Shownotes

Training background and career overview

01:42 -

• I specialised in the 1500 metres, though I was also competitive at 800 metres. My professional career ran from 2003 to around 2015 or 2016, with the peak of it culminating in the European Championship title in 2010.
• The training we did back then was typical of the era, but it came with significant limitations — we had no GPS, no smart watches, and heart rate monitors were not standard practice, so our ability to monitor and control training load was quite limited.
• In terms of volume, I was working through roughly 120 to 170 kilometres per week depending on the time of year, with the competitive period naturally bringing that down.
• The structure included three high-intensity sessions per week, with the remaining days composed of continuous running — some threshold work mixed in, but mostly what was supposed to be easy or moderate aerobic work.
• The main thing I would change, knowing what we know now, concerns intensity distribution. On the days that were meant to be easy, they often were not.
• We regularly pushed above the first lactate threshold when we should have stayed well below it. This was not a mistake unique to me — it was common across middle-distance running at the time — but it had real consequences.
• Injury rates were high, overreaching was frequent, and a lot of that came down to the easy days simply not being easy enough.
• The session structure itself followed a fairly clear periodised pattern: VO2 max intervals, one session per week targeting second-lactate-threshold intensity, and one anaerobic capacity session. That framework changed depending on where we were in the season, but that was the general shape of things.
• The top runners from my era, Hicham El Guerrouj, who still holds the world record, were simply exceptional, and the record has not fallen despite advances in training methodology and shoe technology.
• That said, looking at average performance across the field tells a different story. There are now around 30 athletes per year running under 3:30 for the 1500, which was almost unimaginable 20 years ago.
• That kind of depth reflects a genuine improvement, and I think a meaningful part of it comes down to exactly the issue I mentioned — athletes now actually run easy on their easy days.
• That shift in how intensity is distributed across the training week has had a substantial impact on performance at the middle-distance level.

Training intensity distribution: concepts and context

8:44 -

• Training intensity distribution refers to the percentage of total training volume conducted across different intensity domains or zones.
• It is one component of training, not the whole picture, and this distinction matters.
• If you have a marathoner covering 200 kilometres per week with 80% of volume below the first lactate threshold, 10% between the two thresholds, and 10% above the second, and a middle-distance runner doing 100 kilometres per week with exactly the same percentage split, those are two fundamentally different training regimes.
• The volume is double in one case. So training intensity distribution cannot be read in isolation — it must always be considered alongside volume.
• The other major component to understand alongside intensity distribution is periodisation, which in endurance sport refers specifically to how training intensity distribution and volume evolve and change across a season.
• Together, these two variables give you a meaningful picture of what an athlete is actually doing.
• There is a study by Berlinger and colleagues that tested three different methods for analysing training intensity distribution in highly trained middle-distance runners over roughly ten weeks: RPE relative to both lactate thresholds, speed relative to both thresholds, and heart rate relative to both thresholds.
• Each method produced a different intensity distribution pattern for the same training content.
• This confirms the problem precisely: heart rate, for instance, lags behind actual effort and will underestimate high-intensity work, while pace or speed can overestimate time at a given zone depending on warm-up structure.
• The practical takeaway from this, though, is not to get too absorbed in the limitations of each method. What matters most is consistency: using the same method over time, so that comparisons across periods of a season, or across seasons for a given athlete, are actually valid.
• The other lesson is methodological when reading research: never rely only on the abstract. Go to the methods section and establish how training intensity distribution was measured, because the interpretation of results depends entirely on that.

The polarisation index and training models

16:10 -

• The polarisation index is essentially a tool for determining whether a training period has followed a polarised model or not.
• The limitation is that polarised is just one of several models. It does not account for pyramidal or threshold-based approaches, and that matters because current research is consistently finding that the pyramidal model outperforms the polarised model across most endurance sports. 
• The index has practical utility, but it gives an incomplete picture of what is actually happening in a training block.
• There are now multiple systematic reviews across different sports addressing this question — in runners, swimmers, cyclists, and rowers.
• The consistent finding across all of them is that both the pyramidal and polarised approaches are the most effective training intensity distribution patterns for improving performance and its physiological determinants.
• There are exceptions — sprint swimmers, for instance, tend to make more use of a threshold-based approach — but in the majority of sports and studies, pyramidal and polarised come out on top.
• The more nuanced and arguably more important finding concerns how these models interact with periodisation across a season.
• What the research points to fairly consistently is that beginning the general preparation period with a pyramidal distribution and progressively shifting towards a polarised approach during the competitive phase tends to produce the best results.
• This is, in many respects, a formalisation of what traditional periodisation in endurance sport has looked like in practice.
• A well-designed study by Luca Philippas and colleagues illustrated this clearly. They worked with a group of highly trained recreational runners averaging a VO2 max of around 68 millilitres per kilogram per minute — a genuinely impressive sample.
• The group that followed eight weeks of pyramidal intensity distribution followed by eight weeks of polarised distribution showed the greatest performance improvements and the best physiological adaptations. That is essentially where the literature stands in 2026.

Periodisation for different events and athlete levels

22:13 -

• The pyramidal-to-polarised periodisation pattern holds well for events from 800 metres up to half marathon, but the marathon is a genuine exception.
• Working closely with Australian coach Nick Bido and publishing several papers using his athletes, we found that marathoners typically follow a reverse periodisation pattern — training intensity decreases in the ten to fifteen weeks before the race while volume reaches its peak, before tapering in the final three weeks.
• That inversion makes physiological sense given the demands of the event.
• For amateur runners targeting a half-marathon at around 90 to 105 minutes, reverse periodisation can also be appropriate, for a different reason.
• Their overall training volume tends to be lower, which limits how much they can increase it meaningfully.
• Additionally, their race pace sits comfortably below LT2, so the relative intensity of competition is not high enough to require the same level of preparation specificity as an elite athlete. In that context, front-loading some higher-intensity work early in the season is a reasonable approach.

Intensity within zone one

26:10 - 

• There is currently no interventional research that differentiates between intensities within zone one — the low-intensity domain in the three-zone model — so any answer here draws on experience rather than hard evidence.
• What I observed during my time training and competing, including alongside Kenyan runners, is that the better and higher-volume the athlete, the slower the easy runs tend to be.
• Kenyan athletes run genuinely slowly on recovery days compared to many European runners, and that seems to matter. The higher the weekly volume, the more reason there is to keep zone one work towards the lower end of that range.
• Marathoners tend to run their easy days easier than 1500-metre runners, and that pattern holds across the sport.
• When overall fatigue is high — whether from running volume alone or from a triathlon training load combining swimming, cycling, and running — there is good reason to err on the slower side. 
• For athletes training at lower volumes who are not accumulating the same fatigue, staying closer to the upper boundary of zone one is less problematic.

Tailoring training distribution to athlete's level

30:10 -

• One of the clearest practical findings from the research is that elite athletes operate within a much narrower window of effective training approaches.
• In our work on training intensity distribution in elite runners, only pyramidal and polarised approaches consistently drove improvement.
• In a systematic review we currently have under review on recreational runners, the picture is quite different — many different training intensity distribution patterns produced positive results.
• At lower performance levels, almost any well-applied stimulus will generate adaptation, which gives coaches considerably more flexibility in their approach.
• A 2025 systematic review with meta-analysis by Rosenblatt and colleagues added an interesting nuance: among elite endurance athletes, the polarised approach appears marginally more effective than the pyramidal model, while in recreational athletes the relationship reverses.
• One plausible explanation is that higher-level athletes can physiologically tolerate greater high-intensity loads — though this has not been our consistent finding in runners specifically.
• The broader principle is straightforward: recreational athletes can use a wider range of training philosophies effectively, provided the components of training load are managed well.
• For athletes with limited time to train, it may make sense to reduce volume and shift intensity upward slightly.
• The constraint of fixed training time is one of the most practically relevant factors when deciding how to distribute intensity across a week.

Training intensity distribution across sports

34:40 - 

• Looking across the three triathlon disciplines and beyond, the research reveals some sport-specific patterns worth understanding.
• In swimming, the pyramidal model tends to be more effective for long-distance swimmers, while the polarised model suits sprinters and middle-distance swimmers better.
• In cycling, the pyramidal approach is generally more effective at elite level. In rowing, both pyramidal and polarised approaches outperform other models, which mirrors what we find in running.
• Within running specifically, a case study we conducted alongside the broader systematic review compared 1500-metre runners and marathoners directly.
• Marathoners completed a higher proportion of their training volume in zone two — between the two lactate thresholds — which makes sense given that marathon race pace falls within that zone.
• The 1500-metre runners had a lower relative contribution from zone two but a higher one from zone one.
• That said, in absolute terms the marathoners were still covering more volume in zone one; the relative percentage was lower simply because their total volume was so much greater.

Take-home messages on training intensity distribution

38:05 - 

• One message applies to all athletes regardless of level: measure your training intensity distribution, track how it changes across the season and from one season to the next, and use that information to understand the relationship between what you are doing in training and how you perform in races and physiological tests.
• Without that reference point, you have no basis for making informed decisions about how to adjust your training. Volume and intensity distribution are the core variables — if you are not measuring them, you are largely guessing.
• The starting point has to be testing. Relying on smartwatch-generated training zones is not sufficient — those metrics are not truly individualised, despite appearing to be.
• At a minimum, athletes should invest in two or three physiological tests per season to track how key performance determinants are evolving and to set accurate, individualised training zones.
• Without that, the intensity distribution you think you are following may bear little relation to reality.
• For the measurement method itself, heart rate is not ideal — but for an uncoached athlete it is far more objective than RPE-based approaches and remains a reasonable practical choice.
• The critical thing is to use it consistently. And beyond all of this, having a coach makes a substantial difference — someone who can interpret the data and make informed adjustments is genuinely valuable, and I would strongly recommend it to any athlete who can access that support.

Testing methods for zone determination

41:10 - 

• The choice between gas exchange testing and lactate testing matters less than consistency.
• Either method is valid, but switching between the two, or changing devices or the person administering the test, makes season-to-season comparisons unreliable. Pick one approach and stick with it.

Training models — Lydiard

42:08 -

• Arthur Lydiard is, in my view, the father of modern periodisation in endurance sport.
• His model was built around a long preparatory period of predominantly continuous running, during which athletes developed their aerobic base and progressively raised the speeds associated with their lactate thresholds.
• This was followed by a hill training phase that introduced some higher-intensity work, and then a competitive preparation phase of high-intensity interval training at race pace.
• What I find remarkable about Lydiard is how well his athletes avoided overtraining, the extended base period insulated them from it, and how sharply they peaked for their main competition.
• The absence of high-intensity interval training during the base phase meant athletes could train at moderately higher intensities during their continuous runs without accumulating excessive fatigue, which in turn helped them raise threshold speeds.
• The peaking phase was also distinctive: athletes sometimes completed four, five, or even six high-intensity sessions in a single week, which would be unsustainable without the aerobic foundation built over months of high-volume, lower-intensity work.

Training models — The Kenyan model 

45:00 - 

• The Kenyan model is characterised, above all else, by the absence of formal periodisation and by the extreme contrast between easy and hard sessions.
• The high-intensity workouts are genuinely all-out — athletes train in groups that often include some of the best runners in the world, which means the sessions become effectively competitive.
• The workout volumes at high intensity are not especially large for middle-distance runners, though for marathoners the long run — sometimes 40 kilometres at close to marathon pace, performed every other week — is extraordinary.
• What I found in my PhD research comparing Kenyan and Spanish runners was that the Kenyan model also includes a meaningful amount of tempo running, something European and North American runners were largely neglecting 15 to 20 years ago.
• When you measure it, the overall distribution ends up being pyramidal.
• The defining characteristic, though, is the polarity of effort within sessions: the easy runs are genuinely very easy, and the hard sessions are extremely hard. 
• The recovery capacity this creates — combined with high-altitude training in the hilly Rift Valley, typically above 2,000 metres — is what makes such demanding training sustainable across a season.

Training models — The Canova model

47:50 - 

• Conceptually, I find the Canova model interesting, but in practical terms I have reservations about the training load it imposes.
• The model is built around blocks of high-intensity training in which very hard sessions are placed close together, while overall volume remains high simultaneously.
• Athletes do recover between blocks — not in a single day, but over two to four days — and that recovery window seems to be sufficient to sustain the approach.
• An example of such a block might involve high-repetition 1000-metre efforts at very high intensity in the morning followed by a tempo run in the afternoon, with another hard session the following morning. 
• From what I understand from others who have worked with Canova, marathon-specific blocks can involve two long hard sessions in a single day — one morning, one afternoon — accumulating well above 30 kilometres at marathon pace. That is an exceptional load by any measure.
• The other defining characteristic of the model is the progressive funnelling of intensity from general physiological work in the early phases towards highly race-specific work later in the preparation, approaching target race pace from both above and below.
• That concept makes sense — it mirrors in some ways what Lydiard was doing intuitively, without the physiological measurement tools we now have.
• What I think deserves emphasis regardless of the model, though, is that running carries a mechanical load that other endurance sports do not.
• The consequences of excessive training load in runners can be severe, and that warrants real caution whenever load is pushed high.

Injury risk — volume, intensity, and load changes

50:54 -

• Both volume and intensity contribute to injury risk, and very high training loads — however they are generated — increase that risk substantially.
• But the factor I think matters most, and which the research by Gabbett and colleagues has examined extensively despite some criticism, is the change in training load rather than the absolute level.
• Acute spikes relative to chronic load are the primary driver of injury, and that relationship holds whether load is rising through increased volume or increased intensity.
• The practical implication is that monitoring the acute-to-chronic workload ratio is genuinely useful — not training intensity distribution specifically, but overall training load measured through something as simple as session RPE multiplied by duration, or through more sophisticated metrics.
• If you track that consistently and manage week-to-week changes carefully, you can control injury risk with a reasonable degree of accuracy.
• That is, in my view, the single most actionable variable when it comes to keeping athletes healthy.

Training models — The Norwegian double threshold model

54:04 -

• What I find genuinely original about the Norwegian model is that it shifts the focus away from pace and towards physiological response.
• Rather than targeting a given speed during interval sessions, athletes monitor their lactate continuously and aim to keep it within zone two — between the two lactate thresholds — throughout the workout.
• If lactate rises above the target level after a repetition, pace is reduced on the next one to bring it back into range. The goal is to maximise the mitochondrial stimulus during each session without crossing into heavy glycolytic territory.
• Four sessions per week are structured this way, with lactate measured throughout, and a fifth higher-intensity session provides the anaerobic stimulus that the threshold work deliberately avoids.
• Without that higher-intensity session the model would be incomplete, but the core innovation is the lactate-controlled interval work, which generates strong aerobic adaptations through accumulated volume at a tightly managed physiological intensity.

Training models — The Melbourne track club model (Nick Bido)

58:00 - 

• This is a model I know well from having collaborated on four published papers using athletes from the group.
• What I admire about it is that the overall training load is not particularly high, yet the performance outcomes consistently are.
• Volume runs from around 120 to 170 kilometres per week for track runners and up to roughly 200 for marathoners, but the structure is straightforward and largely unchanged across the season — including during the competitive period, where volume stays high rather than dropping.
• The week typically contains three quality sessions. Tuesday might be eight times one kilometre just above the second lactate threshold with short recovery — around one minute of jogging — which keeps the pace honest without allowing it to become a VO2 max effort.
• Thursday is a threshold run of eight to ten kilometres, with heart rate used to control pace, echoing the physiological monitoring principle of the Norwegian model. 
• The third session, often on a hill, targets VO2 max — something like six times 800 metres with a jogging recovery back down.
• A long run on Sunday completes the week. It is a classical structure, but applied with discipline and consistency over many years, and the results speak for themselves.

Practical lessons for amateur runners and triathletes

1:02:07 - 

• The most important message from all of these models, for recreational athletes, is to focus on the basics and do as little as necessary to achieve the maximum adaptation possible.
• Different training approaches work for recreational athletes — the research confirms that flexibility, so there is no need to follow a rigid elite model. The more important constraint is recovery.
• Elite athletes spend the majority of their day resting; training is a small part of the 24 hours and recovery is the largest.
• Recreational athletes who work full-time and carry other responsibilities simply cannot replicate that recovery environment, and trying to match elite training loads without elite recovery capacity is a reliable path to injury or stagnation.
• When in doubt, doing a little less often works better than doing more.
• On the question of session frequency, three quality sessions per week as used in the Melbourne Track Club or Norwegian models is too much for most amateur athletes.
• Two quality sessions per week is a more appropriate target — one focused on developing speed at the second lactate threshold, such as a tempo run or threshold interval session, and one targeting VO2 max at a higher intensity.
• That combination provides the necessary physiological stimulus without the recovery demands that a third hard session would impose.

VO2 Max development and the role of high intensity for amateur athletes

1:07:50 - 

• There is a genuine misunderstanding among many recreational athletes about what a pyramidal training intensity distribution actually means. When research finds that the pyramidal model works well for amateur athletes, it does not mean they should avoid high-intensity work. y
• Pyramidal simply means that a small percentage of overall volume is conducted at high intensity — but that small percentage still represents at least one genuine high-intensity interval session per week.
• What recreational athletes cannot tolerate is a high volume of high-intensity training. The intensity itself is still necessary.
• The Norwegian model illustrates this clearly. One of its key sessions involves something like 20 times 200 metres on a hill at near-maximum effort, with lactate reaching around 10 millimoles per litre.
• That session is not optional — without it, the rest of the training would not produce the same results. Doing only threshold work and never reaching high intensity is a significant omission.
• The practical adjustment for recreational athletes is not to eliminate high-intensity sessions but to reduce their volume.
• Where an elite runner might complete eight kilometres of high-intensity repetitions in a single session, a recreational athlete might do five repetitions instead of eight at the same relative effort.
• The intensity of the stimulus is preserved; the volume of it is scaled to what they can absorb and recover from.
• That distinction — between the intensity of the work and the volume at that intensity — is one of the most important things for amateur athletes to understand when designing or evaluating their training.

Marathon pacing strategies

1:10:50 - 

• Research on marathon pacing shows a clear historical evolution. In the 1980s and earlier, world record performances were characterised by positive splits — athletes went out fast and slowed progressively. 
• Over time that pattern shifted, and more recent world records have been set with even or negative pacing profiles, where the second half is run faster than the first.
• It is worth noting that this shift coincides closely with the introduction of the super shoes, for which there is good evidence that the primary benefit is a reduction in muscle fatigue in the later stages of the race — which mechanically explains why athletes are now able to maintain or increase speed in the second half.
• Looking at the new world record set by Sabastian Sawe in London — with a first half of 60:29 and second half of 59:01 — my reading is that the gap between the two halves is larger than optimal.
• For events where the overwhelming majority of energy comes from the aerobic system, the most mechanically efficient pacing strategy is an even split.
• The SUB2 project understood this well: when Kipchoge first broke the two-hour barrier in an unofficial setting, the pacing was deliberately kept as even as possible across the entire race.
• Sawe is clearly capable of running faster than he did — which is a remarkable thing to say about a world record — but an even more controlled first half would likely yield a faster overall time.
• The approach differs considerably depending on performance level.
• For elite athletes competing in major marathons, the context largely dictates pacing — pacemakers are assigned, their target splits are known the day before, and the drafting benefit of staying within a group outweighs the value of fine-tuning pace based on internal signals.
• In that environment, RPE and heart rate are secondary to race dynamics.
• For recreational runners the situation is quite different. The field density means drafting benefit is available regardless, and in that context I think the most practical approach is to race primarily by RPE.
• The reason is that RPE is integrative — it captures not just lactate accumulation but hydration status, heart rate, muscle fatigue, environmental conditions, and psychological state, all within a single perceived number.
• Lactate measurement gives you one variable; RPE gives you everything at once. The key is to practise using the Borg scale consistently in training so that specific feelings become familiar and reliable.
• Athletes who do that can transfer those calibrated sensations directly into race pacing, and that familiarity is what makes RPE genuinely useful rather than vague.

Final advice for amateur runners

1:19:00 - 

• Two things stand out as underutilised by most recreational runners.
• The first is strength training. Its impact on running economy is substantial and well-supported by evidence, and while the literature is not entirely conclusive on injury prevention, I believe that a consistent strength training programme reduces injury risk meaningfully. 
• It is one of the highest-return investments an amateur runner can make.
• The second is simply not trying to replicate elite training. The difference in lifestyle is fundamental — elite athletes spend the majority of their day recovering.
• Training is a small fraction of their waking hours; everything else is structured around rest and adaptation.
• Recreational athletes who work full-time and carry other responsibilities cannot replicate those recovery conditions, and attempting to match elite volumes or intensities without that recovery infrastructure leads reliably to overtraining or injury. 
• The benchmarks from our systematic review on recreational runners suggest that most are training somewhere between 50 and 80 kilometres per week, depending on their level, with marathoners sitting somewhat above that range.
• Those figures provide a useful reference for what is appropriate and sustainable.

Visiting Madrid

1:21:35 - 

• For anyone visiting Madrid, my sport-related recommendation is the Casa de Campo park, a large green space very close to the city centre where most elite runners and triathletes in the city train.
• The loop known as La Tapia runs approximately 18 kilometres and is suitable for both running and cycling — it is a genuinely beautiful route and well worth the visit.
• On the non-sport side, the Prado Museum is one of the finest in Europe, with an exceptional collection spanning the 16th to 19th centuries.
• Immediately adjacent to it is Retiro Park, another of Madrid's great green spaces where you can run or simply walk. The two together make for an excellent afternoon in the city.

LINKS AND RESOURCES

• Arturo’s ResearchGate, Instagram and World Athletics profiles 
• Effects of polarized, pyramidal, and combined training periodisations with Luca Filipas, PhD | EP#328 - study mentioned in the interview
• Michele Zanini (part 2) | EP#394 - the Renato Canova training method
• Training Periodization, Methods, Intensity Distribution, and Volume in Highly Trained and Elite Distance Runners: A Systematic Review Casado et al. 2022
• Training Periodization, Methods, Intensity Distribution, and Volume in Highly Trained and Elite Distance Runners: A Systematic Review Casado et al. 2022
• World-Class Long-Distance Running Performances Are Best Predicted by Volume of Easy Runs and Deliberate Practice of Short-Interval and Tempo Runs - Casado et al. 2021
• Does Lactate-Guided Threshold Interval Training within a High-Volume Low-Intensity Approach Represent the “Next Step” in the Evolution of Distance Running Training?- Casado et al. 2023
• Pacing strategies in men's and women's world- record marathon performances and Olympic Games and World Championship's winning performances - Casado et al. 2024
• Training Intensity Distribution, Volume, Periodization, and Performance in Elite Rowers: A Systematic Review - Zhong et al. 2025
• Which Training Intensity Distribution Intervention will Produce the Greatest Improvements in Maximal Oxygen Uptake and Time-Trial Performance in Endurance Athletes? A Systematic Review and Network Meta-analysis of Individual Participant Data - Rosenblat et al. 2025