I interact with as a coach struggle with (i.e., suck at) pacing, and it is my perception—true or not—that this fraction is larger than it used to be. If so, why? I think a number of factors are at play. One is that today’s adult runners tend to be less experienced in the sport, having taken it up as adults instead of in school. Another is that kids have become less active generally, hence less sensitive to and tolerant of perceived effort throughout their lives. A third factor is that modern running gadgetry distracts runners’ attention from their bodies, creating a dependency on external feedback that further numbs sensitivity to perceived effort and ties runners to artificial limits.

This last factor affects even some elite runners, as Flagstaff-based 2:32 marathoner Sarah Crouch will tell you. But Sarah also offers us a good example of how to overcome this dependency. Her case study centers on the 2018 USATF 25K Championships, held on May 12. A few days before the race, Sarah announced that she would run it without a watch, citing frustration with her recent performances (she’d completed three half marathons in 2018, all more than five minutes slower than her PR of 1:12:10, which was set back in 2014) and the need to shake herself out of the rut she’d gotten stuck in. “I feel that when I’m wearing a watch and I’m constantly looking at it,” she said in an interview on the eve of the event, “I’m far too much in my own head. So the goal tomorrow is to race just by instinct, guts.”

Intrigued by the experiment, I made sure to watch the USATF 25K Championships live on the internet, and I’m glad I did. Last year I did some training with Sarah in Flagstaff, but the Sarah Crouch I saw on my computer screen on May 12thseemed like a different woman. She ran with a striking combination of aggression and serenity, her chin up and her eyes seemingly miles up the road as she dragged eight-time national champion Aliphine Tuliamuk behind her. Incredibly, Sarah passed the half-marathon point of the race in 1:12:45 on the way to finishing the race in third place.

Afterward, I contacted Sarah with a few questions, her answers to which, I felt, would help complete the lesson of her wildly successful gamble. If you struggle with pacing, pay attention!

Q: What is the precise nature of the problem you sought to address by racing without a watch last weekend?

A: As months and then years began to pass without a personal best at any distance, I became more and more obsessed with my pace during races. This year I’ve run three half marathons, each slower than the last, and I started to feel like I couldn’t break myself of the habit of looking at the watch every few minutes. During these races, the moment that my pace began to slip even a little, I fell apart, devastated that I was unable, yet again, to clip through miles at the same rhythm I’d managed easily earlier in my career. I finally realized that this was becoming a self-fulfilling prophecy in my races and I was reaching a point where something had to change. Choosing to abandon my watch at the 25K was honestly just a reflection of me reaching the boiling point and trying something new out of desperation.

Q: It seems to me that, in order for your experiment to work, you needed to have just the right mindset going into the race. Is this true, and if so, how did your specific mindset set you up for success?

A: That is absolutely true. This is going to sound nuts, but I almost had to separate the two people I’d become. The part of me that was growing larger and more powerful was the part of me that didn’t want to race, didn’t want to suffer anymore and didn’t believe I’d ever see another PR after almost half a decade of disappointment. That voice in me had grown so loud that it had almost completely drowned out the other voice, the one that I could barely hear anymore, the one that was dying to be let loose and compete. That part of me used to race recklessly, unafraid of anyone, and was always in pursuit of gutsy races and the pure joy that followed at the finish line. That part of me would literally eat a bowl full of dirt to beat the person next to me at the end of a race and frankly, that part of me does not need a watch.

During my warm-up for the 25K, I made a very deliberate decision to bring that voice back to the forefront, to let it make the decisions during the race, almost giving it its own personality and the permission to guide me through the race. I had no intention of leading until the moment that the gun fired and then all bets were off. My gut not only said to lead but to push the pace and try to break apart the lead pack as soon as possible. I was about 99% sure I was running a suicidal pace but I couldn’t have cared less. For the first time in four years, I felt like me again. Turns out, I almost had the fitness to back it up as I couldn’t match the move made eleven miles into the race, but I wouldn’t go back and change the way I ran for anything. I wouldn’t go back and sit comfortably in fourth or fifth and try to progress with 10K to go, which, on paper, may have been the smart thing to do. Sometimes you need to do the brave thing, not the smart thing.

Q: You ran faster than you had in a while. One might assume that, to do so, you had to suffer more. But was that really the case, or did your mental approach somehow enable you to run faster without feeling “worse”?

A: No, I did not suffer more, but my willingness to suffer was greater. I do think there is something to the notion of dwelling less on the pain and more on the product of it when you feel like you’re having the race of your life. Perhaps focusing on the end rather than the means is made easier when the end is decidedly worth it. I’ve described the feeling before as the fingers of human experience outgrowing the glove of human flesh. It’s incredibly difficult to describe to someone who hasn’t experienced it, but pain with purpose is far easier to accept than the pain that accompanies a poor race.

When your incentive to hurt is higher, it not only permits you to drag yourself deeper down the rabbit hole of pain, it adds the remarkable sensation of life, raw life, into the experience. Humming under the strain of the pace out there, I felt very aware of my surroundings, the bright green of the trees, the sound of my competitors’ shoes slapping the pavement, the scent of rain in the air. Yes, it may have hurt like hell, but I feel bad for those who have never pushed themselves past their limit to find out what was on the other side because the other side is spectacular.


Interested in learning more about pacing? My new book, On Pace: Discover How to Run Every Race at Your Real Limit will guide you step by step toward pacing mastery. Click here for a free sample chapter of On Pace, and here to purchase a copy.


If you ask the average running coach what good running form is, he or she will probably answer with phrases like “midfoot strike,” “high stride rate,” and “low vertical oscillation.” It is true that these and other form characteristics are common in top runners and less common in slower runners. But there are exceptions. Meb Keflezighi won the 2009 New York City Marathon as a heel striker, Ryan Hall set an American record of 59:43 in the half marathon with an unusually bouncy stride, and Mo Farah won 10 Olympic and World Championships gold medals with an exceptionally low stride rate.

The Basis of a Good Running Form

On the basis of the fact that no two champion runners run the same way, I would argue that no specific movement pattern defines good running form. What, then, is the true essence of good running form? One possibility is efficiency. This idea has a lot going for it. After all, what is it that you really want your running form to do as distance runner? Not maximize power–that’s for sprinters. Rather, you want your running form to minimize the energy cost of running so you can go faster and farther before you become exhausted. It doesn’t matter how you minimize the energy cost of running, biomechanically, but only that you minimize the energy cost of running. Obviously, some movement patterns are generally more efficient than others, which is why most of the best runners are midfoot strikers. Nevertheless, each body is unique, so we shouldn’t expect every runner to minimize energy cost in the same way.

As sensible as it seems to define good running form as that which maximizes movement economy in an individual runner, however, I think this definition misses the mark as well. The true definition of good running form, I believe, is the particular way of running that feels easiest to an individual runner. I can’t claim to have come up with this theory. I got it from Samuele Marcora, father of the psychobiological model of endurance performance. Here’s an excerpt from an email message Marcora wrote to me about his perception-based theory of biomechanics:

“Many specialists in this area. . . still think that the [central nervous system] controls locomotion to optimise energy. They envisage an optimal solution in which the CNS senses energy expenditure and adjusts locomotion parameters (e.g., step frequency) to minimise energy expenditure. There are some basic neurophysiological problems with this proposal. However, the biggest problem is that there are several instances in which the CNS chooses locomotion parameters that optimise perception of effort at the expenses of energy expenditure (e.g., walking to running transition). When energy seems ‘optimised’ this coincides with the optimal perception of effort as well. So perception is always optimised but energy expenditure is often not. The. . . conclusion is that the CNS optimises perception of effort rather than energy expenditure.”

Energy expenditure and perceived effort are closely linked. For the most part, movement patterns that reduce energy expenditure also make running feel easier. It is very likely that the evolutionary reason individual runners adopt the particular way of running they do is to minimize energy expenditure. But it is perceived effort that actually controls this process. In other words, running in the way that minimizes perceived effort is the means by which runners achieve the end of minimizing energy expenditure.

Consider what happens when you’re running along and you turn into a strong headwind. You hunch forward, don’t you? This natural adjustment reduces the surface area of your body and minimizes the energy cost of running into the wind. But the choice to hunch is made consciously, and what you are really doing as a living organism is trying to make running feel as easy as possible despite the headwind. What Marcora and I are suggesting is that this is what runners are doing all the time, although mostly in subtler ways not involving headwinds.

Perception of effort is tied to brain activity. In crude terms, the harder you have to think about your movements, the harder those movements feel. So your goal as a runner is to run as thoughtlessly and unconsciously as possible. This is why consciously changing the way you run is such a bad idea. No matter what you change, you will have to think more about what you’re doing because what you’re doing is unnatural, and this will make running feel harder.

This does not mean you are stuck with your current stride forever. Every runner’s stride evolves gradually over time as the CNS learns through repetitive practice how to move in ways that feel easier (and that usually also reduce energy cost). Consider something like running with a higher stride rate. If you force yourself to run with a higher stride rate right now, running will feel harder (if only very slightly) and you will probably also be less efficient because you have to think about what you’re doing. But guess what? If you just leave your stride alone and keep training, it is probable that your stride rate will increase somewhat over time, and this natural evolution will be associated with reduced perception of effort and likely also with increased efficiency. You have to earn your stride changes.

Evidence that thinking about your running is bad for your running comes from studies in which researchers look at the effects of attentional focus on running economy. A series of experiments conducted by European researchers has shown that runners become less efficient when they focus their attention internally versus externally, even if their internal attentional focus does not involve any effort to alter their running form. Let that sink in for a minute.

I only wish these researchers had measured the effect of attentional focus on perceived effort as well, because it is perception of effort, not physiology, that directly limits endurance performance. Becoming more economical doesn’t do a runner any good if this benefit comes at the cost of increased perception of effort, as no runner can run faster than he feels he can run. And based on his understanding of what good running form really is, Marcora believes it would be a mistake for runners to try to increase their economy through interventions requiring conscious form changes (i.e., internal attentional focus, i.e., thinking), even if these interventions actually worked. “What happens to perception of effort if we make people run in the way that gets the lowest energy expenditure?” he asked in our email exchange. “I bet it would go up considerably.” And when perceived effort goes up, performance goes down, because the definition of good running form is the particular way of running that feels easiest to an individual runner.

Pacing is the art of getting to the finish line of a race in the least amount of time possible given the current state of your body (fitness and fatigue levels, etc.) and external conditions. Generally, this requires that you distribute your effort quite evenly throughout the race and that this evenly distributed effort leave you tired enough in the approach to the finish line that you are able to speed up a little but not much.

It has been my observation as a coach that most runners aren’t very good at pacing. Knowing a thing or two about the science of pacing, I am not surprised by the pervasiveness of this weakness. There is no test, calculator, or device that can tell a runner how to pace a race optimally. Pacing is and always will be a form of guessing based on subjective perceptions. Specifically, pacing entails using perception of effort, or your global sense of how hard you are working, to adjust your speed so that, at every moment throughout a race, you feel you are running at the highest speed you can sustain to the finish line. In other words, pacing is a skill that requires you to interpret a feeling (perception of effort) through the lens of external information (your conscious knowledge of how far away the finish line is) to make a prediction (whether you can sustain your current speed to the finish line) that could yield disastrous consequences if it is even slightly inaccurate. Not easy.

Try this Simple Pacing Games

Like all skills, though, pacing ability can be improved. As a coach, I try to help my athletes become better pacers by incorporating simple pacing games into their workouts. Each of these exercises offers an opportunity to practice linking perception of effort with external measures, which is the essence of the skill. Give them a try!

Human Autosplit

Turn on the autosplit function on your running watch so that you are notified when you’ve completed each mile (or kilometer) of a run and the time is captured. Throughout your low-intensity easy runs and long runs, when you hear your watch beep to signal a completed mile or kilometer, try to guess your split time to the exact second before you look at the display. If you do this consistently, making it a habitual component of every low-intensity run, you’ll get really good at it.

Metronomic Repeats

In workouts that feature intervals or repeats of a uniform distance, try to run precisely the same time (down to the tenth of a second in shorter intervals) in all of them. For example, suppose your workout comprises 6 x 1 mile at 10K race pace with 1:00 rests between repeats. If you happen to run the first mile in 6:22, do your best to run each subsequent mile in 6:22 also. Obviously, to get the desired training effect from such a workout, it’s enough to just be in the right ballpark with your interval times. But by raising your standard of consistency, you will get a second benefit from the workout, which is improved pacing ability.

Thin-Sliced Cutdowns

Cutdown intervals are intervals of a uniform distance or duration in which you try to run each one a little faster than the one before. Cutdown interval workouts that feature a large number of intervals offer an excellent opportunity to refine your control of effort.

One such workout, which I learned from HOKA One One Northern Arizona Elite coach Ben Rosario, consists of 10 x 1:00 uphill, where you are required to cover more distance in each rep than you did in the one before, finishing with an all-out effort. Obviously, you could cheat by walking the first rep, then speed-walking the second, and so forth. But the idea is to do the first rep at an honest effort that leaves just enough room to increase your effort nine notches more through the remainder of the session.

When I do this workout, I carry an extra pair of socks. At the instant I complete the first 1:00 hill repetition, I toss down a sock as a marker. In the next rep, I toss down the second sock, hoping to get about 10 feet beyond the first sock when a minute is up. Then I pick up the first sock while jogging back down the hill to my starting point, and so on.

Research suggests that all runners get better at pacing automatically through the process of accumulating training and racing experience. Indeed, there is no substitute for experience when it comes to mastering the skill of pacing. However, you will improve more quickly if your consciously and routinely practice your pacing through games like those I just described than you will if you just train without ever really thinking about pacing.

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