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“Predictive processing” offers novel ways to think about sports psychology, the limits of endurance, and the urge to explore.

If you read popular science books about the brain, you might have encountered a new “grand theory” called predictive processing. If you haven’t yet, you will. Over the last two decades, it has gone from obscure idea to increasingly dominant paradigm. And it’s such a broad and all-encompassing theory that it seemingly has something to say about everything: how the brain works, why it’s structured the way it is, what that means for how we perceive the world—but also horror movies, mental health, cancer cells, and perhaps even endurance sports and adventure.

I’ve been trying to get my head around predictive processing for five or six years now. It can get complicated if you dig into the mathematical details. But I recently read a book called The Experience Machine: How Our Minds Predict and Shape Reality that does a good job of conveying the theory’s essence in an accessible way. It came out last year and is by Andy Clark, a cognitive philosopher at the University of Sussex who is one of the theory’s leading proponents. The book got me thinking about how predictive processing applies to some of the areas of science that I’m most interested in.

Here, then, is a very rough guide to predictive processing—still a speculative and unproven theory at this point, but an intriguing one—from the Sweat Science perspective.

Normally, we assume that you see the world as it is. Light bounces off the objects around you and into your eyes; the receptors in your eyes send signals to your brain; your brain makes sense of those incoming signals and concludes that, say, there’s a snake on the path. Predictive processing flips the script. Your brain starts by making a prediction of what it expects to see; it sends that prediction out toward your eyes, where the predictions are compared with incoming signals. If there’s any discrepancy between the outgoing predictions and the incoming signals, you update your predictions. Maybe it turns out that it’s a stick on the path, even though at first glance you could have sworn it was a snake.

This is actually a very old idea. It’s often attributed, in a basic form, to Hermann von Helmholtz, a nineteenth-century German scientist. Modern neuroscience pushes the idea farther and offers some clues that it’s true: for example, there are more neural connections leading from the brain to sensory organs like the eyes than there are carrying information from the senses back to the brain. Those outgoing signals are presumably carrying the brain’s predictions to the senses. What we see (and hear and smell and so on), in this picture, is basically a controlled hallucination that is periodically fact-checked by the senses.

What I find particularly intriguing about predictive processing is that there’s a deeper mathematical layer. A British scientist named Karl Friston, who pioneered several brain imaging techniques in the 1990s and is by several measures the most-cited neuroscientist ever, has proposed an idea called the free energy principle. All life, Friston argues, has an essential drive to minimize surprise—which is related to a mathematical quantity, borrowed from physics, called free energy—in order to ensure its continued survival. The resulting equations are beautiful but famously inscrutable. If you’re interested, the best introduction I’ve found is in a free e-book published in 2022 by Friston and two colleagues called Active Inference: The Free Energy Principle in Mind, Brain, and Behavior. The important point, though, is that these equations lead to the qualitative picture I described above, of the brain as a prediction machine.

In The Experience Machine, Clark lays out some examples of why this idea matters. Mental health conditions like depression and anxiety may relate to glitches in how the brain updates its predictions; the aesthetic chills you get from great art or horror movies may signal that we’ve encountered “critical new information that resolves important uncertainties”—a physiological “aha” moment. But what does all this tell us about endurance?

The athlete-related topic that Clark addresses most directly in his book is sports psychology. For example, he has a section on the power of self-affirmation, in which the positive words you say to yourself alter your brain’s predictions, which in turns alters your actions in performance-boosting ways. I’ve written a bunch of times about the effects of motivational self-talk on endurance. I’m fascinated by the evidence that it works, but struggle to reconcile it with my mechanistic understanding of how the body works. Predictive processing offers a new way of understanding the science of self-talk.

The key point is that our brains aren’t just predicting the present; they’re also simulating the future, to minimize unexpected surprises. If we expect to feel pain, fatigue, doubt, or even hunger, those predictions become self-fulfilling prophecies—just as, if you’re wandering through the rainforest, you’re more likely to mistake a stick for a snake than if you’re walking down Fifth Avenue. I remember, a decade ago, puzzling over the results of a study that fed people milkshakes and found that their appetite hormones responded differently depending on whether they were told it was an “indulgent” shake or a “sensible” one. How could appetite hormones respond to words? Through the predictions sent from the brain to the gut.

Clark has a long discussion of placebos, but the most unexpected suggestion he makes is a way of improving sports performance “in a rather sneaky manner.” One of the interesting facts about placebos is that the response can be trained. If you give a real, clinically effective drug to someone repeatedly, their brain will eventually begin predicting the response more and more strongly. During the Second World War, nurses who were running short of morphine sometimes injected saline instead; it turns out that, if the patients had been receiving morphine regularly, their bodies (and brains) responded to the saline injection in a similar way.

Clark proposes training an athlete with a drug that is banned in competition (like stimulants), then giving them a placebo version when they actually race. In theory, this should generate a stronger placebo response than you’d normally get. For the record, I don’t think this is consistent with what the World Anti-Doping Agency calls “the spirit of sport,” but it’s an interesting thought experiment.

What first sparked my interest in predictive processing was an email from a reader after my book Endure came out in 2018. I’d written about how our expectations of how a race will feel at any given point affects how hard we feel we’re able to push, based on theories from Ross Tucker and other researchers. Predictive processing, the emailer suggested, might have something to say on the topic.

I think that’s true. As you gain experience, you develop a pretty good idea of what you’ll feel like halfway through a 5K. If you feel better or worse than expected, that generates a prediction error. There are two ways of fixing prediction errors. One is to update your beliefs: I thought this pace would feel medium-hard at this point in the race, but it feels hard, so I’ll adjust my internal prediction. The other is to adjust your actions: I thought this pace would feel medium-hard, so I’ll slow down until it feels medium-hard. The second strategy is what Friston calls active inference.

Why is it that we generally adjust our pace rather than our beliefs when we’re racing? I’m not sure, but I wonder whether predictive processing will suggest some new ways of probing this longstanding question.

There’s a puzzle in predictive processing called the Dark Room problem. If the free energy principle demands that we minimize surprise, why don’t we just lock ourselves in a dark room until we starve to death? One way of answering this question is to recall that we’re not just trying to minimize present surprise; we’re also trying to minimize surprise in the future. And the best way of avoiding future surprises is to learn as much as possible about the world and how it works.

Predictive processing, in other words, wires us to seek out the unknown in order to learn about it, as a way of minimizing future surprise. This is a different way of thinking about why we like venturing into the wilderness, undertaking challenges like running a marathon, and traveling to unfamiliar places. This is an idea I’m digging deeper into for a forthcoming book on the science of exploring.

Does expressing these ideas in the language of predictive processing actually change anything? That remains to be seen. I’ve talked to some scientists over the past few years who view it as genuinely new, and others who view it more as new words for familiar ideas.

The most practical suggestion that I’ve seen comes from an Israeli scientist named Moshe Bar, who wrote a book called Mindwandering in 2022. Bar’s big idea is that we have what he calls “overarching states of mind” that reflect the degree to which we’re focusing on the “top-down” predictions generated by our brains versus the “bottom-up” observations from our senses.

When we put more weight on predictions, we become more narrowly focused on a given task; when we put more weight on sensory data, we have broader attention, are more inclined to explore, and have a more positive mood. By “zooming out”—thinking about the big picture or the future, talking to ourselves in second person—we can shift the dial toward sensory input and loosen the grip that our predictions sometimes exert on us.

Admittedly, all of this sounds a bit esoteric. But the more I read about predictive processing, and the more I talk to scientists who are developing these ideas, the more I’m convinced that there’s something interesting here. Exactly where all this will lead—well, that’s hard to predict.

Jakob Ingebrigtsen brought his remarkable 2026 season to a fitting close on home soil, winning the men’s street 1500m at the inaugural Runfest Norway in Sandnes on Friday.

Competing in front of an enthusiastic hometown crowd, the Olympic and world champion took control of the race from the early stages and maintained his authority through the finish, stopping the clock at 3:40.7.

Andreas Fjeld Halvorsen followed in second in 3:43.3, while Sigurd Tveit completed the podium in 3:47.8.

The unusual street race added another dimension to the occasion, with 273 runners taking part on the same road and sharing the course with one of Norway’s most accomplished distance runners. For the recreational participants, it offered a rare opportunity to compete alongside Ingebrigtsen in an event that brought elite athletics and mass participation together.

The victory also provided a fitting final chapter to a season that began with significant uncertainty for Ingebrigtsen. After undergoing major Achilles surgery in February, the Norwegian was forced to miss a substantial portion of the summer campaign as he worked his way back to full fitness.

His return, however, quickly developed into another championship-winning chapter. In Birmingham, Ingebrigtsen captured European 5,000m gold before adding another major title at the inaugural World Athletics Ultimate Championship in Budapest, where he won the 5,000m.

Those performances transformed what could have been a disrupted season into another year defined by championship success and a determined return to the highest level.

Now, with the Sandnes victory added to his 2026 record, Ingebrigtsen closes the year exactly where it began in spirit — overcoming adversity, rebuilding his form and once again competing at the front.

From Achilles surgery in February to major championship victories and finally a 1500m win before his hometown crowd, the Norwegian has given his 2026 season a memorable final scene.

Olympic 100m hurdles champion Masai Russell has announced her engagement to longtime partner Robert “Robbie” Springfield, adding a major personal milestone to the remarkable journey of one of America’s leading track and field stars.

Russell shared the news with her followers, revealing that Springfield had proposed and that she had accepted. Reflecting on their relationship, the Olympic champion described him as her best friend and expressed her excitement about spending the rest of her life with him.

The couple’s relationship dates back to their college years at the University of Kentucky, where both were student-athletes and competed in track and field. Russell established herself as a standout hurdler, while Springfield competed in the long jump, giving them a shared understanding of the demands, sacrifices and pressures that come with pursuing success in athletics.

Springfield has since transitioned from competition into coaching. A former collegiate long jumper, he is now part of the coaching staff at Morehead State University, where he works with the programme’s sprinters and jumpers.

Their relationship has developed alongside Russell’s rise to the top of the sport. The defining moment of her career came at the Paris 2024 Olympic Games, where she captured gold in the women’s 100m hurdles, securing her place among the sport’s Olympic champions.

Away from competition, Springfield has remained a familiar part of Russell’s journey, sharing in the demanding periods of training and competition that accompanied her pursuit of Olympic success. Their connection has consequently grown from a college athletics relationship into a long-term partnership.

The engagement now marks another significant chapter for Russell, this time away from the track. After reaching the pinnacle of her sporting career in Paris, the 100m hurdles champion is beginning a new phase of her personal life alongside a partner who has been part of her journey since their university days.

From competing on the same collegiate stage to building a future together, Russell and Springfield’s story has evolved alongside two careers shaped by track and field. The Olympic champion will now balance this new personal chapter with her continuing ambitions in athletics

The women’s race at the 2026 TCS Amsterdam Marathon is shaping up to be one of the most competitive editions in recent years, with a deep international field set to take on the fast Dutch course on Sunday, October 18.

At the centre of the contest will be four Ethiopian athletes who have already broken the 2:20 barrier, creating the prospect of a fascinating battle for victory and a possible assault on the course record of 2:16:52.

Defending champion Aynalem Desta will return to Amsterdam looking to retain her title after producing the biggest performance of her career at last year’s 50th edition. Desta won in a personal best of 2:17:37, establishing herself among the leading marathoners in the field and setting the benchmark for this year’s contenders.

Standing in her way will be fellow Ethiopian Meseret Belete Tola, a former Amsterdam champion who knows exactly what it takes to succeed on the course. Belete Tola captured the 2023 edition in 2:18:21, and her return adds another layer of experience and proven quality to an already formidable lineup.

The field also includes Mestawut Fikir Truneh, who arrives with an impressive marathon pedigree. Truneh finished runner-up at the 2024 Berlin Marathon in 2:18:48, demonstrating her ability to compete at the highest level on one of the world's major marathon stages.

Completing the quartet of sub-2:20 Ethiopians is Buze Diriba, whose personal best of 2:19:34 places her firmly among the leading contenders. With four athletes possessing credentials below 2:20, the race is likely to develop into a tightly contested battle from the opening kilometres.

The depth extends well beyond the leading quartet. Desi Jisa Mokonin, representing Bahrain, Yeshi Kalayu Chekole of Ethiopia and Nazret Weldu Gebrehiwet of Eritrea have all established themselves as serious marathon competitors with performances approaching the 2:20 mark.

Another major name to watch is Abeba Aregawi, the former 1500m world champion representing Sweden. Aregawi has successfully transferred her talents to the marathon and made headlines earlier this year by setting a Swedish national record of 2:23:12 on her debut. Her presence adds another intriguing dimension to an already high-quality field.

Amsterdam’s marathon course has consistently provided an opportunity for elite athletes to produce fast times, and this year’s women’s lineup has the depth to turn the race into a genuine test of both championship racing and outright speed.

With four athletes already inside 2:20, two former Amsterdam champions returning to the start line and several other accomplished marathoners ready to challenge them, the battle is expected to remain open deep into the race.

The ultimate target will be the Amsterdam women’s course record of 2:16:52. Whether the leading contenders can threaten that mark remains to be seen, but the quality assembled for October 18 ensures that the record will be firmly in the spotlight when the race reaches its spectacular finish inside the Olympic Stadium.

The 2026 Valencia Half Marathon is shaping up to be a thrilling contest of speed, endurance and tactical brilliance, with some of the world’s finest road runners set to converge in Spain on October 25.

Kenya’s Daniel Ebenyo and Alex Matata will be among the leading contenders, facing a formidable Ethiopian challenge spearheaded by Jemal Yimer and Tadese Worku. The field also features Rodrigue Kwizera, who boasts the fastest personal best among the leading entrants at 58:16.

Ebenyo arrives with a personal best of 59:04, placing him firmly among the athletes capable of sustaining a demanding pace over the 21.1-kilometre distance. Matata, who owns a 59:11 best, adds further Kenyan strength, while Andrea Kiptoo brings another sub-60-minute credential to the race.

Yimer has already established himself as one of the fastest athletes in the field with a 58:33 personal best, while Worku has clocked 58:35. Kenya’s Owen Korir, with a best of 58:58, further underlines the remarkable depth of the men's lineup.

Valencia Half Marathon 2026 Entries

1. Rodrigue Kwizera (Spain) — 58:16

2. Jemal Yimer (Ethiopia) — 58:33

3. Tadese Worku (Ethiopia) — 58:35

4. Owen Korir (Kenya) — 58:58

5. Daniel Ebenyo (Kenya) — 59:04

6. Alex Matata (Kenya) — 59:11

7. Andrea Kiptoo (Kenya) — 59:11

8. Thierry Ndikumwenayo (Spain) — 59:42

9. Said Mechaal (Spain) — 1:00:24

10. Adel Mechaal (Spain) — 1:02:30

Kwizera, who finished second in Valencia last year, leads the field on paper and will be seeking another standout performance on the famously fast Valencia course. With several athletes carrying sub-60-minute credentials, the race has the ingredients for an aggressive battle from the opening kilometres.

Beyond the headline names, the men’s field is deep and highly competitive, bringing together a strong collection of experienced international athletes with proven ability over the half-marathon distance. With so much quality packed into the lineup, the race promises an intriguing battle in which tactics, endurance, positioning and finishing speed could all play a crucial role in determining the eventual champion.

Yet personal bests will count for little once the gun goes off. The title could ultimately be decided by patience, positioning and the ability to respond when the pace begins to rise in the closing stages. Every surge, every tactical move and every second saved could prove decisive on the road to the finish.

With Kenya, Ethiopia and Spain represented by athletes of exceptional quality, Valencia promises a high-octane men's showdown in which the leaders are likely to be separated by only a handful of seconds. The final kilometres could provide the defining moments of a race packed with speed, ambition and anticipation.

On October 25, the question will be simple: who has the strength to command the streets of Valencia and claim the coveted half-marathon crown?

April 19, 1982. The Boston Marathon unfolded under unusually warm, sunny conditions, and by the closing stages, the race had become a private battle between two very different American runners: Alberto Salazar, already one of the biggest names in distance running, and Dick Beardsley, the Minnesota runner who had emerged as a serious marathon contender.

For roughly nine miles, from the Newton Hills toward the finish, Beardsley did much of the leading, with Salazar tucked close behind. Neither man could shake the other. They ran deep into Boston locked together, trading surges and refusing to surrender an inch as the crowds along the course grew louder.

Salazar finally made his decisive move with less than a mile remaining. He opened a small gap, but Beardsley refused to disappear. The Minnesota runner chased him through the final streets, closing again as they approached the finish.

Then came the final sprint.

Salazar held his form and reached the finish first in 2:08:52, with Beardsley only two seconds behind in 2:08:54. It was an extraordinary result: both men broke 2:09 in the same Boston Marathon, and both shattered the previous course record.

The race became known as the “Duel in the Sun,” and it remains one of the most celebrated head-to-head battles in Boston Marathon history. Beardsley had not won, but his performance established him as one of America's elite marathoners.

For Salazar, however, victory came at an enormous physical cost. Immediately after crossing the finish line, he collapsed and required emergency treatment, including several litres of intravenous saline. The combination of heat, dehydration and an all-out effort had pushed his body to the limit.

Salazar's marathon career would never again produce quite the same kind of performance. His celebrated 1981 New York City Marathon victory had produced what was initially considered a world record, although the course was later found to be short. His Boston triumph therefore became one of the defining victories of his career.

Beardsley's story would take an even more difficult turn. Injuries disrupted his career, and after returning to the highest level, he suffered a devastating farm accident in 1989. Further accidents, surgeries and severe physical pain followed, eventually leading to a long battle with painkiller addiction.

He eventually overcame that struggle and transformed the darkest chapters of his life into a story of recovery, resilience and redemption.

That is what makes the 1982 Boston Marathon more than a two-second victory.

For one extraordinary afternoon, Salazar and Beardsley produced a marathon duel in which neither man was willing to give way. One crossed the finish line first. The other finished only two seconds behind him.

Two seconds separated them at Boston. Decades later, their legendary duel remains one of the greatest chapters in marathon history.