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If you’ve spent any time on running social media or talked with teammates, you’ve probably heard the term double threshold. If you’re reading this, you’ve likely also heard of the “Norwegian method,” which has gained significant attention in recent years thanks to athletes such as Olympic champion Jakob Ingebrigtsen and triathlete Kristian Blummenfelt.

The Norwegians have been measuring and testing their blood lactate since the late 1990s. Their workouts are tightly controlled, often guided by lactate testing, and built on years of consistent high mileage. However, to fully understand this method, we need to go back to Marius Bakken, a former Norwegian runner and physician, often called the “godfather of double threshold”, who specialized in the 5,000 meters and helped popularize this approach.

Bakken attended high school in Illinois, where he was coached by the legendary Joe Newton, and later by Peter Coe. While working with Coe, his performance stagnated between 1996 and 1998. However, Coe also implemented “top-off” weeks of high mileage, which Bakken later said he responded to more effectively.

With all this success at the highest level, it’s natural to ask: If the best runners and triathletes in the world are doing this, shouldn’t I be doing it too?

Not so fast.

Before answering that question, it’s important to understand what double threshold training actually is, and what it is not.

What Is Threshold Training?

Threshold training refers to an intensity where blood lactate remains relatively stable after the initial aerobic rise (LT1), with the upper boundary being LT2.

At the lower end (just above LT1), a well-trained runner can sustain the effort for around two hours. At the upper end (LT2), the effort may only be sustainable for approximately 20–40 minutes. Elites can hold LT2 much longer.  

What Is Double Threshold Training?

A double threshold day typically consists of two interval sessions, one in the morning and one in the evening. Some elite athletes monitor their lactate levels in real time.

The morning session often includes longer intervals, such as 5 × 2K with 1-minute jog recovery, while keeping blood lactate levels about 0.5–1.0 mmol below threshold. An example evening session might be 20–25 × 400 meters with 30 seconds of rest, with lactate levels at or slightly above threshold.

The key principle is control. These athletes are not pushing to the point of exhaustion. Instead, they use short rest periods to keep heart rate elevated and maximize time spent at threshold.

The key principle is control. These athletes are not pushing to the point of exhaustion. Instead, they use short rest periods to keep heart rate elevated and maximize time spent at threshold.

They also emphasize accumulating more volume at threshold rather than running faster. When intensity is controlled correctly, more volume can be completed without excessive fatigue. Many of these athletes use lactate meters to guide effort in real time. For those without access to lactate testing, heart rate is the next best way to regulate intensity.

For elite runners, this effort typically falls somewhere between half marathon and marathon pace. They are not redlining or approaching VO₂ max. However, double threshold training can still improve VO₂ max, as adaptations can occur within the 80–100% intensity range.

The Importance of Controlling Intensity

Many runners rely solely on threshold pace, but physiological responses, such as blood lactate can vary from day to day based on sleep, stress, environment, and fitness.

If you’re using pace-based sessions, adjustments should be made based on heart rate, fatigue, heat, and humidity. Running these sessions too fast – overshooting your threshold – creates excessive metabolic stress, reduces your ability to accumulate volume, and leads to fatigue that negatively impacts subsequent training.

Without an accurate understanding of your threshold or physiological profile, threshold training can lead to performance plateaus and chronic glycogen depletion, often associated with overtraining or underfueling.

Training at threshold too frequently or pushing too aggressively can also overstress the sympathetic nervous system and delay recovery. Like all physiological training, careful attention must be given to workload whether it’s threshold, high-volume Zone 2, or VO₂ max work.

Overemphasizing any single system can be counterproductive. Balanced training ranging from easy aerobic work to VO₂ max and neuromuscular efforts is most effective when applied appropriately based on the athlete’s stage of development.

Threshold Training for High School Runners

For high school runners, who often race under 20 minutes, it makes little sense to focus exclusively on threshold training.

Instead, they should develop all energy systems. That said, threshold training still has value. In fact, the summer months can be an excellent time to emphasize it. When used appropriately, it can help support improved performance at 5K pace and faster.

Clearing Up Misconceptions About Lactate

A common misconception is that lactate causes soreness, acidosis, and fatigue.

In reality, lactate is a valuable fuel source and is produced even during aerobic efforts. It is continuously utilized in the presence of oxygen, playing an important role in energy production.

Why Double Threshold Has Become Popular

With the success of athletes like Kristian Blummenfelt and Jakob Ingebrigtsen, double threshold training has gained widespread attention.

As a result, many high school runners are beginning to ask whether this method is appropriate for them.

Should High School Runners Do Double Threshold?

In most cases, no.

There are several foundational elements that should come first. High school runners typically lack the years of aerobic development that elite athletes possess, and there is still significant room for gradual mileage progression.

Additionally, many high school athletes have limited experience with even easy double runs. When appropriate, 1–2 easy doubles per week can be introduced, but not at threshold intensity.

It’s also important to consider a teenager’s adaptability. While younger athletes may recover quickly, that does not necessarily mean they adapt effectively. Often, doing slightly less than what feels possible leads to better long-term progress.

It’s also important to consider a teenager’s adaptability. While younger athletes may recover quickly, that does not necessarily mean they adapt effectively. Often, doing slightly less than what feels possible leads to better long-term progress.

It’s worth noting that Norwegian athletes have typically spent a decade or more building an aerobic base before incorporating double threshold training. For example, Jakob Ingebrigtsen began running at 8–9 years old and became the youngest athlete to run a sub-4-minute mile at age 16. He may have been running up to 60 miles per week by age 12.

Better Alternatives to Double Threshold

Rather than jumping to advanced methods, high school athletes should continue building gradually.

Alternatives such as “flux training”—alternating intensities like 400m at threshold followed by 200m float—can be highly effective. This approach helps train the body to utilize lactate as fuel and improve its clearance.

Another option is “critical velocity” intervals, typically consisting of 800m to 1600m repetitions totaling 20–25 minutes at approximately 30–35 minute race pace.

From there, athletes can progress by adding a threshold run alongside an easy aerobic double, gradually increasing frequency before increasing duration.

The Risks of Copying Elite Training

Copying elite training too soon can be risky.

Pushing advanced training before you’re ready can lead to burnout, injury, and stagnation. Instead, athletes should focus on building layer upon layer and gradually incorporating easy doubles and increasing mileage toward 40, 60–80+ miles per week over time.

Elite runners often have more than 8 years of consistent high-volume training, sometimes exceeding 100 miles per week. They also prioritize sleep and nutrition at a high level more so than student athletes who are managing school stress and they may be involved in other organizations that require more of their time. 

High school athletes, by contrast, are still developing physically, hormonally, and neurologically. You may feel fine doing large amounts of threshold work until suddenly you don’t. Recovery demands can be significantly higher due to limited training history and ongoing development, and external factors such as school. 

When Might Double Threshold Be Appropriate?

Double threshold training may only be appropriate after carefully evaluating sleep, injury history, consistency, and external stressors.

Developmentally, this might not be suitable until ages 17–18, and only for athletes with a substantial aerobic base and high durability. Even then, the second session should be shorter and tightly controlled.

It’s also important to review training history to determine whether simpler, more effective improvements can still be made.

Final Thoughts

Before adding double threshold training, an athlete should be highly consistent, healthy, and durable.

Coaches must also consider injury history, sleep quality, nutrition, and external stressors such as school, jobs, and relationships. The body does not distinguish between training stress and life stress. They both activate the same physiological “fight-or-flight” response, increasing cortisol and impacting recovery.

In the end, the goal isn’t to copy what elite athletes are doing, it’s to build the foundation that allows you to eventually train like them.

Sources:

Bakken, Marius. “-.” Marius Bakken, https://www.mariusbakken.com/the-norwegian-model.html. Accessed 24 March 2026.

Culp, Brad. Norwegian Method: The Culture, Science, and Humans Behind the Groundbreaking Approach to Elite Endurance Performance. 80/20 Publishing, 2024.

Grady, Shannon. The Lactate Revolution: The Science of Quantifying, Predicting, and Improving Human Performance. BookBaby, 2020.

William Ritter, from Tyler Texas, enjoys working with athletes that are looking to improve their performance in triathlon or running. He specializes in coaching triathletes and runners of all abilities. Ritter’s coaching is extensive and focused on the individual athlete, blending the art and science of coaching. Ritter is the Head Coach at Fly Tri Racing with over 15 years of coaching experience and 30 years of competitive experience. Coach Ritter is a USA Triathlon Level II Short & Long Course Coach, USA Triathlon Level 1 Youth & Junior Coach, USA Track & Field Level III Endurance & Youth Coach and USATF Cross Country & Marathon Specialist. Including a TrainingPeaks Level 2 and Power Certified Coach, Ironman U, Tri Sutto Coaching Certified, USA Cycling Coach.