What We Know About the Future of Endurance Training

One of my favorite quadrennial rituals is the serve-and-volley between articles arguing that progress in Olympic sports has ground to a halt and those—like the one I wrote in June—wondering how the heck athletes managed to defy our predictions and continue getting faster. Somehow we always manage to convince ourselves that we’ve picked all the low-hanging fruit, and the only way to get better in the future will be to change the rules or cheat.

That’s why the title of a recent article in the International Journal of Sports Physiology and Performance caught my attention: “The Evolution of World-Class Endurance Training: The Scientist’s View on Current and Future Trends.” It’s the “future” part that piqued my interest. An expert panel of 25 sports scientists who work with world-leading endurance athletes and coaches, wrangled by Øyvind Sandbakk and former Olympic cross-country skier Silvana Bucher Sandbakk, both of the Norwegian University of Science of Technology, peered into their crystal balls to predict why and how they think top athletes will keep getting faster.

The panel actually addressed two distinct questions. The first was on the key trends that have fueled progress in the past ten to 15 years; the second was on the trends that will drive progress in the next ten to 15 years. The answers to the first question are interesting to contrast with the ideas I discussed in my June article on why endurance runners have seemingly been tearing up the track over the past few years. The biggest factors, in my telling, have been the development of supershoes and improved pacing. I also considered other ideas like changes in training philosophy (such as Norwegian-style thresholds), better dissemination of training knowledge, and of course drugs.

Ask a bunch of sports scientists what they think, and you’d expect to get a slightly different slant. Most of the same ingredients are there (with the exception of drugs), but the emphasis is on science and technology. The three big drivers of development, they suggest, are more accessible scientific knowledge; better integration of knowledge from across multiple disciplines; and new technology.

These three underlying drivers, in turn, give rise to five specific trends:

Sport-Specific Demands

Gone are the days when the milers and marathoners trained together for most of the year. Instead, training and recovery are geared to the unique physiological, psychological, and tactical challenges of each event. Athletes don’t just eat as many carbs as possible; they tailor their intake to the demands of each day’s training or competition. Marathoners don’t just train to be fast and efficient; they train to be fast and efficient when their legs are already dead.

Competition Execution

I mentioned better pacing above, but I was mostly focused on the rise of pacers and pacing lights. The sports scientists argue that better data, in part thanks to wearable tech, has enabled athletes to learn more about their specific strengths and weaknesses in order to come up with better individual race plans.

More Training (or Not)

There was a bit of a split in the panel on this. Some thought that athletes are better because they’re training more than they used to. Others thought that athletes are getting better at identifying the sweet spot that maximizes their gains without pushing them into injury or overtraining. That’s the premise of Norwegian-style thresholds, but the broader principle is that better data and monitoring is allowing athletes to tiptoe a little closer to the precipice without falling off.

Improved Training Quality

How much training you do isn’t the only metric that matters. You should also be doing good workouts. What that means is tricky to nail down (and will be the topic of a forthcoming column), but one example is whether you successfully achieved your intended workout goals. Faster isn’t always better if you’re too tired for the next day’s workout.

Professionalized Lifestyle

The old-school approach is epitomized by a line usually attributed to Rod Dixon, the New Zealander who won an Olympic bronze over 1,500 meters in 1972 and also won the 1983 New York Marathon: “All I want to do is drink beer and train like an animal.” These days, as Olympics sports have professionalized, athletes are far more focused on recovery, nutrition, sleep, and mental health, which can both enhance performance and prolong careers. What the modern athlete really wants to do is maximize their heart-rate variability.

Let me acknowledge a bit of bait-and-switch here. I promised a glimpse into the future of endurance training, but so far we’re just talked about what got us to where we are today. That’s because the expert panel expects progress in the next ten to 15 years to be dominated by the continued evolution of current trends. We’ll get even more sport-specific, even better competition execution, and so on. However, they did pull out four distinct area where they expect to see especially big gains in the coming years:

Tech for Individualized Training

Yes, they mentioned artificial intelligence. A few years ago, I wrote about a four-stage framework for the use of wearable tech in sport: you go from descriptive to diagnostic to predictive to prescriptive. What stage we’ve reached so far depends on who you ask, but I’d guess the vast majority of athletes, even at the elite level, haven’t progressed past the diagnostic stage. That’s likely to change: with each passing year, we’re gathering more data, and gaining better tools to analyze it.

One example the expert panel mentions: recent work on non-invasively determining muscle fiber type, which can influence how you respond to a given training load. With more fine-grained information like this—and with AI—the training data you upload to Strava may begin revealing unique patterns that enable your coach to adjust your training plan and produce better results.

Heat, Altitude, and Nutrition

Training at altitude has become almost compulsory for any endurance athlete with world-class aspirations. But there’s still plenty of debate about how to get the most out of your altitude training block, and it’s reasonable to assume that we’ll be better at it in another decade. The same goes for heat training, which is essential if you’re competing in the heat and possibly beneficial even if you’re not. As for nutrition—well, the only prediction I’m 100 percent confident about is that we’ll still be arguing about nutrition in a few decades, but it’s possible that in the process we’ll have learned some useful things that make us faster.

Athlete-Equipment Interactions

This one’s not explained in great detail, but my interpretation is: “Wow, runners sure got a lot faster in the last few years thanks to the totally unforeseen advent of supershoes, so it’s possible that other equipment breakthroughs will do the same.” That’s most likely in equipment-focused sports like cross-country skiing and cycling, but we now know that it can happen in any sport.

Injury Prevention and Health

A big focus here is the recognition of Relative Energy Deficiency in Sport (RED-S), which can affect both men and women but has disproportionately impacted women. But there’s still huge potential for further gains in understanding other challenges faced by female athletes. Figuring out ACL injuries, for example, would be a great start. Wearable tech and big data might also play a role in identifying injury risks before they happen—though there’s still a big gap between predicting an injury and preventing one.

So should we bet on athletes a decade or two from now being faster than they are now? Probably. But just like the current situation, it’s not clear to me that we’ll know what we did right when we get there. Every time I start to get too enthusiastic about the performance-boosting power of new technology, I remember that a disproportionate share of the world’s greatest distance runners still come from East African countries where sports science isn’t a high priority. And if there’s one thing that I’ve taken away from the whole supershoe thing, it’s that when a performance aid really works, it’s very obvious. We can debate ketones and brain stimulation and heart-rate variability until we’re blue in the face, but that’s only because their effects remain invisible to the naked eye.

If we’re talking about world records, my pick for the biggest driver of progress is simply numbers. The more people who try a given sport, the more likely we are to stumble across the rare barrier-breaking Usain Bolts and Faith Kipyegons who walk among us. It’s when we zoom in to an individual athlete—or to ourselves—that I think the trends described by the expert panel become more significant. If I start training seriously for a marathon that will take place six months from now, how likely am I to make it to the start line fit, uninjured, and mentally ready to have my best day? The odds aren’t great. If sports science can crack that nut, or at least raise the odds a bit, I’ll call that a triumph.

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