If I had an Etsy shop, the catchphrase on all my merch would be “Everything I know about endurance training I learned from the 1964 Olympic 5,000-meter final.” As Mayo Clinic physiologist Michael Joyner pointed out a few years ago, it was a clash of vastly different training approaches:
-Bob Schul trained under Hungarian coach Mihály Iglói, running almost nothing but short intervals on the track, usually twice a day.
-Harald Norpoth was the most famous disciple of German coach Ernst Van Aaken, who advocated a diet of almost exclusively “long slow distance,” or LSD.
-Bill Dellinger was guided by University of Oregon coach Bill Bowerman, whose guiding principle was alternating hard days with easy days, a mixed approach that remains overwhelmingly popular today.
-Ron Clarke did what we would think of as threshold training—long, moderately hard runs of between three and 14 miles—up to three times a day, every day. “Any variation,” according to Fred Wilt’s book How They Train, “[was] unintentional.”
So which approach worked best? Schul, Norpoth, and Dellinger took the medals, separated by a mere second. Clarke was farther back, but went on to break the world record the next year. Give them springy shoes, an all-weather track surface, pacing lights, and maybe a little prize money, and all of them (Clarke in particular) would still be world-class today.
All of this is to say that I’m not a big believer in magic workouts or secret training plans. Endurance training involves stressing your cardiovascular system, metabolism, and muscles in a way that spurs them to adapt. There are many different ways of organizing your training in order to accumulate as much of this stress as possible, while allowing enough recovery between sessions. The wheel gets reinvented on a regular basis, but it’s still a wheel.
Still, I can’t help being impressed with the rapid spread of what’s becoming known as the “Norwegian model” of endurance training. Its most famous current proponents are the Ingebrigtsen brothers, including Olympic 1,500 champion Jakob, as well as Olympic triathlon champion Kristian Blummenfelt and Ironman world champion Gustav Iden. There’s nothing new about success begetting imitation, but what has caught my attention is the anecdotal reports I’ve heard from other athletes who’ve tried switching to the Norwegian model and are convinced it really works. It’s enough, at least, to make me curious about what it’s all about.
To that end, a new review paper in the International Journal of Environmental Research and Public Health (freely available to read) takes a stab at laying out the science of the Norwegian model. The lead author is Arturo Casado, a former Olympic miler from Spain. Co-authors are scientists Carl Foster and Leif Inge Tjelta, both influential training theorists, and Marius Bakken, a former Norwegian 5,000-meter star who is credited with developing and popularizing the approach. (That claim is not without controversy: Gjert Ingebrigtsen, Jakob’s father and former coach, has minimized the importance of Bakken’s influence. Last year Bakken published a detailed manifesto on his website laying out the history of the training model and reproducing email and text exchanges with Gjert to demonstrate the transfer of knowledge.)
Instead of “Norwegian model,” the title of the paper refers to “lactate-guided threshold interval training within a high-volume low-intensity approach.” The second element, the high-volume low-intensity bit, is not particularly novel. It basically means doing a lot of easy running and just a small amount of intense training, along the lines of what’s sometimes referred to as polarized training. There’s an ongoing debate about the nomenclature, and about whether elite athletes do polarized training or a related concept called pyramidal training. But the basic idea—a lot of easy miles and few hard ones to maximize the overall stimulus of various types of adaptation—is widely accepted.
The new bit is the lactate-guided threshold interval training. A typical training week, according to the paper, involves a total of about 110 miles of mostly easy running. Tuesdays and Thursdays both include threshold intervals in the mornings and evenings, and Saturdays see a more intense workout, such as 20 x 200-meter hill sprints.
The key point about the threshold intervals is that they’re not run to any external benchmark like pace. What matters is only the internal stress on the body, so lactate levels are measured repeatedly throughout the workout with a finger or ear prick to ensure that they stay in the desired range. In this case, the desired range is “threshold”—or, more precisely, between the first and second lactate thresholds, which generally corresponds to lactate levels between 2.0 and 4.5 mmol/L. Bakken himself found the best results when keeping his lactate below 3.0 mmol/L.
Why this range? As soon as you push above the second lactate threshold—or, semi-equivalently, above your critical speed—the time required to recover from exercise increases dramatically. One study found that fatigue was four to five times greater for exercise 10 percent above the critical threshold than for 10 percent below it. So by carefully keeping below that threshold, you can accumulate a far greater amount of training time at an intensity that’s still challenging enough to spur useful adaptations. In fact, you can recover quickly enough to do one session in the morning and another in the evening… and then do the same thing two days later.
Another key characteristic is that the threshold sessions are broken into intervals. If you simply do a continuous threshold run, you’ll have to keep your speed relatively low to avoid lactate levels drifting upward. By adding rest periods, you can run a little faster, thus triggering more race-specific muscle adaptations, without accumulating too much metabolic fatigue. These workouts are often done on the treadmill, making it easier to keep the pace under control, minimize accidental surges due to variations in terrain, and do the lactate testing.
In the sample training week provided in the paper, the four threshold interval workouts are:
-Tuesday morning: 5 x 6:00 at 2.5 mmol/L with 1:00 recovery
-Tuesday evening: 10 x 1,000 meters at 3.5 mmol/L with 1:00 recovery
-Thursday morning: 5 x 2,000 meters at 2.5 mmol/L with 1:00 recovery
-Thursday evening: 25 x 400 meters at 3.5 mmol/L with 0:30 recovery
For that last workout, the authors report observing “international level distance runners” running the 400-meters reps in 64 seconds while keeping lactate below 4.0 mmol/L. That’s just over 4:16 mile pace, which is quite a bit faster than what we usually think of as “threshold,” even for top runners. But the interval structure keeps it from becoming a sufferfest that will take too long to recover from. The anecdotal reporting I’ve heard is that runners who are used to hammering interval workouts really struggle to go easy enough in these sessions, especially at first. But over the course of a few months, the pace they’re able to sustain without spiking their lactate levels quickens dramatically.
There are lots more nuances to implementing the Norwegian model—like how to adjust your training as a big race approaches—which you can dig into in both Casado’s paper and Bakken’s manifesto. But those double-threshold days, broken into intervals with tightly controlled lactate levels, are the distinguishing element. Casado and his colleagues close with a call for proper studies to see if this approach really does outperform the alternatives. Those are really hard studies to do, and I don’t expect that we’ll get definitive answers anytime soon. So the next test, as far as I’m concerned, will be the 2024 Olympics—and we’ll see if the battle of training strategies produces a more definitive outcome than that 1964 race did.
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