A Deep Dive into the Norwegian Training Model and Its Impact
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The Norwegian training model, often associated with the Ingebrigtsen family's training methods, has gained significant media attention lately. Coaches and athletes are increasingly discussing "double threshold sessions," with many claiming these to be the secret to their success. Additionally, the long-standing practice of monitoring blood lactate levels during training has become popular among both recreational and elite runners. But what exactly does The Norwegian Model entail, and how does it function in practice?
In this article, I will explore two distinct models of training intensity distribution (TID): polarized and threshold training. I will clarify the concepts, terminology, and physiology driving the interest in The Norwegian Model and contrast it with polarized training. I will also evaluate the differences between the two approaches and discuss why the "Ingebrigtsen style" might be effective for elite athletes but may not yield the same results for beginners and casual runners. Ultimately, I will offer my insights from both theoretical and practical perspectives.
Intensity Zones 1–5
Categorizing training intensity into distinct "zones" can be complex and contentious. This ranges from the relaxed state of lounging on the couch to the extreme exertion felt during the final moments of a race or interval workout. However, guidelines can be beneficial. Physiologically, there are three main intensity zones, defined through blood lactate (or ventilation) measurements. The first transition point usually occurs around 2 mmol, while a sharper increase is noted at approximately 4 mmol, corresponding to heart rate percentages of about 80% and 87% of HRmax (the highest heart rate achieved during training). These transition points are commonly known as the "aerobic threshold" (LT1/VT1) and "anaerobic threshold" (LT2/VT2). While I present reference values, significant individual variations exist among athletes, which is why testing is essential.
The Norwegian Olympic Federation has further divided these three zones into five distinct training zones:
- Zone 1: 55–72% of HRmax
- Zone 2: 72–80% of HRmax
- Zone 3: 80–87% of HRmax
- Zone 4: 87–92% of HRmax
- Zone 5: 92–100% of HRmax
The intensity range between LT1/VT1 and LT2/VT2 serves as the foundation for this five-zone system, identifying Zone 3 in the model. Thus, the five zones can be visualized as follows:
This detailed classification of intensity zones facilitates clearer communication between coaches and athletes regarding training prescriptions. Low-intensity training (LIT) sessions are generally recommended at approximately 55–70% of HRmax, while high-intensity training (HIT) is typically performed between 87–92% of HRmax (Zone 4), aiming to stabilize around 90% of HRmax. Moderate-intensity training (MIT) falls between these ranges, around 85% of HRmax, and is often termed "threshold" training. For the remainder of this article, I will utilize the five-zone model when discussing various intensity zones.
Polarized Intensity Distribution
I have previously written extensively about polarized training and its practical application, so I will provide a brief overview here. Essentially, polarized training involves dedicating around 80% of total training sessions to low intensity (below LT1) and 20% to high intensity (at or above LT2). In simple terms, keep easy sessions easy and hard sessions hard, but not excessively challenging. This corresponds to approximately 55–75% of HRmax for easy sessions, with a Rate of Perceived Exertion (RPE) of 2–4 (where 0 represents sitting down and 1 indicates walking). High-intensity training sessions should be conducted at 87–92% of HRmax, with an RPE of 7–8, depending on the focus, duration, and type of session.
In a classic polarized training approach, only a small fraction of total training time is spent in the "middle zone" or at moderate intensity (zone 3). However, this does not mean that zone 3 should be entirely avoided. Long threshold sessions can be taxing and may become excessively strenuous if prolonged. Consequently, zone 3 sessions tend to shift towards zone 4. Additionally, whenever an athlete engages in a HIT session, they will inevitably pass through each zone up to the targeted session intensity, with heart rates also descending through the threshold zones during recovery. For instance, in a workout consisting of four intervals of eight minutes each, the initial interval is typically performed in zone 3.
Moreover, in a polarized training model, HIT sessions are less frequent within a week, often featuring 2–3 easy days in between, but with greater volume and total load for each session. A typical training week might look like this:
- Monday: Easy
- Tuesday: Hard
- Wednesday: Easy
- Thursday: Easy
- Friday: Hard
- Saturday: Easy long session
- Sunday: Rest
The practical execution of the polarized model differs from The Norwegian Model, which emphasizes frequent interval sessions conducted at "threshold" intensity. It's crucial to understand the interpretation of "threshold" in this context. If we define threshold intensity based on lactate responses during steady-state running, the well-known "double threshold" sessions are often conducted at a pace significantly above the threshold. However, these sessions consist of shorter intervals at a higher pace with relatively brief work periods to manage blood lactate levels.
Threshold Intensity Distribution
The term threshold is utilized in various contexts, and a universal definition seems elusive. Typically, scientists describe threshold as the "comfortable uncomfortable" effort sustainable for about an hour, or a half marathon for well-trained endurance athletes. For less aerobically conditioned individuals, the threshold may be around 75–80% of VO2max, while elite athletes can reach as high as 90–92% of VO2max.
In a conventional threshold TID model, most training volume occurs at moderate intensity or zone 3. This means that athletes often train at a similar intensity day after day, neither too hard nor too easy. This pattern is common among beginner runners who, lacking experience or an understanding of intensity zones, tend to maintain a pace that "feels" like training. The "runner's high" often encourages them to keep returning for more, at least until they face injuries.
Threshold training can be effective for untrained individuals for a limited time, but stagnation will occur once a certain fitness level is reached. The body requires variation in training stimuli. Even beginners can benefit from alternating between easy and hard training days, pushing the system during high-intensity efforts while allowing for adequate recovery. Furthermore, both intensity and duration should be used as training stimuli, which is best achieved by combining longer low-intensity sessions with shorter, higher-intensity workouts throughout the training week.
Aerobic vs. Anaerobic Threshold
One key lesson I learned from my father, Stephen Seiler, is that the terms aerobic and anaerobic threshold can be misleading. We don't simply shift from aerobic to anaerobic metabolism at a specific intensity. As we increase intensity, the anaerobic contribution grows, and during short sprints, we primarily rely on immediate ATP and Creatine Phosphate. However, approaching the "anaerobic threshold" still involves the aerobic energy system producing ATP. Therefore, terms like the first and second lactate turn point (LT1 and LT2) are more appropriate. At the first point, blood lactate rises from resting levels (~1.5 mmol) to above 2 mmol, entering zone 3 in the five-zone model, with an RPE of 5-6 on a scale of 1-10. At the second point, blood lactate exceeds approximately 4 mmol and continues to rise sharply if the intensity remains constant. This second point defines "threshold," indicating the highest effort sustainable for a reasonable duration without significant increases in blood lactate, heart rate, or breathing frequency.
Thus, LT2 represents the maximum effort maintainable for a considerable time without the need to slow down.
Double Threshold Sessions
A concept popularized in The Norwegian Model is double threshold sessions. The premise is that more "quality" volume can be achieved in a single day by conducting two shorter interval sessions instead of one longer session. This method also reduces the number of "hard days" per week by doubling up on sessions. The applicability of double threshold training ultimately hinges on one question:
> Are you currently engaging in such extensive volume during interval sessions that the only way to gain additional stimulus is by adding another session on the same day?
For most, the answer is NO. Unless you are an elite athlete seeking marginal gains at the top level, it is often more beneficial to extend the duration of high intensity within a single daily interval session.
Why Jakob Ingebrigtsen's Threshold Sessions Differ
Jakob Ingebrigtsen's threshold sessions are significantly different from those of less trained individuals, even at the same relative intensity. When Jakob performs threshold 400-meter repeats, he maintains a notably fast pace, resulting in high internal intensity and mechanical load. In contrast, a less trained runner's 400-meter threshold repeats will be at a significantly lower pace, internal intensity, and mechanical load, but with higher lactate levels! Jakob likely operates at around 90% of VO2max during many of his threshold workouts, while the recreational athlete may only reach 75% of VO2max at their respective threshold. This discrepancy partially explains why threshold training based on specific lactate levels and/or heart rate is less effective for less fit individuals compared to elite athletes.
So, why is there a strong emphasis on not running interval sessions *too hard* in The Norwegian Model?
The stimulus from threshold workouts is substantial for elite runners, and due to the high mechanical load during these sessions, they cannot regularly exceed the threshold in training, both mechanically and metabolically. In contrast, beginner and less trained runners do not experience the same metabolic flux or speed during threshold work. Therefore, they are likely to benefit more from 1-2 high-intensity workouts each week that specifically target the glycolytic pathway. As their threshold improves, they will be able to run faster for longer durations at the same relative intensity. Over time, the length of interval sessions can increase, or an additional weekly interval session can be integrated into their training plan.
The Norwegian Model in Practice
In 2021, I relocated to Oslo and joined a local club known for its adherence to The Norwegian Model, particularly its focus on threshold training. Having trained with a polarized approach since my running journey began and enjoying success with it, I was initially hesitant about this new style of training. However, I decided to give it a try. Unfortunately, it did not yield favorable results for me, culminating in a femoral bone stress reaction before my season even commenced. The shift in mechanical load exceeded what my body could manage, despite my high training volume. I was not alone; several other runners experienced injuries while trying to make a similar transition. Despite the negative outcome, I gained valuable insights and now possess both theoretical and practical knowledge regarding the two training methodologies.
Typical training week during the base season (October — March):
- Monday: Easy run AM, easy run PM
- Tuesday: Double threshold (4x6min AM, 20x400m PM)
- Wednesday: Easy run AM, circuit strength training PM
- Thursday: Easy run AM, 10x1000m PM
- Friday: Easy run AM, easy run PM
- Saturday: 20x200m hills AM
- Sunday: Long run
I noticed numerous flaws within this training structure and felt the repercussions on my body. I sustained an injury and experienced overtraining. Nevertheless, my experience represents only n=1, and I cannot extrapolate it to the overall validity of the model itself. However, injury rates among athletes in Norway are notably high. Apart from Jakob Ingebrigtsen and a few other male runners, the model has not achieved significant success (i.e., at the international level) for the vast majority of athletes in Norway. We currently have only a handful of male distance runners on the global scene and just one female runner in contention. Unlike innovations in Formula 1 that eventually benefit everyday vehicles, this training model seems less applicable to the broader running populace.
The Formula 1 Innovation That Doesn't Scale Down
From a physiological standpoint, two major concerns with the Norwegian model exist: 1) insufficient recovery time between intervals, and 2) frequent "threshold sessions" can impose considerable mechanical stress on bones and surrounding structures, increasing the risk of tendon and bone injuries over time if progression is not gradual.
The Norwegian Model posits that because interval sessions are conducted in a "controlled" manner (i.e., zone 3), athletes can engage in more of it more often, requiring less recovery. This perspective contrasts with Stephen Seiler's assertion that even at moderate intensity, athletes cross their first threshold or LT1, triggering a sympathetic response (the body experiences stress). Therefore, a zone 3 session, akin to a zone 4 session, necessitates considerable recovery time and should be deemed a "hard" training stimulus. Naturally, the duration of the session must always be factored into the overall load.
Ultimately, a zone 3 session does not elicit the same adaptive response as a zone 4 session. Consequently, you gain less value from training at a slightly lower intensity (while still crossing LT1) but still require a similar recovery period. To illustrate, it's like starting a car and revving the engine without fully pressing the accelerator — you must still allow the engine to cool before starting again.
Even if metabolic demands are not severely taxed, shorter intervals at a higher pace and lower lactate levels can impose significant mechanical stress on bones. This is where the situation becomes intricate. Athletes monitor lactate levels to avoid running "too hard," but when interval durations are shortened and sufficient rest is provided, lactate levels drop quickly. In contrast, the mechanical impact is considerably higher compared to longer intervals. Consequently, blood lactate offers limited insights into total session load; it merely reflects how efficiently lactate is cleared during that specific workout (and is influenced by diet, recovery status, etc.). As such, using lactate as a reliable tool for assessing session load is flawed. Neglecting mechanical load can lead to tendon and bone issues if recovery needs outside of training are unmet.
Moreover, as previously noted, elite runners will conduct their threshold sessions at higher relative intensities than recreational athletes. At 3 mmol blood lactate, the less fit runner's pace and heart rate will be significantly lower, resulting in a session that may not feel particularly challenging. When interval workouts become "too easy," there is a heightened risk of many easy runs becoming overly strenuous, pushing athletes closer to the middle-intensity zone on most days. This shift can quickly lead to a muddled approach, blurring the distinctions between easy, moderate, and hard efforts, thereby skewing the overall intensity distribution toward "threshold."
Is There an "Optimal" Training Intensity Distribution Model?
Years of research indicate that elite endurance athletes typically allocate around 80% of their training sessions below LT1, with about 20% at or above LT2 (90% of total training time < LT1, 10% of total training time ? LT2). While "threshold training" is often associated with The Norwegian Model, the actual intensity distribution does not align with the concept of 'threshold.' Elite athletes who thrive under this model still spend most of their total training time below LT1, engaging in easy running at low heart rates and RPE. At threshold lactate levels, they will still operate at around 90% of VO2max. Therefore, I would argue that their training might resemble a pyramidal approach during the base season (more time in high zone 3 and low zone 4) and a polarized method during the peaking phase, when race pace work increases and overall volume decreases (less time in zone 3 and more in zones 4-5). However, as mentioned earlier, recreational athletes following The Norwegian Model risk gravitating toward the middle zone too frequently if they lack intensity discipline, rendering this model less effective for sustained progress.
Regardless of the intensity distribution model adopted, the training process ultimately revolves around two interacting variables: volume and intensity. How athletes blend these variables is less important than ensuring consistent training, maintaining health, and fostering sustainable progress over time.
In summary, I contend that The Norwegian Model does not provide sufficient recovery between interval sessions, potentially leading to physical strain and performance stagnation in the long run. In contrast, a polarized approach allows ample rest between HIT sessions, facilitating numerous hours of LIT work that enhance the oxidative pathway, while sparingly incorporating high-intensity sessions that effectively target the glycolytic pathway. This combination maximizes adaptive signaling at the cellular level. When easy days remain genuinely easy, athletes can push hard during interval sessions without fear of lactate levels exceeding 4 mmol, as it is the high mechanical load that causes post-training soreness, not the lactate itself!
Final Thoughts
As a practitioner and student of endurance training and its underlying physiology, I coach athletes with a polarized intensity approach and adhere to these principles myself. However, I do not claim that this is the only effective training model! Various training frameworks are essentially distinct ways of managing total training load. Load = intensity x duration. When increasing training volume, one should not simultaneously ramp up intensity. Likewise, as intensity increases in the lead-up to a significant race, overall volume must decrease to allow for recovery between critical sessions. It’s all about striking a balance between energy output and intake. A well-structured equilibrium of frequency, volume, and intensity often results in improved performances and training progress.
Ultimately, it is up to each individual to determine the best way to solve this equation for themselves.
Key Takeaways: Fundamentals of a Sustainable Training Process
- Build low-intensity volume and frequency before introducing intensity.
- Increase your threshold over time before adding another interval session. You earn the ability to train harder more frequently by improving fitness.
- Avoid blending your training — keep low-intensity days separate from high-intensity days. Excessive training at "threshold" (zone 3 for less trained runners) can yield quick progress initially, but will also lead to stagnation if the training stress becomes repetitive. You won’t recover adequately, nor will you reach the high intensities required for optimal adaptations.
- Avoid imitating the training of others, especially top athletes. Their approach is often tailored to years of experience and may not suit your needs.
- Remember, in your training journey, n=1. Compare your progress solely to yourself. Exercise patience and trust the process.
- Lastly, acknowledge that your needs and capacities change over time. What worked well for you two years ago may not be as effective today. Adapt and modify your approach as necessary.
There is no one-size-fits-all recipe for successful training. Engage with research, learn from accomplished athletes, heed expert advice, but most importantly, become an expert on your own body and how it responds to training.
The secrets to an effective training process include: 1) determining a sustainable volume for yourself, 2) applying high-intensity sessions judiciously, and 3) LISTENING TO YOUR BODY — responding to its signals.
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I offer coaching services for runners, cyclists, and triathletes of all levels, from beginners to highly competitive athletes. If you're interested in full-time coaching, a personalized training plan, or a one-time training analysis, please reach out via email at [email protected]. For more information, visit my website: https://sirenseilercoaching.wordpress.com/.