In last week’s blog post I mentioned that two new studies related to the phenomenon of VO2max had been published recently, and I described one of them, which showed that sustainable power declines more shallowly with increasing time in cyclists with higher VO2max scores. Today I’d like to tell you about the other study I alluded to, which sheds just as much light as the first on the phenomenon in question, but from a different angle.

This one was conducted by Benedito Denadai and Camila Greco of Paulista State University in São Paolo, Brazil, and published in the journal Current Research in Physiology. It was premised on the observation that, in any group of runners of different abilities, VO2max is a very good predictor of performance in races of any distance, whereas in a group of elite runners, VO2max has less predictive power at any distance. More specifically, in any mixed group of runners there will be a wide range of VO2max values, and those with higher values will tend to perform better in races of all distances. But among elite runners, VO2max values are relatively homogenous, and although some elites will perform better than others at either middle distances, long distances, or ultra-distances, few will perform better than others at all distances and the small differences in VO2max values among these runners fail to account for individual superiority at any distance.

This suggests that other components of fitness besides VO2max also make an important contribution to race performance, and that these components differ by race distance. The purpose of Denadai and Greco’s study was to identify these distance-specific contributors to race performance in elite runners. To fulfill this purpose, the two scientists conducted a retrospective analysis of data from past studies using elite runners as subjects. With the aid of sophisticated statistical tools that I don’t understand, they were able to evaluate the relative strength of each fitness component’s contribution to performance in races of various distances.

Here’s what they found: For 1500m specialists, velocity at VO2max (or vVO2max) is the strongest predictor of performance. A high vVO2max comes from having a high aerobic capacity and good running economy. At the 3000m distance, vVO2max and blood lactate response to exercise were coequal predictors of performance. Specifically, the velocity at which a runner’s blood lactate level reached 4 mM predicted performance as accurately as did their velocity at VO2max. This is not surprising, because the ability to attain high velocities at low blood lactate levels is also rooted in aerobic capacity. For runners specializing in the 5000m and 10,000m track events and the marathon, velocity at lactate threshold (2 mM) is the best predictor of performance. While related to velocity at 4 mM, this component of fitness is slightly different, having more to do with the ability to avoid producing lactate through aerobic metabolism at a high rate than the ability to metabolize lactate itself.

Velocity of lactate threshold is also the best known predictor of performance in elite ultrarunners, according to Denadai and Greco, but I say “known” because research on athletes in this category is sparse. I’d be willing to bet that respiratory exchange ratio (RER) is a stronger predictor of performance at ultra-distances than it is at shorter distances. RER is the velocity at which carbohydrate metabolism overtakes fat metabolism as the primary source of muscle energy and it comes from having a high fat-oxidation capacity.

Overall, the findings of this study underscore the need for limited specificity in training. To a great extent, fitness is fitness in running regardless of which race distance you specialize in. We see this in the fact that all elite runners have a high VO2max. Whether you race the 1500, 10K’s, marathons, or ultras, your training should focus on developing your aerobic capacity. However, fitness is not exactly the same across the spectrum of race distances. At each distance, athletes need a little more of certain fitness components, and a little less of certain others, than they do at other distances.

This is where specificity comes in. The hardest workouts a runner does in their heaviest period of training should simulate the specific demands of their event. For 1500m runners, short intervals (1-3 minutes) run at or near vVO2max fit the bill. For 3000m runners, such workouts should be coupled with somewhat longer intervals at a slightly lower intensity. For 10,000 specialists, long intervals and tempo efforts run between critical velocity and lactate threshold velocity are the best peak workouts. Marathoners should couple these workouts with sustained efforts run between half-marathon and marathon pace, and ultrarunners, of course, should make multihour long runs the hardest workouts they do in their heaviest period of training.

Ain’t science neat?

The concept of a limiting rate of oxygen consumption during exercise, or VO2max, has existed since 1923. For almost a century, we’ve known that oxygen consumption increases as the intensity of exercise increases, that some people are able to consume oxygen at a higher peak rate than others, and are therefore able to exercise more intensely, and that training increases an individual’s highest achievable rate of oxygen consumption, and with it their exercise capacity. No other phenomenon has been as exhaustively in exercise science. Just now I performed a keyword search of “VO2max” on PubMed and got 11,752 hits.

You might think that by this point there would be nothing left to learn about the phenomenon. But if you did, you’d be wrong! Two new studies touching on VO2max have been published within the past few weeks alone. I’d like to tell you about one them here, as it offers practical lessons for everyday endurance athletes like us.

Cyclists and triathletes often use a 20-minute time trial to estimate their functional threshold power (FTP), which is the highest wattage an athlete can sustain for 60 minutes. Obviously, no athlete can sustain quite as much power for 60 minutes as they can for 20 minutes, so a simple formula is used to estimate 60-minute power from the result of a 20-minute test. All the athlete has to do is multiply their average wattage in the test by 0.95. For example, if you average 226 watts in your 20-minute time trial, your estimated FTP is 206 x 0.95 = 215 watts.

This one-size-fits-all formula is based on the assumption that athletes are able to sustain 5 percent less power for 20 minutes than they can for 60 minutes. But does this formula really fit all athletes? That’s the question Sebastian Sitko of the University of Zaragoza and colleagues sought to answer in a study published recently in the Journal of Science and Medicine in Sport.

Eighty-seven cyclists representing a range of abilities were statistically separated into four groups: recreationally trained (average VO2max 46.9 ml/min/kg), trained (average VO2max 59.5 ml/min/kg), well trained (average VO2max 66.4 ml/min/kg), and professional (average VO2max 74.3 ml/min/kg). All of the subjects completed a 20-minute time trial that was used to estimate each individual’s FTP through the aforementioned formula. Subsequently, they performed a second test that required them to pedal at their estimated FTP as long as possible.

Here are the results: On average, the recreationally trained cyclists were able to sustain their estimated FTP for 35 minutes, while the trained cyclists lasted 42 minutes, the well-trained cyclists 47 minutes, and the professional cyclists 51 minutes. As we see, the Allen & Coggan test (as it is known) tends to overestimate FTP, and the lower your VO2max is, the greater the error is likely to be. The reason is that the rate of decline in sustainable power over time is steeper for less aerobically fit athletes, who are less fatigue resistant.

This becomes a problem for athletes who base their training zones on the one-size-fits-all formula proposed by Allen & Coggan. An athlete with a VO2max of 47 who uses 95 percent of 20-minute power as their FTP will probably end up with zones that are too aggressive and will consequently train too intensely. This doesn’t mean we have to dispense with the protocol altogether; it just means that athletes of different levels need to use different multipliers to generate an accurate estimate of FTP from the result of a 20-minute time trial.

My suggestion is to use the same result to calculate your power-to-weight ratio, which is a decent proxy for VO2max, hence a good way to determine your level as a cyclist and select an appropriate multiplier for estimating FTP. Simply divide your 20-minute power by your weight in kilograms, see where this puts you on the table below, and use the recommended multiplier to calculate your FTP.

Power-to-Weight Ratio
Men <2.9 W/kg 2.9-3.8 W/kg 3.9-4.8 W/kg >4.8 W/kg
Women <2.1 W/kg 2.1-3.0 W/kg 3.1-4.0 W/kg >4.0 W/kg
Multiplier 0.92 0.93 0.94 0.95

Let’s go back to our earlier example of an athlete who averages 226 watts in a 20-minute time trial. Now let’s suppose this athlete weighs 73 kg (160.6 lbs), which gives them a power-to-weight ratio of 3.1 W/kg, and let’s also suppose the athlete is male. Referencing our handy-dandy table, we see that the appropriate multiplier for estimating FTP is 0.93, which yields a result of 210 watts. That’s a number the athlete is more likely to be able to sustain for a full hour than the 215 watts we got from the Allen & Coggan formula and will generate power zones that better fit the athlete. Now you try!

When I was a younger man I used to shake my head in pity when reading the writings of endurance sports experts of a certain age. They tended to repeat the same things over and over, evidently because they had nothing new to say. Because they hadn’t learned anything new about their field of expertise since they were young themselves. Because they hadn’t bothered to try to continue learning. At some point, it seemed, they had simply decided they knew their stuff and stopped seeking out new knowledge.

These aging authorities struck a sad figure in my eyes. As a young man aspiring to expertise in endurance sports, and who therefore payed close attention to new and recent developments in them, I recognized that certain members of the old guard were being left behind, and worst of all, that they failed to recognize their own waning relevance. With the boldness of youth, I vowed never to put myself in such a pathetic position.

Time flies, and now I am a man of a certain age. And, God help me, I feel myself slipping a bit knowledge-wise. Granted, age is not the only factor in my case but also illness. For many years I relied on my own training and racing to stimulate new learning. Long covid has stripped me of my ability to do these things, forcing me to look elsewhere for knowledge. But I can’t blame poor health entirely for my slippage. I can feel my brain slowly transforming from an absorbent sponge into an impenetrable fortress, a normal part of aging. I have less and less patience for technology, for example.

Nevertheless, it remains the case that I don’t want to fall behind, so I pounced when Philip Skiba announced the release of his new book Scientific Training for Endurance Athletes, a review copy of which the author was kind enough to send me. I couldn’t have picked a better way to fill the emerging gaps in my knowledge of endurance training. Skiba is a heavyweight in the field, a technical savant who holds both a medical degree and a doctorate in exercise physiology, has coached a number of elite triathletes, and served as a consultant to Nike’s Breaking2 project.

True to his scientific leanings, Skiba takes a bottom-up approach to explicating how to train for endurance racing, going from physiology to intensities to workout types to periodization. Personally, I prefer a top-down approach that starts with real-world best practices, as I believe that context is everything and that, for this reason, it’s impossible to deduce best training practices from physiology. That being said, Skiba’s approach serves mainly as a pedagogical device, and it does an effective job of making sense of endurance fitness and training objectives. Indeed, Skiba has a special gift for making science understandable to the layperson, of which I am one. My favorite passage in the entire book is his house metaphor of endurance fitness, which goes like this:

The foundation is your basic strength and resilience. The floor is your endurance capacity, and the ceiling is the critical power/speed. The roofline is your VO2max. The top of the roof is your peak power output. Let’s imagine that your current marathon speed (usually very close to lactate threshold) is equal to your height. You walk into your house, and mark your height on the wall. With time, as you train, you grow taller. In the beginning, the whole house grows with you. However, what you will find is that with time you will begin to bump your head against the ceiling. You need to do some specific renovations on the house to raise the ceiling so that you can continue to grow. However, what you will quickly find is that you are squeezing the ceiling too close to the attic above. Eventually, you need to raise the attic as well.

Skiba's House Metaphor
Skiba’s House Metaphor

Overall, I found Skiba’s book reassuring. While I learned a lot from reading it, including how to calculate optimal interval numbers for individual athletes based on their current fitness, for the most part it confirmed what I already knew and left me feeling I haven’t yet fallen as far behind as I had begun to fear. The book also heightened my sense that, increasingly, the folks who really know what they’re talking about with respect to endurance training are speaking the same language. With his focus on the power-duration curve, which represents fitness in terms of how long an individual athlete can sustain a given power output or velocity across the spectrum of effort levels, Skiba approaches the problem of developing race-specific fitness through the same lens as the likes of Stryd, Alan Couzens, and yours truly.

Scientific Training for Endurance Athletes isn’t for everyone, but it has become the very first book I recommend to performance-minded athletes who want a thorough and up-to-date understanding of how endurance training works and how to make it work best. Already I’ve purchased a copy for Coaches of Color Initiative apprentice Jessica Schnier, added it to the Resources section of the forthcoming 80/20 Endurance coaching textbook, and convinced a couple of the athletes I coach to order it. And you can soon expect Dr. Skiba to be a guest on the 80/20 Endurance podcast, where we’ll dive much deeper into his impressive work (and I don’t just mean impressive for an old guy!).



Many moons ago, I wrote a post for this blog that bore the title, “The Human Body Is Not a Smartphone.” In it I argued that endurance training methods cannot advance indefinitely in the way that technologies such as smartphones can. “Once the best ways to train and fuel the human body for distance racing have been discovered,” I wrote, “it is impossible to improve upon them further until and unless the human body changes enough for different methods to become optimal.”

Even as I composed these lines, I knew they weren’t completely true. The idea that, given enough time, the optimization of endurance training methods is more or less inevitable is based on the notion that endurance sport operates as a self-organizing system. “A what?” you say. A self-organizing system.

Data scientist David Green of Monash University defines self-organization as “the emergence of pattern and order in a system by internal processes, rather than external constraints or forces.” Natural evolution is the best example of a self-organizing system, but computer scientists and engineers are able to create artificial self-organizing systems that are capable of evolving optimal solutions to real-world problems such as managing runway traffic at airports. If you place a graph representing such an evolutionary process next to a graph representing improvement in, say, the men’s marathon world record from 1896 to today, the two curves will appear uncannily similar in shape—a compelling illustration of endurance sport’s self-organizing behavior.

There are important differences between human endurance sport and computer models of airport throughput, however. Most notably, endurance sport is a social system nested inside the larger societal system, and as such it is subject to certain braking forces on its evolution that manmade self-organizing systems are not. Tradition is one such factor. In my experience, the top endurance coaches don’t put as much effort into innovating as they might, and I think that’s simply because, as human beings, top endurance coaches are deferential to “the way things are done” in the sport, no different than how teachers are deferential to the traditions of the institution where they teach. Consequently, opportunities to do things a little better sometimes wait a little longer to be discovered than they do in tech.

Which brings us to the topic of this article. The innovation known as block periodization originated in the weightlifting realm, where the practice is widespread. In the endurance realm, the term carries a slightly different meaning and the practice is not as widespread. As it applies to endurance sports, block periodization entails separating the volume and intensity elements of training. For example, a runner might do a block of three high-intensity workouts one week and a block of six longer low-intensity workouts the next week.

The developers of block periodization saw it as a way to make training harder without making it more stressful. They presumed that elite athletes were already training as hard as they could in the traditional way, where high-volume, low-intensity interval training and high-intensity interval training are mixed. It seemed plausible that by separating these two different types of training, athletes could do more of both without necessarily doing either in excess. During high-intensity training weeks, athletes would not be limited by fatigue induced by long workouts at low intensity, and during volume weeks, athletes would not be limited by fatigue induced by high-intensity intervals workouts.

Among the leading scientific investigators of block periodization in endurance athletes is Bent Rønnestad of Inland Norway University. In a 2019 meta-analysis of his and others’ work in this area, Rønnestad and colleagues concluded, “Block periodization is an adequate, alternative training strategy to traditional periodization as evidenced by superior training effects on VO2max and [maximal power output] in athletes. The reviewed studies show promising effects for BP of endurance training; however, these results must be considered with some caution due to small studies with generally low methodological quality.”

The most recent study of the effects of block periodization was conducted by Polish researchers and published in the International Journal of Environmental Research and Public Health last month. Twenty competitive mountain bikers were separated into two groups. For eight weeks, members of one group followed a traditional periodization model where each week included a mix of low-intensity riding, high-intensity interval work, and sprint interval training, while the second group followed a block periodization model where 17-day blocks of low-intensity riding were alternated with 11-day blocks of HIIT and sprint interval sessions.

Both groups underwent physiological and performance testing before and after the eight-week training period. Improvements were about equal in the two groups in all measures except VO2max, where the traditional periodization group experienced bigger gains, going from 3.66 to 4.2 L∙min−1 compared to 3.75 to 4.0 L∙min−1 in the block periodization group.

Where does this leave us? For better or worse, training innovations that are disruptive to existing best practices need to have a better story to tell than “possibly slightly superior in some metrics according to some but not all studies” if they are to overcome the inertia of tradition. I stand ready to be an early adopter of the next such innovation that comes along, but block periodization probably ain’t it.

Callum Hawkins came into the 2018 Commonwealth Games Marathon in Australia with high expectations. Having set a national record of 1:00:00 for the half marathon and finished fourth in the World Championship Marathon the prior year, the 25-year-old Scotsman was supremely confident in his ability to claim a gold medal for his small, proud country. His strategy–despite expected temperatures in the mid-80s–was to run hard from the start and demoralize the other contenders. This bold but risky plan played out exactly as Callum imagined it, and with just 2 miles left in the race he held a commanding 2-minute advantage over defending champion Michael Shelley of the host nation.

And that’s when the wheels came off. Trapped inside his body by the ambient heat of the day, the metabolic heat generated by Callum’s hardworking muscles, having accumulated steadily throughout the marathon, crossed a dangerous threshold as he approached the 40 km mark. He began to weave back and forth across the road like a blindfolded drunk in a hurricane. It was only a matter of time before he went down, but he managed to stay upright far longer than an actual blindfolded drunk in a hurricane would have done before pitching over onto a grassy verge on the side of the road. Spectators watched with a lack of visible alarm that I can’t imagine myself showing in their place as Callum tried repeatedly to hoist himself upright, now looking like a boxer trying to beat a 10-count, succeeding on his third try.

Still leading, he lurched along in a grotesque approximation of human bipedal locomotion for another couple of hundred meters before collapsing again, this time smacking his head against a metal railing and staying down. After an unforgivably long delay, medics came to Callum’s aid, ending his race officially. When he came to later in the back of an ambulance, the young runner croaked out words expressing his only concern: “Did I win?”

In a recent podcast interview, I was asked whether I thought mental fitness was something people were born with (or not) or something that could be developed over time. I was thinking of Callum Hawkins when I answered that I’d be lying if I said that mental fitness was not partly innate. Exertional heat illness had reduced Callum to a beast of basic instincts in the crisis phase of his 2018 Commonwealth Games Marathon performance. He most certainly was not making considered tactical decisions when he kept running well beyond the point where most runners would have quit, or when he got up and kept running after his first fall, or when he refused medical assistance initially after his second fall. Heck, he doesn’t even remember doing these things! He just did them.

Even more revealing is that moment in the back of the ambulance. Not yet out of danger and barely coherent enough for speech, he asked not “What’s wrong with me?” or “Am I going to be okay?” but “Did I win?” There’s something almost Shakespearean about the scene I picture when I read accounts of this moment. Rarely do so few words say so much about a person. Thank goodness people like Callum Hawkins exist.

As for the rest of us, we just need to accept that Callum and athletes like him have something we lack and can never acquire. But that’s okay. The answer to the nature/nurture question is seldom either/or, and mental fitness is clearly something that any athlete can cultivate over time, even if the very highest level of mental fitness is attainable only by those who are born with this potential. In this respect, mental fitness is very much like physical fitness.

We all know that only a tiny percentage of the human population possesses the genetic potential to reach the elite level of endurance sports performance. But this knowledge does not make the rest of us throw up our hands and say, “What’s the point?” That’s because even the least talented among us has the capacity to increase our endurance fitness markedly through training, and there is tremendous satisfaction to be had in earning such improvement.

It’s the same with mental fitness. I myself was born with a very low level of mental fitness, as evidenced by the various stunts I pulled to escape the pain cave as a high school runner—faking an injury in the middle of a 2-mile track race, hiding in the woods, and missing the start of another 2-mile track race, etc. But years of consciously working to raise my mental game transformed me into a completely different athlete, one who is utterly fearless on the racecourse. I can’t see myself ever waking up in an ambulance and asking “Did I win?”, but I’m okay with that, just as I’m okay with not being able to attain a VO2max of 80 ml/kg/min.

No matter what your starting point is with mental fitness, accept it and focus on getting better.

“We can neither deny what science affirms nor affirm what science denies.” I forget who said this, but whoever said it, it’s true. If you’re not so sure about that, it’s likely because you’re misinterpreting the statement as meaning that science is always right about everything. But that’s not at all what it says. What it says is that if you want to be “right” about anything, you must use the scientific method to address whatever it is you want to be right about. For example, if the scientific method is used to arrive at the conclusion that earth’s climate is changing, and that human activity is the primary driver of that change, then no one should put any stock in a denial of this conclusion unless it, too, is arrived at through the use of the scientific method. Even if it turns out that earth’s climate is not changing or that human activity is not the primary driver of that change, a person whose reason for denying the current scientific consensus on this matter is that it snowed in April one time last year is not really “right,” or is right only in the sense that the stopped clock is right twice a day. Indeed, the only way it could really “turn out” that earth’s climate is not changing or that human activity is not the cause of that change is for science itself to come to this new conclusion.

The scientific method is really nothing more, and nothing less, than intellectual integrity. By nature, individual human beings tend to form highly biased beliefs. A highly biased belief can be true, but in general, biased beliefs are unreliable. The scientific method was developed as a way to remove bias from the process of belief formation as much as possible. It is by no means a perfectly reliable method of forming beliefs, but it is more reliable than any other method.

Granted, the applicability of the scientific method is limited. It cannot be used to settle questions such as whether the Beatles are better than the Rolling Stones or whether prisoners should be allowed to vote—in other words, aesthetic or moral questions. Science is also of limited value in the domain of real-world problem solving. For example, I’d put more trust in an experienced general with a record of winning battles to win the next battle than in a scientist who came up with a new strategy for winning battles by running a bunch of computer simulations.

Endurance sports training is another example. Historically, elite coaches and athletes have been way out ahead of the scientists with respect to identifying the methods that do and don’t work. The crucible of international competition is not a controlled study, but it’s enough like one in its ruthless determination of winners and losers to have given lower-level coaches and athletes like me a high degree of confidence in their beliefs about the best way to train. In contrast, it’s actually surprisingly difficult to design and execute a controlled scientific study that has any substantive relevance to real-world endurance training. For example, one of the greatest certainties of endurance training is that high-volume training is essential to maximizing fitness and performance, yet there is virtually zero scientific evidence to support this certainty because it’s impractical to execute the kind of strictly controlled, long-term prospective study needed to supply such evidence.

But things are changing. The advent of wearable devices has made it possible for sport scientists to take a “big data” approach to investigating what works and what doesn’t in endurance training. In this approach, scientists dispense with the familiar tools of generating hypotheses and then testing them by actively intervening in the training of a small group of athletes and instead just collect relevant data from very large numbers of athletes and use statistical tools to quantify correlations between particular inputs (e.g., training volume) and specific outputs (e.g., marathon performance). While this approach lacks the tidiness of the traditional controlled study, it has the potential to yield results that have equal empirical validity by virtue of the sheer volume of data involved. And because these studies are done in situ, they do not share the controlled prospective study’s questionable real-world relevance.

The Science of Running

As an experienced endurance coach who respects science, I have long been highly circumspect in using science to inform my coaching practices. I always check new science against what I know from real-world experience before I incorporate it into my coaching practice. But studies based on the big-data approach are my kind of science because they’re really just a formalized version of the learning we coaches do in the real world.

So I was particularly excited to see a new study titled “Human Running Performance from Real-World Big Data” in the journal Nature. It’s a true landmark investigation, drawing observations from data representing 1.6 million exercise sessions completed by roughly 14,000 individuals. Its authors, Thorsten Emig of Paris-Saclay University and Jussi Peltonen of the Polar Corporation, are clearly very smart guys who understand both statistics and running. The paper is highly readable even for laypersons like myself, and it’s also available free online, so I won’t belabor its finer points here. What I will say is that its three key findings squarely corroborate the conclusions that elite coaches and athletes have come to heuristically over the past 150 years of trying stuff. Here they are:

Key Finding #1 – Running More Is the Best Way to Run Faster

One of the key variables in the performance model developed by Emig and Peltonen is speed at maximal aerobic power (roughly equivalent to velocity at VO2max), which they are able to “extract” from race performance data. The collaborators found that the strongest training predictor of this variable was mileage. Simply put, runners who ran more were fitter and raced faster. Emig and Peltonen speculated that high-mileage training achieved this effect principally by improving running economy.

Key Finding #2 – There Is No Such Thing As Too Slow in Easy Runs

Another clear pattern in the data collected by Emig and Peltonen was that runners with a higher MAP speed tended to spend more time training at lower percentages of this speed. In other words, faster runners tended to train slower relative to their ability. As an example, the collaborators tell us that a runner with a MAP speed of 4 meters per second (6:42/mile) will do most of their training between 64 and 84 percent of this speed, whereas a runner with a MAP of 5 meters per second (5:21/mile) will cap their easy runs at 66 percent of this speed. Here we have clear validation of the 80/20 rule of intensity balance, which I always like to see.

Key Finding #3 – Training Load Is Not the Gift That Keeps on Giving

Perhaps the “freshest” key finding of this study is one that validates the practice of training in macrocycles not exceeding several months in length. What Emig and Peltonen discovered on this front was that individual runners appeared to have an optimal cumulative training load representing the accumulated seasonal volume and intensity of training that yielded maximal fitness and performance. Runners gained fitness in linear fashion as the season unfolded and as they approached this total, but when they went beyond it, their fitness regressed. In short, training is not the gift that keeps on giving. Runners can train only so much and get only so fit before they need a break.

That’s science.

Something is wrong with my body. I don’t have a diagnosis yet, but I think I might be iron deficient. Other possibilities are burnout, a low-grade viral infection, low blood pressure, stress, and vitamin D deficiency. What I know for certain is that I feel terrible when I exercise, and particularly when I run.

I began to suspect something was amiss a couple of weeks ago, when I gave a subjective rating of “Poor” to a string of runs recorded in my online training log. I wasn’t yet performing much below standard at that point, but I didn’t feel as good as I normally do when running. The following week, though, I was forced to abandon consecutive high-intensity interval runs—something I hadn’t done in as long as I can remember, perhaps never. Both times my body just didn’t have it.

Things went south from there. Although I continued to feel fine at rest, I decided that I needed to take a break from intense exercise while I tried to figure out what was going on. My plan for my next easy run was to coast along at a pace that felt comfortable, no matter how slow it was. That pace turned out to be 8:40 per mile, or well over a minute per mile slower than my usual pace in easy runs. What’s more, my heart rate hovered around 160 bpm at that pace, whereas typically it’s in the low 130’s at 7:00 per mile. Time to panic!

Not really. I’m very slow to panic. But it was time to course correct, and specifically to eliminate all high-intensity efforts from my training and to reduce my run frequency from every day to every other day (while continuing to do some form of exercise twice daily, not including the two-mile walk I do with my wife each morning) until I’d identified and addressed the cause of my indisposition. In other words, I went into a kind of holding pattern in my training, similar to when I shift into maintenance mode after completing a big race and before starting to ramp up for the next one

Coincidentally, the very next day after I made this decision, I stumbled across a study newly published in Frontiers in Physiology that was highly relevant to my situation. An international research team led by Nicki Winfield Almquist of Inland Norway University of Applied Science investigated the effects of including a single session of sprint intervals in the off-season training of elite male cyclists. Sixteen cyclists were separated into two groups. For a period of three weeks immediately following the conclusion of a competitive season, both groups reduced their overall training volume by 60 percent, but whereas one group did all of their cycling at low intensity, the other group swapped out one weekly easy ride for a session that included three sets of three 30-second sprints.

Almquist’s team was interested not only in how the sprints would affect the cyclists’ fitness but also in how it would affect them psychologically, as mental recovery is a major objective of off-season training. If the sprints benefited the athletes’ fitness at the cost of compromising the recharging of their emotional batteries, then using the method in off-season training would not be advisable. But that’s not what happened. Testing conduced at the conclusion of the three-week intervention revealed that the sprint group performed better in sprints, as would be expected, and also exhibited smaller declines in 20-minute time trial performance and fractional utilization of VO2max compared to the control group while recording similar scores in a standardized Athlete Burnout Questionnaire.

One thing I noticed during the first bike ride I did after deciding to switch into maintenance-training mode was that I didn’t feel any worse climbing up the lone hill in my neighborhood than I did noodling around on the flats. Thus, after reading this study, I decided to insert some 30-second hill sprints into my next ride. Granted, this wasn’t exactly the use that Almquist et al had in mind for the method, but I survived the sprints just fine and, if nothing else, doing them made me feel a bit better about my situation—that I was doing one more thing to limit its impact on my fitness.

The next time you find yourself in maintenance training mode, try throwing some sprints into the mix. Again, the cyclists in the study I described did just nine, 30-second sprints once a week. Far from interfering with your need to get away from hardcore workout suffering for a few weeks, these sprints may in fact become something you look forward to on Tuesdays (or whenever you choose to do them), much as I am looking forward to my next sprint set.

By the way: You will no doubt be infinitely relieved to hear that, since I started writing this post a few days ago, I’ve begun to feel better, and I think I’ve identified the culprit behind my bad patch, but that’s a topic for another day. . .

Recently I created a custom training plan for an Italian ultraendurance cyclist who was preparing for a pair of multiday, multi-thousand-kilometer bike tours, and who told me in the onboarding questionnaire he submitted that increasing his functional threshold power (FTP) had been a major point of emphasis in his training.

For the runners in the room, FTP is intended to serve as a proxy marker of lactate threshold intensity on the bike. It is, by definition, the highest power output a cyclist can sustain for one hour (this being the average amount of time a trained cyclist can sustain lactate threshold intensity in a laboratory setting) and is determined through a 20-minute time trial, where the average wattage sustained in this test is multiplied by 0.95 to arrive at a final result.

Again for the runners in the room, an FTP test is essentially the equivalent of a 5K running time trial, which takes 20 minutes to complete, give or take. So, tell me: If you were training for a seven-day running event that would cover many hundreds of miles in total, how concerned would you be about lowering your 5K time?

It’s not that FTP is completely irrelevant to the kind of fitness needed to excel in a multiday event. It’s just that other things are more relevant, and therefore treating FTP increase as a point of emphasis amounts to taking your eye of the ball. But I’ll go even further and say that obsessing over FTP increase is a counterproductive distraction if you’re training for anything other than an FTP test. In fact, even if you are training for an FTP test, increasing your FTP should not be your top priority throughout the process.

That FTP has become the standard measure of cycling fitness is more a matter of historical accident and exigency than any intrinsic superiority of FTP relative to other measures. Research has shown that various tests and measures, including ventilatory threshold, respiratory compensation point, respiratory exchange ratio, maximal lactate steady state, maximum power in a graded exercise test, power-to-weight ratio, and VO2max are about as good at predicting real-world cycling performance. The only reason FTP rather than any of these other things is the bright, shiny object that cyclists and triathletes can’t seem to take their eyes off is that the other things aren’t as practical outside of the exercise lab.

The same principle holds for any test or metric you might use to measure fitness or a component thereof in the training process. Among athletes there is an unfortunate propensity to seek continuous improvement in any test or measurement you put in front of them, no matter how tangential it is to the specific type of fitness they need in order to excel on race day. I’ve seen athletes sabotage their own progress by overemphasizing everything from VO2max to body weight to barbell squat performance.

I get it. If a given metric is performance-relevant, it’s easy to assume that improving that metric will always translate to better performance on the race course. But it doesn’t work that way, because there’s no such thing as general fitness. Each event demands a very specific type of fitness, and the goal of training is to be good at that, not good at every conceivable proxy. For example, if your VO2max is increasing in the late stages of training for an ultramarathon, it’s likely because you’re not doing the necessary training to increase your respiratory exchange ratio, which has greater relevance to ultramarathon performance.

The time to see your VO2max increasing in training for any event that is likely to take more than an hour to complete is early in the process, before you shift your focus to more race-specific fitness priorities. In fact, if you’re a more experienced athlete, you could successfully gain in the type of fitness you really need for a particular event without seeing any change in your aerobic capacity. The typical elite endurance athlete attains a lifetime peak in VO2max in their early 20s, and then continues to improve on the race course for another decade. Kellyn Taylor, my former honorary teammate on HOKA Northern Arizona Elite, recently set a 10,000m PR of 31:07 at age 34. It’s very likely her VO2max was higher at 24.

There are some things you might measure in the training process that, in some cases, should decline in the late stages of preparing for a race. Examples:

  • If your sit-and-reach performance (i.e., hamstrings flexibility) declines ahead of any running race, that loss of flexibility indicates that your “leg stiffness” is increasing and your running economy improving, which is a good thing.
  • A 2004 study by researchers at Ball State University found that the calf muscles of college cross country runners got weaker and smaller over the course of a competitive season, which sounds bad, but the muscles actually shrank more than they weakened, which means they actually got stronger relative to their size, which is a good thing for a distance runner.
  • Similarly, when I was training for Ironman Santa Rosa in 2019, my anaerobic capacity decreased in parallel with gains I made in aerobic fitness and endurance, which was good for my Ironman performance prospects.

It is useful and all but unavoidable to measure things during the training process. But it’s important to maintain perspective on the numbers as you go. The goal is not to get better at everything all the time. The goal is to maximize race-specific fitness on race day. Achieving this goal will require that you prioritize different components of fitness in the proper order and that you hold steady in certain metrics and be content to go backward in certain others in some periods. In short, govern the metrics, don’t let the metrics govern you.

These are exciting times to be an endurance training geek. We seem to have entered a new period in which exercise scientists are taking the lead in coming up with innovative new workout formats. It makes sense. For many decades, humanity knew so little about how to train optimally for endurance performance that the majority of innovations simply had to come from folks in the trenches—namely coaches and athletes—throwing stuff against the wall and seeing what stuck. The role of scientists was to come along afterward and confirm that what seemed to work best in the real world really did, and to explain why.

In the past several decades, however, the pace of innovation has slowed greatly, a sure sign that we’ve gotten pretty close to the point where training methods cannot be improved any further. Being close to this point is not the same thing as being at this point, however. There’s still room to innovate, but it’s more a matter of fine-tuning now; the days of radical tacking are gone for good. A different sort of expertise is required for this task—a sort that scientists are showing themselves to be well suited for.

Specifically, exercise scientists have lately been using their knowledge of why some training methods work better than others to create workout formats that work better still. True to their nature as scientists, they are very focused on measurable fitness variables such as VO2max, Their way of innovating, therefore, is to in seek out ways to enhance he fitness benefits of training without simply making workouts harder. Most of the new workout formats I’ve seen in the past few months have been designed specifically to boost the amount of time an athlete spends above 90 percent of VO2max in an individual session—known to be an especially potent fitness-boosting stimulus—as compared to a traditionally formatted workout of equal workload and/or perceived difficulty.

The latest offering comes from a trio of researchers working at the University of Udine, Italy. Their idea was to design an interval session featuring high-intensity work bouts that steadily decreased in length throughout the session. The rationale behind this design, as noted in a study published in the European Journal of Applied Physiology, was that past research had shown that longer intervals at high intensity allow athletes to reach VO2max quickly, whereas short intervals allow them to continue longer before reaching exhaustion. Would a set of decreasing intervals offer the best of both worlds, comparing favorably to a set of long intervals and a set of short intervals in these respects?

To find out, the researchers had 12 cyclists complete the following three workouts:

Short Intervals Long Intervals Decreasing Intervals
0:30 @ high intensity/0:20 @ low intensity repeated to exhaustion 3:00 high/2:00 low repeated to exhaustion 3:00 high/2:00 low

2:00 high/1:20 low

1:00 high/0:40 low

0:45 high/0:30 low

0:30 high/0:20 low repeated to exhaustion


In all three workouts, the high-intensity efforts were performed at the highest power output each individual cyclist could sustain for 5 minutes and were repeated to exhaustion. Each subject completed all three workouts in random order on separate occasions. On average, the cyclists lasted 13 minutes and 20 seconds and spent 5 minutes and 12 seconds above 90 percent of VO2max in the decreasing intervals workout, compared to 11:54/3:02 in the short intervals workout and 11:04/2:59 in the long intervals workout.

The researchers concluded that “despite the higher stimulation of VO2, the rate of perceived exertion and the other physiological parameters at the end of the exercise were not different compared with long- or short-interval HIIT, suggesting that [the decreasing intervals format] was not more demanding. In light of the favorable or similar physiological and/or perceptual

responses to [decreasing intervals] compared to the other protocols and given the improved capability to prolong the time close to VO2 peak, it could be used as a preferable method to elicit similar or greater physiological adaptations.”

Sound like decreasing intervals are simply better, right? And if so, they should completely displace short- and long-interval VO2max sessions in the training process, right? Not so fast. As interesting as it is, this study falls far short of constituting a total contextual evaluation of these three interval formats. It’s important not to lose sight of the fact that doing five 3-minute intervals at your 5-minute maximum power is a different experience from doing decreasing intervals. The suck that you feel toward the end of the former is more similar to the suck you’re going to experience in races, and I think there’s a lot to be said for that. Therefore I have no intention of expunging traditional VO2max interval workout formats from the training I prescribe for the athletes I coach or for myself.

Still, I’m excited about decreasing intervals, and indeed I’ve already begun to prescribe them to athletes I coach and to practice them in my own training. They can be done either on a bike, as originally designed, or as a run. If you do them on a bike, complete the high-intensity intervals at 117 percent of the average power output you achieved in your most recent 20-minute FTP test. So, if your 20-minute power is 293 watts, do the high-intensity intervals at (293 x 1.17 =) 342 watts. If you choose to do decreasing intervals as a run, complete the high-intensity intervals at maximal aerobic speed (MAS), which is the fastest pace you could sustain for about 6 minutes.

Note that the subjects in the study I described performed decreasing intervals to the point of exhaustion solely for the sake of determining which of the three formats allowed them to continue the longest. When doing decreasing intervals as a part of your normal training, you may want to stop short of exhaustion. Specifically, I suggest you complete the sequence just once on your first try to get a feel for it. If you’re game for a tougher challenge, the next time you do decreasing intervals, go back to the top of the sequence immediately after the 20-second recovery and continue until you can no longer hold power on the bike or until you’ve “had enough,” if you’re running. On average, the study participants were able to complete only one full circuit plus part of a second 3-minute effort, so don’t expect the fun/suffering to last too terribly long.

In last week’s post, I addressed a fundamental question: What are the major objectives of an endurance athlete’s diet? In this post I would like to tackle an even more basic question, which I’ve already given away in the title. Namely: Which is most important for endurance fitness and performance—training, diet, or sleep?

As you’re about to see, there’s no simple answer to this question. But attempting to answer it is nevertheless a worthwhile exercise, because it yields clarity on the role of each of these three factors in relation to your athletic ambitions.

The All-or-Nothing Angle

Sleep is a mysterious phenomenon that has long eluded scientists’ efforts to fully explain it. As neuroscientist Michael Halassa confessed in a 2017 article published on livescience.com, “It’s sort of embarrassing. It’s obvious why we need to eat, for example, and reproduce . . . but it’s not clear why we need to sleep at all.” What isclear is that we literally can’t live without sleep. The longest any human has been known to survive without sleep is just 11 days.

Arguably, this makes sleep even more important than food. The average person can go about 40 days without eating before succumbing to starvation. 

As for training (i.e., exercise), it is, of course, not required for survival, though a case can be made that some amount of physical activity is needed to achieve a normal lifespan, as people who are unable to move their bodies (i.e., sufferers of paralysis) don’t live as long as people who are.

In light of these facts, we can say definitively that if you were going to attempt to complete an endurance race either without training, without eating, or without sleeping, your best move would be to skip the training in favor of eating and sleeping.

The Realistic Angle

Thankfully, you will never have to make the choice I just presented. We live in a relatively stable society in which most people have plenty of food to eat and a comfortable bed to sleep in. So, let’s now approach the question of whether training, diet, or sleep is most important for endurance fitness and performance from a more realistic angle. 

Although I just got through saying that in our society most people have a comfortable bed to sleep in, the modern lifestyle is such that a large fraction of us do not spend enough time in bed and do not get enough sleep. Research suggests that the kind of chronic, mild sleep deprivation that is so common in our society has a bad effect on endurance performance. A 2016 study by researchers at UC San Francisco, for example, found that cyclists whose sleep was restricted to four hours per night for three nights experienced a 2.9 percent decrease in maximal aerobic power and a 10.7 percent decrease in time to exhaustion at VO2max. True, few athletes get only four hours of sleep per night as a matter of habit, but it’s reasonable to assume that longer periods of milder sleep deprivation probably have a similar effect.

Similarly, although most athletes get enough to eat overall, a majority of athletes also fall well short of eating optimally to support their fitness and performance. Common mistakes include poor diet quality, overeating, and within-day energy deficiencies, all of which are proven to negatively affect endurance fitness and performance.

And then there’s training. What’s different about training, from the realistic perspective, is that, whereas everyone sleeps and eats, only a minority of adults in our society exercise regularly. This makes the transition from sedentariness to endurance training a rather common phenomenon. Thus, in the case of training, the realistic scenario isn’t all that different from the all-or-nothing scenario.

There’s plenty of research on how the transition from sedentariness to endurance training affects endurance performance. One example is a 2019 study by Spanish and German researchers, which found that 12 weeks of endurance training increased VO2max by 11 percent and time to exhaustion by 14 percent in a group of previously sedentary adults. Those are big numbers. And it should be noted that sedentary individuals can’t exactly leap straight into heavy training workloads right off the couch. The subjects in this study completed just three low-intensity sessions per week totaling 2.5 hours. Given what we know about the dose-response relationship between endurance training and fitness and performance, it’s safe to say that these folks would have experienced vastly greater improvements over time if they had continued to train in a progressive manner.

Indeed, studies investigating the effects of different training programs in already-fit athletes show tremendous potential for improvement in going from imperfect training to optimized training. A 2014 study conducted at Salzburg Universityreported improvements ranging from 6.2 percent and 17.4 percent in time to exhaustion among experienced endurance athletes placed on one of four different training programs for nine weeks.

Comparing the above-referenced data on sleep, diet, and training leads us to the conclusion that, in the realistic scenario, training offers far greater potential for improvement in endurance fitness and performance than does either sleep or diet. In other words, if you are a typical athlete who doesn’t get quite enough sleep, has a mediocre diet, and trains less than optimally, and you can only change one of these things, your best move is to optimize your training.

The Bottom Line

So, which is most important: diet, sleep, or training? The answer, we now see, is that training, on the one hand, and diet and sleep, on the other hand, are important in different ways. Most athletes place greater emphasis on training, and they are right to do so in the sense that, realistically, getting the training piece right will have a greater impact than getting either the diet or the sleep piece right.

However, as we saw in exploring the all-or-nothing angle, diet and sleep are more foundational than training. Fitness is really just an extension of health, and diet and sleep are more important to basic health than training is. Therefore, any athlete who wishes to get the most out of optimized training should make every effort to get the diet and sleep pieces right as well.

I am not an exercise scientist, but I do have a strong interest in the science of endurance exercise, and every once in a while I speculate on the kinds of questions exercise scientists like to explore experimentally. For example, back in 2004 I found myself wondering if training in a hot environment might improve endurance performance in a temperate environment, sort of like how training at high altitude improves endurance performance at low altitude. My curiosity led me to put the question to famed sports science researcher Tim Noakes, who, in his prompt and courteous reply, dismissed the idea as “too bizarre to consider.”

Six years later, sweet vindication came my way in the form of a study appearing in the Journal of Applied Physiology under the title “Heat acclimation improves exercise performance.”

Led by Santiago Lorenzo of the University of Oregon, the study involved 20 highly trained cyclists, who were asked to complete a performance test in temperate conditions on two occasions separated by 10 days. Between the tests, all 20 cyclists completed a prescribed training program, but 12 of them did it in a controlled, hot environment (100 degrees Fahrenheit) while the other eight performed their workouts in the same temperate conditions (55 degrees) as the performance tests. The 12 cyclists who underwent heat acclimatization improved their performance in the temperate performance test by a massive 7 percent, while the control group showed no improvement.

Lorenzo’s team attributed the performance-boosting effects of heat acclimatization on endurance performance in cool conditions to improved efficiency in heat dissipation and increased blood volume. They also found evidence that it caused some changes in muscle cell enzymes, which may have contributed to the effect as well.

Several subsequent studies have mined the same vein vein more deeply. The most recent study on heat training in endurance athletes, published in the European Journal of Applied Physiology, offers important guidance on how best to use this method in real-world settings. Led by Mark Waldron of Swansea University, the experiment aimed to track the time course of adaptations to heat training.

Twenty-two male cyclists were separated into experimental and control groups. Members of the experimental group cycled indoors at 100 degrees Fahrenheit while members of the control group did an equal amount of cycling at 68 degrees. Waldron’s team measured VO2max in both groups before the intervention, on days five and ten of the intervention, and on days one, two, three, four, five, and ten afterward.

The results are interesting. Both groups exhibited an initial decrease in VO2max during the 10-day training period that was followed by a rebound beyond baseline afterward. The peak increase was higher in the heat-training group, but not until four days after the last heat-training session, with some variation between individuals. VO2max then began to trend toward decline in this group, though the amount of decline that occurred between day four to day 10 post-acclimation did not reach statistical significance.

In a nutshell, these findings suggest that if you’re going to use heat training to increase your endurance performance, you need to time it to end about four days before you race. This means that your heat training is likely to overlap with your pre-race taper. Is this insane? It might sound so, but there’s a difference between sound and substance. While training in 100-degree heat might be uncomfortable, it’s not going to kill you, and which would you rather do: 10 days of heavy, peak training in 100-degree heat or 10 days of lighter, taper training?

That being said, I don’t recommend that you try heat training for the first time before an important race. Instead, test it out early in a training cycle to see how it affects you. It won’t be wasted even then, because if it works it will give your subsequent training a nice boost.

I can’t help but wonder if doing one hot workout every week or so throughout a training cycle might have similar benefits. Personally, I would find this approach easier to manage. Heat training could then be used in much the same way carb-fasted workouts are, and perhaps the two methods could even be combined to minimize the number of training days that need to be set aside as “special” sessions. Can I get a real exercise scientist to look into this?

As part of my ongoing quest to qualify for the Ironman World Championship, I am working with a company called INSCYD (pronounced “inside”), creators of a physiological performance software tool that helps endurance athletes like me identify specific ways to improve their fitness.

A few weeks ago I performed a sequence of bike tests that are used to generate the data that the program uses to assess cycling fitness/performance. They were pretty tough, comprising a 20-minute time trial that I had to start with a 60- to 90-second all-out effort, a four-minute time trial starting the same way, and a handful of seated 15-second sprints in a high gear ratio. What’s special about INSCYD is that it uses performance data not only to measure performance variables such as anaerobic threshold power but also to estimate physiological variables such as VO2max with an impressive degree of accuracy.

My results seemed spot-on to me. According to INSCYD, my VO2max, or aerobic capacity, is 62 ml/min/kg (about average for an athlete of my performance level and age), my VLamax, or anaerobic capacity, is 0.23 mmol/l/s (extremely low, which is actually good for an athlete in Ironman training), and my weight-adjusted anaerobic threshold power is 4.5 watts/kg (extremely high). All of this was explained to me by INSCYD’s Greg Hillson when we went over the results over the phone. Greg further explained to me that, based on these results, my best opportunity to increase my cycling performance ahead of Ironman Santa Rosa is to increase my VO2max.

Sounds great in theory, but the best most effective ways to increase aerobic capacity are to train a lot and to perform brutally hard high-intensity interval workouts on a regular basis, both of which things I was already doing before I was tested. Referring to these methods as low-hanging fruit, Greg suggested I look to some next-level ways of boosting aerobic capacity a bit, including a particular carbohydrate-restricted workout protocol that was shown to increase cycling efficiency, cycling time to exhaustion at peak aerobic power, and 10K run performance among triathletes in a 2017 study.

I gave it—or a version of it—a try recently. Normally I start my afternoon workout between one and two o’clock, but on this occasion I waited until four o’clock to do an indoor cycling workout containing four, eight-minute efforts at threshold power and lasting 80 minutes in total. After showering and changing, I ate a low-carb dinner of salmon, eggs, and a green salad with oil-based dressing. This ensured that I went to bed with reduced glycogen stores and woke up the next morning even more depleted.

On any other day I would have made breakfast my first order of business, but in obedience to the protocol I instead hopped on the treadmill and ran for one hour at an easy pace. Done by 6:30 am, I then enjoyed a high-carb breakfast (whole-grain, low-sugar cereal with whole milk and fresh raspberries, orange juice, and black coffee).

I now have super powers. Just kidding. I won’t know what effect these sessions have had (and I plan to do one per week from here on) until I repeat the INSCYD tests between two and a half and three weeks before race day. But I trust the science and there’s really no risk. While you might expect a fasted morning workout to be rather miserable after a one-two punch of hard intervals and carbohydrate restriction the evening before, I felt completely normal.

Another next-level method of nudging aerobic capacity upward that Greg Hillson recommend I try is sauna training. And I’m totally game, but that’s a topic for another time. . .

Every endurance athlete is familiar with the idea that certain physiological tests can be used to predict endurance performance. For example, the classic VO2max test is a very reliable way to assess how well an athlete is likely to do in a race or time trial. Other examples are the Wingate test and a simple maximal velocity test.

Increasingly, though, scientists are recognizing that certain psychological tests are also strong predictors of endurance performance potential. Collectively, recent studies in this hot area of research are showing that the mind is not merely a passenger in races and tough workouts but an active contributor to performance. Among the mental attributes that have been positively linked to endurance performance are pain tolerance, emotional intelligence, self-efficacy and inhibitory control. Let’s take a closer look at each.

Mental Attributes

Pain Tolerance

Scientific evidence that a high tolerance for physical pain aids endurance performance goes all the way back to 1981. That year, in the British Medical Journal, Stirling University psychologists Karel Gisbers and Vivien Scott reported finding that pain tolerance was higher in elite swimmers than in club swimmers and higher in club swimmers than in noncompetitive swimmers.

Fortunately, pain tolerance is trainable. Gisbers and Scott found that pain tolerance increased in their subjects over the course of a season. And in a 2017 study, British researchers found that whereas a high-intensity training program and a moderate-intensity training program increase aerobic fitness equally in a population of healthy nonathletes, the high-intensity program increased cycling time trial performance by a greater amount, an advantage that was linked to a larger increase in pain tolerance.

Emotional Intelligence

According to Psychology Today, “emotional intelligence is the ability to identify and manage your own emotions and the emotions of others.” Like all human traits, this one exists on a spectrum. Some people have low emotional intelligence, others high, while most fall somewhere in the middle. Psychologists use standardized tests to assess the emotional intelligence, and the results are highly correlated with real-life outcomes. Studies have shown, for example, that men and women who test high for EI tend to be more successful in their careers and are less likely to get divorced.

And guess what? A recent study by Italian researchers found that emotional intelligence was highly predictive of half-marathon performance in a group of 237 recreational runners. In fact, EI scores were more closely correlated with finish times than training variables were. It makes sense, right? Endurance racing presents an intense emotional challenge. It’s only to be expected that athletes who are well able to identify and manage their emotions will race more successfully.


Self-efficacy is a general belief in one’s ability to achieve goals. Whereas all of us tend to have a high degree of task-specific self-efficacy for things we’re good at, some people have an above-average belief in their capacity to achieve all kinds of goals, and according to a new study by French researchers, these individuals make better endurance athletes.

The subjects were 221 participants in an ultramarathon. Before the race, they all “completed a survey that included measures of: (a) motivational variables (self-determined motivation, basic needs satisfaction, achievement goals), (b) theory of planned behavior constructs (attitudes, subjective norms, self-efficacy and intention to finish the race), and (c) coping strategies in sport.” After the race, the researchers found that the runners who scored highest for self-efficacy were least like to drop out.

Inhibitory Control

Psychologists use the term inhibitory control to denote the ability to override impulses and stay focused on a goal. Inhibitory control comes into play anytime you want two or more contradictory things simultaneously and have to choose which one you want more. During races, athletes experience a conflict between the desire to reach the finish line as quickly as possible and the desire to spare themselves the discomfort that comes with pushing for maximum performance.

And guess who else scores well on these tests? High-performing endurance athletes. In a 2015 study, Italian researchers found that faster runners significantly outperformed slower runners in a standard test of inhibitory control, and the following year a different team of researchers reported a similar finding in cyclists.

Want to be a better endurance athlete? Work on your pain tolerance, emotional intelligence, self-efficacy, and inhibitory control. And, oh yeah, your VO2max.

We live in a highly individualistic society, a situation that has both pluses and minuses. On the plus side, our children tend to grow up with a sense of freedom to choose their own path in life. On the minus side, a growing percentage of us are burdened by feelings of loneliness and isolation that make us unhappy and have proven consequences for our physical health.

As an endurance coach and nutritionist, I see our society’s hyperindividualism manifest in a sense of exaggerated specialness and uniqueness. Take the “I can’t eat that” phenomenon, for example. Although food allergies, intolerances, and sensitivities are real, these conditions are claimed far more often in some societies and groups than in others—specifically in the most individualistic societies and groups. Asserting the need for a special diet is in many cases a way of asserting personal specialness.

Individualized approach to Endurance training

I see individuality overemphasized to some extent in the training realm too. In the 35 years I’ve been involved in endurance sports, I’ve observed a growing receptiveness to the notion that individual athletes training for the same event (e.g., a marathon) should do so in different ways based on genetic differences that affect how their bodies respond to various training stimuli. Contributing to this trend are studies such as one that was conducted by Canadian researchers and published on the online journal PLoS One in 2016, which found that when subjects were placed on an all-low-intensity exercise program for three weeks and, separately, on an all-high-intensity exercise program during a second three-week period, some subjects exhibited improved fitness only after the former and others only after the later, while only a few improved on both programs and no subject failed to improve on both.

Should we conclude from such findings that individual athletes should indeed take radically different approaches to training for races? I think not. The problem with a radically individualized approach to endurance training is that in essence it amounts to training for what you’re good at rather than training to be good at the specific event for which you are preparing. To return to our earlier example, a marathon is a very long race undertaken at a low to moderate intensity. No matter what your genetic makeup is, you won’t be optimally prepared to run a marathon unless your training features lots of running and frequent prolonged efforts at low to moderate intensity. Training for a marathon with a heavy emphasis on short, high-intensity intervals because you happen to be highly responsive to this type of training is only slightly less absurd than training for a marathon exclusively by chopping wood because testing has demonstrated that you are most responsive to this type of training.

But wait: If your body simply doesn’t adapt to low-intensity exercise, as the above-mentioned study suggests is the case for some individuals, then what benefit can these folks get from this type of training even if it is a marathon they’re preparing for? Good question, the answer to which is that of course every athlete really is capable of adapting to high-volume low-intensity exercise. The Canadian study cited above measured a few select variables such as VO2max and lactate threshold. But a marathon is not a VO2max test. So-called non-responders to low-intensity exercise who do not experience an increase in VO2max in response to this type of training but who do a bunch of it any way will undergo a host of other adaptations, including increased fat-burning ability and heightened resistance to impact-related muscle damage, that are crucial to marathon performance.

This is to say nothing of the neural and psychological adaptations. A runner who routinely does long training runs at low to moderate intensity will see improvements in central fatigue resistance and inhibitory control that he couldn’t gain any other way. Physiology aside, the experience of going long is an essential contributor to the capacity to go long.

The same principle holds for supposed non-responders to high-intensity exercise. A runner of this type who includes a small amount of high-intensity exercise in his training despite deriving no boost in aerobic capacity from it is sure to come away with other benefits, such as increased perceived effort tolerance, that will translate into better performance in real-world competition.

I don’t want to overstate my case. It is undeniably true that each athlete is unique and responds somewhat differently than do other athletes to the same training stimuli. But this individuality is itself overstated in some quarters, and again, even to the extent that athletes are different they must consider the specific demands of the event they’re preparing for before they consider their particular athletic type in deciding how to train.

The proper way to individualize training, therefore, is not to start from scratch with each athlete, inventing from whole cloth the method that is uniquely optimal for that individual. Rather, all athletes should begin by training with the methods that have proved most effective with athletes generally (80/20, etc.) and then fine-tune their formula based on how their body responds to these methods. And fine-tuning never means replacing running with chopping wood.

Most runners target a single intensity in all of their workouts. Either it’s an easy run or long run at a slow and steady pace or a tempo run with an effort at lactate threshold intensity sandwiched between a warm-up and a cool-down or an interval session featuring a set of a certain number of repetitions of uniform length or duration all done at the same high intensity or—you get the idea. But there is something to be said for doing the occasional workout that includes a range of different intensities.

First of all, multi-pace workouts are a literal change of pace, and as such they’re an effective way to keep your training fun and interesting. Multi-pace workouts are also a good way to get appropriate doses of different intensities. For example, if you’re at a point in your training where you can benefit from a little work at VO2max intensity—but only a little—why set aside an entire workout for it when you can incorporate that work into a session focused on an intensity you need more of—say, lactate threshold intensity?

Yet another benefit of multi-pace workouts is that they help teach effective pacing. Can you shift accurately from half-marathon pace to 10K pace to 5K pace by feel? Most runners can’t, but runners who do workouts that include efforts at all three of these paces can. Finally, multi-pace workouts that put the fastest work at the end develop the capacity to dig deep and finish strong in races.

Here are three multi-pace workouts to try:

3 Multi-pace workouts to try

Intervals + Time Trial

This type of workout serves most of the purposes mentioned above. The interval segment provides the primary training stimulus and it should target a high aerobic intensity close to the lactate threshold. The closing time trial should be fairly short in order to serve the purpose of providing a modest exposure to VO2max and to get you suffering a bit. As a whole, an Intervals + Time Trial workout is very taxing and you shouldn’t attempt them very often. The specific session described below is one I did with NAZ Elite during my time in Flagstaff.

1-3 miles of easy jogging

Drills and strides

7 x 1 km @ lactate threshold pace with 1:00 standing recoveries (2:00 after the last rep)

1500-meter time trial

1-3 miles of easy jogging

30-20-10 Run

A few years ago, a team of Danish researchers led by Jens Bangsbo set out to see if they could come up with a high-intensity interval workout that was more enjoyable than standard formats without being less effective. They tested a variety of designs before settling on one that fulfilled their hopes: the 30-20-10 Run. After learning about it, I gave it a try, made a couple of tweaks, and started incorporating the workout into the training plans I create for my clients. I like to schedule 30-20-10 runs during recovery weeks and during the final weeks of preparation for longer races as a way to expose athletes to a range of intensities without making them go to the well. This workout is also a great way to teach better pacing. Here’s the basic format:

1-3 miles of easy jogging

5 x 1:00 with the 30 seconds at marathon pace, the next 20 seconds at lactate threshold pace (i.e., the fastest pace you could hold for one hour), and the last 10 seconds at a relaxed sprint. No recovery—just cycle right into the next interval until you’ve completed all five.

Complete three cycles of five 30-20-10 intervals with 5 minutes of jogging after each.

1-3 miles of easy jogging

Tempo + Sprints

As a long-distance runner, you should sprint, but not a lot. Because any sprinting you do in a race is likely (one hopes) to occur at the very end of a race when you’re tired, it makes sense to sprint on tired legs in training. In the Tempo + Sprints workout, you will do just that.

1-3 miles of easy jogging

Drills and strides

20:00 at lactate threshold pace

2:00 standing recovery

8 x 200-meter relaxed sprints with recovery by feel (i.e., go again when you’re ready)

1-3 miles of easy jogging

$ubscribe and $ave!

  • Access to over 600 plans
  • Library of 5,000+ workouts
  • TrainingPeaks Premium
  • An 80/20 Endurance Book


30 day money back guarentee

For as little as $2.32 USD per week, 80/20 Endurance Subscribers receive:

  • 30-day Money Back Guarantee