From Norway to Flagstaff: How Double Threshold Training Is Taking Over the WorldBy Jonathan Gault
(Note this article was released early to LetsRun.com Supporters Club members. Join the LetsRun.com Supporters Club today to get all the LetsRun.com feature articles, savings on running shoes, and a super soft shirt if you join for a year).
In the fall of 2019, Northern Arizona University cross country coach Mike Smith presented his team with an idea: one month out from the first major race of the season at the Nuttycombe Invitational, they would run two workouts in one day. For the past few years, Smith had been reading about a training system popular with Norwegian athletes, and that summer had used it with his girlfriend (now wife) Rachel Schneider as she prepared to race the 5,000 meters at the World Championships in Doha. The main principle of the system was to push an athlete’s anaerobic threshold as high as possible — a threshold that marked the difference between an intensity level sustainable for long periods of time and one that could be sustained for only a few minutes before fatigue forces the athlete to slow or stop. (Some people call this the “lactate threshold” because it is the point at which lactate, a byproduct created when the body breaks down glucose for energy, begins to accumulate rapidly in the blood).
Smith already had a training system that worked. Building on the success of his predecessor Eric Heins, he had led the Lumberjacks to back-to-back national titles in his first two seasons in charge. Why change a winning formula?
Smith told his athletes to ensure they fueled and recovered properly between sessions. Then he explained the potential benefits.
“He told us this was an easier way of us getting volume in and not doing too much in one session and saving our bodies,” says Abdihamid Nur, who ran for NAU from 2019-22. “…And then he’s like, when we’re doubling at a conference meet or a national meet, it’s not going to be a big problem for you because you guys have been doing this type of training.”
The reaction among the NAU team was split. Some of the younger, lower-mileage athletes were intimidated.
“It was like, dude I’m barely hitting 70 miles a week and you’re trying to make me do 18 miles on a day that’s not a long run day?” Nur says.
The rest of the team, the veterans and higher mileage guys? Well, they were a little intimidated, too. They were also intrigued.
- Exclusive Access to VIP Supporters Club Content
- Bonus Podcasts Every Friday
- Free LetsRun.com Shirt (Annual Subscribers
- Exclusive Access to VIP Supporters Club Content
- Exclusive Discounts
- Enhanced Message Boards
“I was so excited,” says Blaise Ferro, then in his fourth year at NAU. “I was like no way, two workouts? That’s the most badass thing you can possibly do.”
“The Big, Sexy Thing” – September 19, 2019
So, on the morning of September 19, 2019, the NAU cross country squad headed to Buffalo Park in Flagstaff and ran a set of intervals. For Ferro’s group, the session was six miles of work: 1.5 miles, 1 mile, 1 mile, 1 mile, 1.5 miles, all at 5:10 mile pace, all with 70 seconds’ rest between reps (and all at 7,000 feet of elevation). That afternoon, they came back and logged another session that was four miles: 1 mile-800-1 mile-800-1 mile, the miles at 4:50 and the 800s at 2:28 and 2:26 with one minute of rest per rep. All told, it was 10 miles of volume at a decent clip — not counting warmups or cooldowns.
When it was over, Nur was totally exhausted, unsure if he’d ever be able to complete another day like that.
“I was thinking, like, this is impossible,” Nur says. “There’s no way we’re going to be able to keep doing this. All of us were laid out like, this is hard.”
Smith would not repeat the session for more than a year. But when he brought it back, in December 2020, it stuck. Now “double threshold” training, as it has come to be known, is a staple of an NAU program that has won the last three NCAA cross country titles. Almost every Tuesday, the Lumberjacks will run one set of threshold intervals in the morning and another in the afternoon. Nur, who won two NCAA individual titles last year and now trains under Smith as a professional, says double threshold is the easiest part of his training.
“I don’t even think twice about it,” Nur says. “I’m like, I know I can do this.”
If Norway is the spiritual home of double threshold, Flagstaff is its North American base. In addition to NAU, local pro groups HOKA NAZ Elite and Under Armour Dark Sky Distance use it, as do many of the international runners who come to town for training camp. So many blood-stained lactate strips litter the NAU and Sedona tracks these days — the telltale sign of a threshold session — that it has drawn complaints.
“It’s kind of all the rage these days, double threshold,” says American miler Hobbs Kessler, who began using double threshold while training in Flagstaff last fall and ran 3:32 for 1500 meters last month. “It’s like the big, sexy thing.”
It is hard to argue with the results. Jakob Ingebrigtsen has won world and Olympic titles and last Friday set a world record of 7:54.10 for two miles thanks to a steady diet of double threshold sessions. Norwegian triathletes Kristian Blummenfelt and Gustav Iden, the reigning Olympic and Ironman triathlon champions, both use it. Double threshold has taken Luis Grijalva to 4th at Worlds in the 5,000 meters and a 12:52 personal best. Woody Kincaid used it in building up for his North American indoor record in the 5,000 meters in January. Ditto Cam Levins ahead of his 2:05:36 North American marathon record in Tokyo in March.
More than a century of data has taught us there is no perfect, one-size-fits-all training system. But double threshold is most definitely having a moment. How did we get here? It all starts with a Norwegian exchange student…
The Norwegian Connection
By most standards, Marius Bakken‘s freshman year at Indiana University had gone pretty well. In the fall of 1997, Bakken finished 28th at the NCAA Cross Country Championships. On the track, he ran 3:48 for 1500, 8:13 for 3000, and 30:16 for 10,000 meters — solid freshman times in the pre-supershoe era. But for Bakken, solid was not going to cut it.
Though Bakken was only 20 years old, by the spring of 1998 he had already received a master’s-level education in the sport of running. Growing up in Sandefjord, 90 minutes south of Oslo, Bakken had been coached by one of Norway’s greatest runners, Per Halle, who finished 7th at the 1972 Olympics in the 5,000 meters. As a senior in high school, Bakken enrolled in a US exchange program and, because of his interest in running, wound up at York High School, the distance powerhouse coached by the legendary Joe Newton in Elmhurst, Ill., where he won state titles in the 1600 and 3200 meters (Bakken was 4th at the state cross country meet; York finished 2nd, breaking a six-year win streak). After York, Bakken went to London, where he was coached for a year by Peter Coe, who guided his son Sebastian to world records in the 800, 1500, and mile.
At Indiana, Bakken trained under Sam Bell, who had coached America’s top distance runner at the time, Bob Kennedy. Bell’s training had worked for Kennedy, who set an American record of 12:58 for 5,000 meters in 1996. Bakken wanted to be world-class too, but quickly realized he was not as talented as Kennedy. He could not simply replicate Kennedy’s training and hope for the same results.
“The training, it was too low in volume,” Bakken says. “It was more of a traditional system where you do two hard workouts a week and you do a fair number of miles but not even close to what you can do with double threshold. So what I could see is that this wouldn’t bring me to that next level.”
So Bakken returned to Norway in 1998 and began pondering how to close the gap to Kennedy. Bakken knew that, compared to other endurance athletes such as cyclists and cross country skiers, runners did a smaller percentage of their training at high intensity (80-85% of max heartrate).
“We know that the cardiovascular system, it’s no problem doing that type of work for much, much longer than what is usual for runners,” Bakken says. “The limiting factor for runners is the muscular system because you have the footstride, you land, you have the bodyweight in each landing.”
The question, then, was how to train more than Kennedy without his body breaking down from the extra stress. Threshold training was the answer. Using a meter to measure his lactate levels during workouts, Bakken found that if he could keep his blood lactate concentration between 2.3 and 3.0 mmol/L, he could get the most bang for his buck, driving his anaerobic threshold higher without wearing down his body too much ahead of the next session.
A few years earlier, Coe had occasionally assigned Bakken “top-up mileage” weeks to preserve his endurance, which consisted of two threshold sessions a day multiple times a week. Bakken also trained with Leif Olav Alnes, who would go on to great acclaim as the coach of Olympic 400m hurdles champion Karsten Warholm, and noticed how Alnes’ sprinters would cluster multiple hard workouts into a single day. Working with another Norwegian coach and proponent of threshold training, Frank Evertsen, Bakken began experimenting with the frequency of sessions.
Two per day. Three per day. Four per day. Back-to-back workouts days. Bakken tried it all.
The “X” Element
After a lot of sweat and a lot of blood — more than 5,500 lactate tests — Bakken found the system that worked best for him: two days a week of “double threshold” (threshold sessions in the morning and afternoon) paired with one higher intensity workout he called the “X element.”
Because coaches are constantly borrowing from one another, it is hard to call anything in distance training truly unique. Two workouts in a day? It had been done before, notably by Italian coach Renato Canova as part of his “special blocks.” At times in the 1980s, Sebastian Coe would do two, or even three sessions in a day. That included double threshold.
“Interspersed throughout the season, not at set times,” Coe writes in an email to LetsRun.com. “And yes, I did enjoy them because I always wanted to run quickly rather than slowly. Peter Coe infamously said ‘Long slow running turns you into a long slow runner.'”
But as far as Bakken knew, he was the first runner to build a program around double threshold training.
It did not take long for Bakken to see results. Within a year of shifting to a threshold-based approach, he had dropped his personal best from 8:13 to 7:47. Bakken would make two Olympic teams, two World Championship finals (with a best finish of 9th in 2001), and run a personal best of 13:06.39 for 5,000 meters in 2004. That time made him the third-fastest European-born man in the 2000s and would last as the Norwegian record until 2019, when it was broken by Jakob Ingebrigtsen.
Bakken had a hand in that as well, of course. Toward the end of his career, Bakken had trained alongside a steepler, Bjørnar Kristensen. At the time, Kristensen was coached by Eric Toogood, who later coached a promising 1500-meter runner by the name of Henrik Ingebrigtsen, to whom he introduced the double threshold sessions he had picked up from Kristensen.
When Henrik’s father, Gjert, took over as his coach in 2012, he kept many of the same elements in place. In a 2021 interview with the Norwegian podcast In the Long Run and in his book, Gjert downplayed the influence of Bakken in the training system he used with his sons. Bakken, on the other hand, says their correspondence included multiple emails, texts, and phone calls with specific training questions. Bakken published some of those emails last year.
After the 2021 season, Gjert stopped coaching Henrik and his younger brothers, Jakob and 2017 Worlds 1500 bronze medalist Filip. But Bakken says the Ingebrigtsens still utilize the double threshold principles he developed more than two decades ago, alongside their own specific adaptations during the competition season.
“The base training I know is very similar,” Bakken says. “They do the 1500 mostly, so the summer training is more oriented towards the 1500.”
(LetsRun requested interviews with Henrik Ingebrigtsen and Jakob Ingebrigtsen, via his agent Daniel Wessfeldt, for this story. Neither Henrik nor Wessfeldt responded).
Bakken has come to be known as the father of double threshold training and as a result receives emails from coaches and athletes all over the world asking for his help. Bakken has been out of the sport for more than 15 years now — he works full-time as a general practitioner in southern Norway — and answering those questions took up much of his free time. So in January 2022, he composed a lengthy blog post outlining the system, partially to share the lessons he had learned through years of experimentation and partially to share the credit with the coaches who helped refine the system. That post — “The Norwegian model of lactate threshold training and lactate controlled approach to training,” — has become the Bible of double threshold training.
“It was important for me to give a historical perspective that this was developed over time with lots of different people involved,” Bakken says.
Coe, now World Athletics president, also believes it is important to honor the past.
“I have spoken to the Ingebrigtsens’ coach who acknowledges my father’s coaching philosophy,” Coe says. “My father called it 5-tier training. Each tier had a very specific physiological stimulation. I am a big believer of understanding the history of the sport. El Guerrouj followed the same system. Every generation is influenced by groundbreaking thinking of the previous generation…Become students of your sport. Good coaches do that.”
Jakob Ingebrigtsen, 22, is most definitely a student of the sport, often stressing the importance of understanding one’s own training. His history, however, still needs a little work. After winning the Bowerman Mile at last year’s Pre Classic, Olympic organizers approached Ingebrigtsen in the mixed zone and handed him a pen and a piece of paper, asking him to write his goal for Paris 2024.
Ingebrigtsen took the black Sharpie and wrote, Been there done that. Let’s be the first to do back-to-back.
LetsRun’s Robert Johnson offered a gentle correction: someone else had already done it. And if Ingebrigtsen wins his second Olympic 1500 gold medal next summer, you can trace a double thresold through line to the first back-to-back champ, 40 years earlier: Sebastian Coe.
Hobbs Kessler Joins the Bandwagon
While double threshold training has been popular in Norway for a number of years, the success of the Ingebrigtsen brothers, especially Jakob, caused it to spread worldwide. Smith, who learned about the system by reading Bakken’s old blog posts from the early 2000s, was one of the first to bring it to North America, taking advantage of the flexible schedule afforded by virtual classes during the COVID pandemic to introduce it at NAU during the 2020-21 school year. Now, more and more coaches are incorporating its principles.
Hobbs Kessler first read Bakken’s blog last summer. He was intrigued by double threshold training, and though the system’s growing popularity had made him hesitant — “it’s almost too popular, too cool,” Kessler says — he ultimately decided it made too much sense to ignore.
For Kessler and the rest of coach Ron Warhurst‘s Michigan-based Very Nice Track Club, Mondays serve as their easy days, after which they typically meet at Kessler’s parents house in Ann Arbor for coffee, brunch, and an informal skull session. Kessler is a questioner by nature, and when he broached the topic of double threshold one Monday last fall, it was not the first time he had pitched a new training idea to Warhust. Kessler’s older teammate, 2021 steeplechase Olympian Mason Ferlic, loves that about him — Ferlic is a questioner, too — but says it has become something of a running joke about what idea Kessler will pitch next.
“We’re like, dude you, literally a month ago, had a different opinion,” Ferlic says.
The 79-year-old Warhurst welcomes input from his athletes, so when Kessler initially suggested double threshold, Warhurst was not against the idea. He just required a little convincing.
“Not from the fact that he didn’t think it worked, he just does believe that what we’ve done has also worked,” says Ferlic. “If you just chase the new hottest thing, one year you’re going to be running long slow distance, the other year you’re going to be ripping 200’s/all-out speed in December. The running training, Ron’s seen it all.”
After talking it over, Warhurst gave Kessler the green light to use it while training in Flagstaff last fall. And while Warhurst has not overhauled his entire coaching system, he has begun using it with Ferlic and Ben Flanagan, too.
“I don’t think it’s a magic bullet, to be honest, but I see some theory behind it,” Ferlic says.
The “Norwegian Model”
The system Bakken developed in the 1990s and 2000s — what has now come to be known as the “Norwegian model” — had a few basic principles.
- Two double threshold days per week (usually Tuesdays and Thursdays).
- Workouts are “broken” into intervals with short rest instead of a continuous tempo run in order to maximize volume at a faster pace without exceeding threshold. A typical day might consist of 5 x 2k with one minute rest in the morning and 10 x 1k with one minute rest in the afternoon. (See a sample week here, taken from Swedish athlete Kalle Berglund).
- The amount of rest between sessions is not overly important as long as the athlete is sufficiently recovered.
- The second session of the day features shorter reps run closer to threshold pace.
For Bakken, double threshold training was most important during his base phase. Once the serious competition season began in the summer, he would focus more on race-specific work, limiting his threshold work unless he was at altitude camp.
“The goal until, let’s say, May 1 is to push your anaerobic threshold as high as possible,” Bakken says. “From May 1, your goal is to see how little threshold training you need to do to keep it at the level it needs to stay when doing race work.”
The specific implementation of double threshold varies between training groups. With NAU, Mike Smith uses double threshold pretty much year-round, typically once a week. Cam Levins, who began using double threshold under his coach Jim Finlayson starting in 2021, incorporates a double threshold day once every two weeks early in his marathon buildups but typically stops doing them in the last six weeks before a race as he shifts toward longer, marathon-specific sessions.
Stephen Haas, coach of Under Armour’s Dark Sky Distance team, started using double threshold with his athletes last year and operates on a sliding scale. A high-mileage athlete like Jacob Thomson, who won the US Half Marathon title in February, may use it once a week. Eduardo Herrera, a 1500/5000 runner, might do it every other week. And Weini Kelati doesn’t do it at all. Yet.
“I think she would do really well but I’m scared to implement it with her as she’s lower volume,” Haas says. “A big volume day for her right now is eight miles. It’s not something I’m going to try with her right now until we get her volume up a little bit more.”
Measuring Sticks & Holding Back
To ensure he was staying in the right training zones, Bakken would obsessively track his lactate levels by constantly pricking himself in workouts, measuring the results with a lactate meter. Many groups still do this, but not all. Levins goes by feel — marathon effort for morning sessions, half-marathon or 10k effort in the afternoon. NAU doesn’t measure lactate either — Smith goes off respiration.
Double threshold training offers a few more benefits beyond improving an athlete’s anaerobic threshold. Ferro says the workouts are great at replicating the “dull ache” of a 10,000-meter race. Finlayson believes those benefits extend to longer races as well.
“We’ve gone up to about 12k in the morning and 10k at night, so we’re 22k of volume in a day,” Finlayson says.”There aren’t many workouts where you would get that much volume. Whatever the benefit is physiologically, I won’t speak to that. But just to get 22 kilometers of volume on your feet at that pace does seem to have a really positive benefit for later in races, whether it’s the last 5k of a half marathon or the last 7k of a marathon.”
Ferlic believes the biggest reason athletes are experiencing success with double threshold is that it forces them to carefully measure their effort during sessions, helping them train in the proper zones rather than overdoing it. Such an approach can help reduce injury and burnout — two byproducts of digging too deep in practice.
“Instead of people going to the well in what should be a tempo session, they’re limited by the psychological notion that they have a second workout six hours from now,” Ferlic says.
Haas says his role as coach is often to hold athletes back from doing too much, especially at 7,000 feet of elevation.
“I’ve seen so many athletes come up here [to Flagstaff] and overtrain,” Haas says. “The whole idea here within this threshold is staying below your redline and I think it’s a real smart way to train up here.”
Of course, it’s easy to overdo it with double threshold training as well. Run too fast in sessions or fail to recover properly in between and double threshold quickly becomes unsustainable.
“I’d say food and sleep are probably your biggest [risk] factors,” Ferro says. “…If you’re a little underweight or not fueling properly, two sessions in a day is going to kill you and you’re going to end up injured and tired.”
The Super Shoe Impact
In 2023, there is one tool that was not available to Bakken when he developed the system in the ’90s: foam-packed super shoes, which reduce pounding and speed up recovery between sessions. Both Ferlic and Levins believe the shoes have made double threshold training feasible for a larger group of athletes who would have broken down had they attempted it in traditional flats.
“Based on how I feel coming out of a workout with the supershoes, I think it would take a very special athlete to be able to do it without them,” Levins says.
Yet we know from Bakken’s own results that it is possible to have success with double threshold without the shoes.
“Even though the wear is less when you’re doing it in the supershoes, you still have the same type of challenges in terms of back-to-back-sessions in terms of recovery,” Bakken says. “So I think it doesn’t matter as much as you would think.”
So if it’s possible to recover well enough to run two threshold sessions in one day, why doesn’t anyone run double threshold every day?
“It’s not a stupid question,” says HOKA NAZ Elite Executive Director Ben Rosario, whose team started using double threshold in 2022. “Because it’s like, why wouldn’t that be possible, right?”
Bakken says it has to do with muscle tone — a topic on which he wrote his master’s thesis — which refers to the stiffness of muscles at rest between sessions. Bakken found that a few hours’ recovery was enough to reduce muscle stiffness after a threshold session — but only if the body was recovering for longer once the day was done.
“If you do it every day, what happens is your muscle tone will not go down in the day between,” Bakken says. “So you will have a continuous buildup and then you go into overtraining.”
Most coaches interviewed for this story could not give a definitive scientific answer for why it is not possible to run double threshold sessions every day. But all of them say the history of distance running has shown that recovery must be built into any effective training system. Rosario’s theory is similar to Bakken’s, suggesting that it is related to delayed-onset muscle soreness (DOMS), which sets in the day after the workout rather than the day of. But he admitted that is only a theory.
“I know things are ‘more scientific’ these days, but at the same time, it’s no different from what Paavo Nurmi was doing or Emil Zatopek trying to run in boots,” Rosario says. “You try things, you see what works. And you stick with what works and you shove what doesn’t work in the garbage can.”
The Latest Fad or the Future of Training?
Will double threshold training end up in the garbage can one day? Is this just the latest distance running fad?
A decade ago, when Galen Rupp started running workouts after smashing American records left and right, it felt as if the Oregon Project had unlocked another level of training. Now? Plenty of great athletes still run post-race workouts. Plenty more don’t. Both groups have found success.
Bakken says he believes double threshold training is most effective for 5k/10k athletes. Obviously, it can work for milers as well — the reigning Olympic 1500 champion is one of double threshold’s biggest proponents — but only a certain type of miler. If you’re an 800/1500 type, double threshold may not be for you.
NAZ Elite’s Cruz Culpepper saw Ingebrigtsen’s success and loaded up on threshold workouts last year. But he abandoned the idea after a frustrating fall of workouts, concluding that his strengths as a runner were not the same as Ingebrigtsen’s.
“[Ingebrigtsen] is taking advantage of all he has to work with,” Culpepper says. “And that’s the name of the game – what do you have to work with and are you capitalizing on it?”
Beyond Smith at NAU, other NCAA coaches have begun experimenting with double threshold. Under coach John Hayes, the Wake Forest men, who finished 5th at the NCAA Cross Country Championships in November, use it now too, often twice a week. It’s a riskier tactic to employ at the collegiate level, in part due to logistics, in part because of the nature of a college team. As a younger runner, there is pressure to run fast in workouts, whether it’s to show others that you belong or to show yourself that you are making progress. But just because you can run faster does not mean you should.
“This season, there are a lot of guys who are getting kind of burned out just because we were running our threshold pace just that touch too quick,” Wake’s Zach Facioni (13:27 5k, #5 in the NCAA this year) told the Runner’s Tribe Podcast. “So we all slowed it back 4-5 seconds a mile and everyone started running better afterwards. So it’s a really fine line.”
Recently, NC State coach Laurie Henes started using double threshold with one of her post-collegiate athletes Hannah Steelman, who now trains in Flagstaff with Henes’ daughter Elly (coached by Smith). But Henes does not use it with her college team — which has won the last two NCAA women’s cross country titles. She says there are a number of barriers to implementing double threshold with collegians.
The Time Commitment
For Henes, the biggest issue is time. When professionals have a double threshold day, they can spend the hours between sessions napping or lying on the couch watching Netflix. Henes does not think it is feasible to schedule two workouts a day around class and homework and still expect collegiate athletes to stay on top of their recovery.
“Some of [our athletes] are in pretty hard majors,” Henes says. “…While we would love to get everyone to bed at 10:30 or 11, it’s not always doable with the academic piece of it…I definitely see the benefit of [double threshold] but for us, the inability to completely rest between sessions, I just don’t think we could recover the way we want to.”
Henes also says she is careful not to ask too much of athletes while they are still in their teens and early 20s. Double threshold is a potential tool for improvement, but if it’s something her athletes don’t start until after college, she is fine with that.
“I want to be leaving room for athletes to have things to do after college instead of milking all of that out of them,” Henes says.
At the professional level, Rosario and Haas say they still expect to be using double threshold workouts five years from now, largely because threshold training had already been a major part of their programs. Finlayson also says he plans to continue using it with his athletes, but doesn’t expect double threshold to completely take over the sport.
“I don’t know that everybody will necessarily be able to absorb it and adapt to it, but I think you’ll see more and more people seeing how it goes for them,” Finlayson. “I don’t think it’s going to go away. I don’t want it to go away. I like it.”
Plenty of other athletes and coaches like it, too, but there has always been more than one road to the top in distance running. Neither the Bowerman Track Club nor the On Athletics Club — the United States’ two most successful professional distance teams — use double threshold. And while the system propelled Ingebrigtsen to a World Championship gold medal at 5,000 meters last summer, he finished second in the 1500 meters to Jake Wightman, an athlete who has never run a double threshold day in his life. That doesn’t mean Wightman’s training system is “better” than Ingebrigtsen’s. It’s just different.
“Good athletes are going to run well when they believe in the system in which they’re training and they’re healthy and ready to go on race day,” Rosario says. “There’s no magic bullet. There never was and there never will be. You can see that with Ingebrigtsen vs. Wightman. They train very differently and yet they’re the two best in the world.”
Talk about this article on our world-famous fan forum / messageboard. MB: The secrets of double threshold training are revealed. From Norway to Flagstaff: How Double Threshold Training Is Taking Over the World.
(Note this article was released early to LetsRun.com Supporters Club members. Join the LetsRun.com Supporters Club today to get all the LetsRun.com feature articles, savings on running shoes, and a super soft shirt if you join for a year).
More Reading: The Norwegian model of lactate threshold training and lactate controlled approach to training
LRC Discussion: Must read: Marius Bakken (13.06 5k) very thoroughly on how the Ingebrigtsens have copied his training