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Tag: Zone 2 training

  • Long Drive, Good Thinking

    Long Drive, Good Thinking

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    “Volume still matters, but high intensity shouldn’t dominate either,. It needs to be precisely controlled and well separated from endurance work to allow recovery and adaptation.” —Jim Galanes.  (Photo:  Manzoni/NordicFocus)

    Over the last six days, I drove 1,000 miles down to Tucson and 1,000 miles back to visit Bob Treadwell, a teammate on the U.S. Ski Team in the mid-’70s, along with our friend Tim Caldwell, who most readers will know from his long run on the U.S. Ski Team from the 1972 Olympics in Sapporo through Sarajevo in 1984. We had some fun days reminiscing, telling lies, and remembering the old days.

    Over 2,000 miles of driving gave me plenty of time to listen to podcasts, Andy Newell’s, FastTalk Labs, and The Science of Sport. Most were excellent: informative, thought-provoking, and occasionally challenging in a good way. I encourage anyone with time and curiosity to dig into some of these.

    After dozens of hours listening to topics ranging from adaptive signaling pathways and Zone 2 training to periodization, “Norwegian” models, AI-driven coaching, and separating bro-science from real science, I was struck by how often what I heard aligned with how I already think about training and by where it pushed me to learn more. All good things. This piece is meant to follow up on my earlier article on holistic training and fill in some of the gaps.

    The Zone 2 Confusion

    There’s no shortage of discussion or misunderstanding about Zone 2 training. What’s often missing is a clear definition of the Zone 2 terminology. In one podcast, for example, the host and guest both discussed “Zone 2” but were talking about different intensities. The guest defined it as anchored at Lactate Threshold 1 (LT1) or Ventilatory Threshold 1 (VT1). The host used a “Norwegian” Zone 2 model that sits above LT1/VT1.

    I use a similar system. My Zone 2 starts above about 72 % of max HR—mostly above LT1/VT1, so what we in skiing call Zone 1 often overlaps with what cyclists and runners call Zone 2. Understanding those nuances matters when listening to these discussions; otherwise, we end up talking past each other.

    What Zone 2 Actually Does

    Zone 2 is discussed as a magic zone, credited with everything from increasing mitochondrial number and function, capillary density, and free-fatty-acid oxidation to improving stroke volume, aerobic enzymes, and cardiac output. All of that is partly true. But all training intensities contribute to these adaptations, it’s just a matter of signal strength.

    Science shows the molecular signaling for most of these outcomes (via PGC-1α, AMPK/p38, etc.) is strongest with high-intensity work. That’s why elite endurance athletes train such high volumes: the weaker adaptive signal from Zone 2 requires a large total load to produce meaningful change.

    That also means juniors, with lower training volumes, won’t see the same aerobic response early on. Volume still matters, but high intensity shouldn’t dominate either. It needs to be precisely controlled and well separated from endurance work to allow recovery and adaptation.

    The BSF Pro Team out for a rollerski during a June 2022 camp in Lillehammer and Sjusjøen, Norway. (Photo: BSF Pro Team)
    The Real Value of Low Intensity

    The growing focus on Zone 1–2 training in cross-country skiing is a good thing. It’s helped younger athletes learn how to train effectively and older skiers build higher volumes with lower risk of overtraining. I wish my generation had understood that paradigm.

    The takeaway,  all phases of the year should include a mix of low and high intensity. The large volume of low-intensity work builds the foundation, fatigue resistance, durability, neuromuscular coordination, and technique economy, that makes high-intensity work effective. As Stephen Seiler says, both low and high intensities belong in the program year-round. I couldn’t agree more. The way I think about it, the high intensity work improves the adaptive response to the low intensity training.

    Threshold and High-Intensity Training

    Threshold and “double threshold” training have become trendy topics lately. Many people, in my view, are copying successful athletes without understanding why it works for them.

    A few key points:

    • The higher the intensity, the stronger the adaptive response, but the dose and density must still allow recovery.
    • Elite athletes often operate above 90 % of VO₂max. Years ago, mine was around 92 % with a VO₂max of 82–85 ml/kg/min. For athletes like that, threshold training often blurs into VO₂max work.
    • Athletes with a low VO₂max need to raise that ceiling before threshold work will pay off. Those already high on both VO₂max and fractional utilization might get more from VO₂max or race-specific intensity instead.

    The load of threshold training is also often underestimated. Jessie Diggins, in a FastTalk podcast, mentioned a session of 5 × 12 minutes at threshold. That’s roughly an EPOC ≈ 275 ml/kg and TRIMP ≈ 135, compared with a typical 30-minute VO₂max workout at EPOC ≈ 250 ml/kg and TRIMP ≈ 100. In real terms, threshold sessions are not necessarily lower stress or easier. Done excessively, they can be just as taxing.

    Beyond energy systems, we also need to train skiing power (peak velocity), pacing ability, technical and tactical skills, and the ability to sustain race pace. Those elements should guide the interval prescription as much as the physiology.

     

    For every athlete, we need to weigh the cost-benefit . . .

                                                                                      Jim Galanes

     

    Testing and Control

    For serious and older athletes, proper lab testing, measuring lactate and ventilation, is ideal to anchor training zones accurately.

    For juniors and masters, I use a simpler field test: a six-minute effort, averaging HR over the final 3–4 minutes to anchor the top of Zone 4 (VO₂max). The bottom of that zone is about 5 % lower. From there, you can estimate the lower zones closely. I set the top of Zone 1 around 72 % HRmax.

    It’s not perfect, but neither is lab testing, given measurement error and day-to-day variation. That’s why zones are ranges, not fixed points.

    EPOC PERFORMANCE TRAINING ZONES-Based on Max HR 200
    Training Zones Percent of MHR Heart Rate Comments La
    Level 1 Aerobic Efficiency Training 60% 72% 120 144 Basic Endurance Work/if using lactate, the top of the Zone is LT1 .8-1.5
    L2 72% 82% 144 164 Cost more than it benefits 1.5-2.5
    Level 3 82% 87% 164 174 Maximal Steady State Used mainly for long race specific training and mature elite athletes 2.5-4
    L4- VO2Max/Race Pace and Intervals 87% 92% 174 184 Top of Zone Confirmed by average HR in 6 mins test.  Low to mid-Level 4 can be as much as 60-90 minutes race efforts for fit athletes. 4-6
    L5-Maximal 92% 98% 184 196 Short Races < 6 mins, Very Hard Intervals 6-10

     

    This Coach’s Perspective

    I typically reserve threshold-focused training for athletes who already have a relatively high VO₂max, high fractional utilization, and/or who are racing very long distances. There’s ample evidence that VO₂max-type training can also drive adaptations at threshold. In practical terms, 15–30 minutes of VO₂max work can produce a similar level of stress needed to stimulate adaptation.

    Even in the best of cases, identifying VT2 or LT2 visually is problematic. The analogy I use is that trying to find that “corner” on a lactate or ventilation curve is like trying to find a corner in a circle, it’s often not there. After looking at years of lab and field tests, I’ve found that for most non-elite athletes, lactate and ventilation tend to rise in a relatively linear fashion, making any precise threshold point more of an estimate than a clear physiological marker.

    For most non-elite athletes, the focus should be on one or two Zone 4 sessions per week. The key point is that heart rate alone does not create the stress necessary to improve VO₂max or velocity at VO₂max. What drives those adaptations is the muscle’s ability to produce higher power or speed outputs.

    For juniors, masters, and athletes new to structured training, I recommend simplifying things into three zones during the early years:

    1. Endurance training – below LT1/VT1
    2. Moderate training – between LT1/VT1 and LT2/VT2
    3. Hard training – above LT2/VT2

    This approach keeps training simple and helps athletes learn how to polarize their effort effectively without getting bogged down in unnecessary complexity.

    Finally, the goal of all high-intensity training is to recruit more motor units and to increase the power or velocity an athlete can sustain over race durations. For every athlete, we need to weigh the cost-benefit: extensive threshold work is metabolically expensive relative to VO₂max training and should be programmed with that in mind.

     

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    Longtime teammates and friends, Jim Galanes, Bob Treadwell, and Tim Caldwell. (Photo: courtesy of he author)

     

     

     

  • Zone 2 Training: the Latest Fad

    Zone 2 Training: the Latest Fad

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    Brian McKeever treadmill training , a controlled environment in which much fitness testing takes place. (CCC photo: flickr.com/photos/cccski)

    In recent years Zone 2 training has become the latest fad. It seems like everyone has a different definition or interpretation of the infamous Zone 2 training. When discussing training zones, it is important to understand a couple of key points. Training zones are typically set up to approximate metabolic anchors but not exact points and some of these anchors may not even exist. Training zones are simply bins where we put training so we can assess the training loads and adaptations to training. When we discuss training zones, we need to understand how the people discussing these zones have established those zones and what they are. We are all usually speaking a different language here.

    Many point to Inigo San Millan’s developmental work in cycling as the origin of Zone 2 training. His work has providing clarity in this space, and I agree, to a point. However, the importance of intensity control in training has been around for a long time, but this renewed focus has provided some needed focus and clarity. For a lot of athletes, we need to make this whole zone conversation clearer and a whole lot simpler. In his previous lab work at CU Boulder, Inigo has arrived at Zone 2 definition based on lactate accumulation rates, peak fat burning (FatMax) and VO2/CO2 kinetics. For most athletes, this level of lab testing is expensive and not readily available. Honestly, without additional field testing, there are no assurances that what one learns in the lab test applies in daily training.

    There are certain predictable benchmarks that Inigo has observed over the years. LT 1 (Lactate Threshold 1) VT1 (Ventilatory Threshold 1) usually occurs at 68-75% of maximum heart rate and a lactate of 2 mm or less. Given the day-to-day variation in these metabolic markers—and variations due to training and recovery status—it seems to me that sophisticated lab testing, while very interesting and nice to assess, may not tell us much more than using general markers that are easily available.

    We know that aerobic threshold can shift a bit day-to-day. The idea that you can precisely anchor it with a fixed lactate number is at best misleading, unless you’re doing frequent spot checks every workout. Here’s a case from a test done in Inigo’s lab at CU. Granted, it’s just one athlete, but I have another test done there on a different athlete that confirmed similar zone definitions.

    In the CU test, Inigo defines Zone 2 between 132–140 bpm. In contrast, I would set aerobic threshold closer to 1.7 mmol with a corresponding HR around 144 bpm. His Zone 2 is where lactate levels are stable—below the aerobic threshold. And frankly, that’s the best definition of Zone 2 I’ve come across. In my experience, that’s the optimal intensity for endurance development. The challenge in defining Zones is how these anchors are determined. In the above lactate example different coaches and physiologists would use different methods. Some would use a fixed lactate level of 2 mmol, which in this case would be about right while others might use an arbitrary point of a .5 mmol increase in lactate above baseline. I wonder why when we try for precision through testing when we use arbitrary anchors? In this case, it is clear to me that LT 1 is right at the top of Zone 2 as Inigo has defined it.

    In a future article we will discuss lactate thresholds, how they are identified and if they really exist. Here’s a hit toward that future discussion: if we were to account for the possible range of error of lactate analyzers—and install error bars on the graph described above—we would be hard pressed to say, in this case and many others that I have seen, that the increase in lactate is in fact linear with the increase in the rate of work.

    Measuring lactate
    Inigo’s Lab Test Assessment

    Zone 1—I agree with Inigo—it’s mostly for recovery. Zone 2, however, is the real engine builder. It’s not hard, and it’s not moderate. It’s steady, aerobic work. For most of us, this lands around 70–72% of max heart rate. Here is the critical point of clarification: what Inigo defines as Zone 2 training, in the five-zone model I use would be defined as Zone 1. In the Zone system I use, Zone 2 is about 73-82% of maximum heart rate and a training zone that is the culprit for much of the overtraining I have seen. Whether one subscribes to the polarized model of training first proposed by Selier, or a pyramidal approach, the Zone 2 debate has been good as it has brought the proper focus to the majority of our training time and the need to control intensity effectively.

    High-Intensity Zones

    So now that we’ve cleared up Zones 1 and 2, what about the rest?

    Here’s where it gets messy again. Some coaches and physiologists anchor higher zones around anaerobic threshold ( a questionable concept), lactate threshold, ventilatory threshold 2, O2/CO2 crossover points, you name it. But to me, those are arbitrary and probably not real metabolic anchors. They try to pinpoint the same thing: the exponential rise in metabolic cost with increased effort. Fair enough, but it doesn’t make them useful anchors.

    Taking Functional Threshold Power or Critical Power, both define sustainable outputs over time. Great for tracking fitness progress, but the durations they’re tied too often don’t match race demands. And that old “hour-long effort = anaerobic threshold” rule of thumb? Let’s be honest, it’s unvalidated and unreliable.

    I think it’s time we throw most of these out with the morning trash. There’s no solid metabolic validation behind them, and no reason to assume they reflect actual physiological functions. What we do know is that for every athlete, there exists a maximal sustainable pace, power, or intensity over a specific duration. So, let’s use that.

    Zak Ketterson’ undergoing lactate testing during a testing session. (Photo: Zak Ketterson)
    Practical Zone Setting Based on Race Durations

    In the endurance sports I coach, events typically range from three minutes to two hours. So, the logical approach is to assess the intensity athletes can hold across those durations—and then use that to define training zones. Based on Véronique Billat’s research, I use a six-minute max effort as an anchor. It aligns well with the duration needed to hit VO2max. That six-minute effort sets the ceiling for most high-intensity work, especially for athletes racing for longer durations.

    What I’ve found? The difference between that six-minute max and race pace for events lasting 1–2 hours isn’t huge—typically in the 5–7%, maybe up to 10% range.

    I also use maximal sprint tests to determine speed/power reserve. That’s a different conversation, but important. Your ability to improve performance is tied to how much reserve capacity you can develop.

    In Summary

    There’s no need to chase arbitrary lab metrics ; we should simply start focusing on what matters: duration, intensities, and sustainable efforts that align with race performance. Zone 2 or Zone 1 under my model, is your foundation. The higher zones? Anchor them around efforts that reflect the demands of your sport, not some lab threshold with shaky definitions. Again, some will ask whether lab tests are more accurate? NOPE, I have done serial lactate testing over several days, multiple times. The daily variation is as large or larger than how we estimate zones based on these simple heart rate tests.

    Simple. Practical. Effective.