Intensity Distribution and Plan Modifications | 80/20 Endurance

Intensity Distribution and Plan Modifications

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    I’ve listened to Scientific Triathlon podcast over the years. Mikael seems to really resist the idea of a magic intensity distribution number (e.g. 80/20) that is the best for every athlete.

    A few thoughts prompted by both sides of the argument:
    I am convinced of Matt’s position that training volume is the single most effective way to improving race performance, and understand the importance of avoiding the “moderate intensity rut” in the pursuit of a beneficial increase in training volume, so the 80/20 formula is useful with that. And as I go through the 70.3 Level 2 training plan, finished the highest volume week before taper last week and I note that there are several workouts over the last few weeks that have Zone 2 intervals and in the workout description it mentions that these Zone 2 intervals are meant to be at race pace of the upcoming 70.3, and, as it is written, states that could be Zone X for advanced athletes. I realize that the priority for these training weeks is these race pace intervals and the overall training volume, and that the intensity distribution for these weeks will be an “exception to the 80/20 rule.” I have interpreted this guidance to just go ahead with doing the Zone 2 intervals as the Zone X intervals trying out what I might be able to hold for the 70.3 race effort, keeping the other workouts as defined, and NOT adjusting other workouts to get the week to around 80/20. So, for last week my bike power distribution was 74%/26%, my run power and pace distribution was 57%/43% (but my run HR distribution was 71%/29%, not sure if I had a error with my HR strap that led to the HR being so much lower than power/pace)

    So, I see in the final weeks of 70.3 training that because the racing can be in Zone X that Zone X becomes a focus of the training – so while the name for all of this is 80/20, there are important exceptions that are officially sanctioned.

    In addition to that, two thoughts on other potential variations:
    Is finding the right intensity distribution critically dependent on recovery rate? Would it make sense to have age get factored into intensity distribution or volume? We know that generally 25 year old males recover much faster than 50 year old males, right? So if training volume were constant between the 25 year old group and the 50 year old group, I would think the 25 year old group could handle, recovery from, and adapt to, a higher % of moderate and high intensity training time than the 50 year old group, right? If we agree on that, then might the 25 y/os get a higher % than 20% of mod-high, and/or the 50 y/o get a lower % than 20% of the mod-high? In other words, in reality, is the right intensity distribution more athlete specific? If so, what are the metrics one would look for to find that individual optimal intensity distribution? For the aggressive and ambition triathlete, would that be to ramp things up progressively and then look for early signs of overtraining?

    * Matt Dixon’s book Fast Track Triathlete includes the concept of “Key” workouts, and “Supporting” workouts for working triathletes with a busy schedule that may need to cut back the training schedule in a given week here and there to make it work with work schedule, family, etc. The idea is to go into a week knowing what the most important workouts are to accomplish as close to as-written, and what workouts can be scaled down or eliminated as one’s real life schedule interferes with the scheduled training plan. I assume from my 80/20 experience that doing the full week (in an 80/20 plan) as defined is, of course, optimal, but that if a big barrier to completing the full week’s workouts were to appear, that, as a limited solution (ideally just for that one week), I would start to reduce or scrap the Zone 1-2 workouts as needed to be sure the Zones 3-5 workouts are completed successfully, and I would focus on proper recovery (keeping the quality of my nutrition and sleep high) to do the best I could to balance out the higher % mod&high intensity. A couple of questions related to this: 1) do you have an opinion that some workouts in the 80/20 plans are key workouts for successful training adaption, and other workouts are less critical to training adaptation? If so, is there a rule of thumb on this, like Zones 3-5 workouts are key? I did see mentions of trying to keep the step cycle at 80/20 if the week is off. But if I were to have to scrap some low intensity workouts in a week due to work and family, but it wasn’t a physically or mentally exhausting week from work and family, would it make the most sense to then have the next week have a larger share (than 80%) of low intensity workouts to make it all add up to 80/20 for the step cycle or would that be underachieving what I could do in my training as I prepare for a race?

    David Warden


    gonna need a couple of weeks on this one. I count 11 questions. Good stuff, just need to set aside an hour.



    Thanks, Coach David. I look forward to reading your guidance when you are able .

    David Warden

    Ted, thanks for giving me some time on this one. There were actually less questions than I thought.

    When is your race? It’s got to be close now! Looking forward to hear about it.

    First, let’s establish that I have a vested interest in the 80/20 system at this point. What started out for me as a professional best-practice based on empirical evidence is now a commercial enterprise. I’m not going to be the most object individual to comment on this. If new research comes out that shows that 80/20 intensity balance is a terrible way to train, I’m sort of screwed. But, as Matt like to say, “the human body is not a smart phone”. We’re 5,000 years from any major “upgrade” to the most efficient way to train for homo sapiens, and I’m confident that most efficient way to train is 80/20. My comments:

    – Mikael is a great coach, very smart guy. I’ve been a guest on his show. We disagree on a specific ratio of the optimal way to train. If there is not a magical ratio, that implies that an intensity balance of 100/0 or 0/100 are viable methods, and we know that is not the case. I’m sure Mikael would say that he thinks there is not a universal optimal intensity balance, and it’s different for everyone. Maybe, but I would still be confident that we’re talking 77/23 or 82/18…it’s going to be really close to 80/20 for everyone.

    I would also like to see the research refuting an 80/20 balance, and present the following to make the case for 80/20:

    Seiler, K. S., & Kjerland, G. O. (2006). Quantifying training intensity distribution in elite endurance athletes: is there evidence for an “optimal” distribution? Scandinavian Journal of Medicine and Science in Sports, 16(1), 49-56.

    Esteve-Lanao, J., Juan, A. S., Earnest, C. P., Foster, C., & Lucia, A. (2005). How Do Endurance Runners Actually Train? Relationship with Competition Performance. Medicine & Science in Sports & Exercise, 37(3), 496-504.

    Esteve-Lanao, J., Foster, C., Seiler, S., & Lucia, A. (2007). Impact of Training Intensity Distribution on Performance in Endurance Athletes. The Journal of Strength and Conditioning Research, 21(3), 943.

    Seller, S. (2010). What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance, 5(3), 276-291.

    Laursen, P. B. (2010). Training for intense exercise performance: high-intensity or high-volume training? Scandinavian Journal of Medicine & Science in Sports, 20, 1-10.

    I respect skeptics of the 80/20 system, but I invite refuting empirical evidence for review.

    – The principle of specificity is as important as the principle of optimal intensity balance. For some athletes, for some distances, Zone X is the right place to race. It’s not the right place to train most of the time, but it’s the right place to race some of the time. That means Zone X should be included in some athletes training as they approach their race. We write our plans for a “typical” athlete, and don’t know if they will be racing in Zone X or not. Therefore, “your results will vary” during the final weeks of 70.3 and IM training. We write those weeks at 85/15 intensity balance, and assume that the athletes who incorporate Zone X in racing are 70/30 for those weeks, which is right where you ended up (except your run pace, which seems like your Pace zones are too low right now…) Remember, Zone X is not some sort of intensity cliff or third rail. Low Zone X is infinitely better than high Zone X, and the recovery time is significantly different between the two extremes.

    – Is finding the right intensity distribution critically dependent on recovery rate? Somewhat, but not really. You’re suggesting that if Athlete A can recover completely n 24 hours, but Athlete B in 72 hours from the same workout, that Athlete might be able to perform 50/50 training. The advantage of going slow is more than just recovery. Things like glycogen stores, slow-twitch muscles, and metabolic rate (fat burning) can only be maximized with low-intensity training.

    – Would it make sense to have age get factored into intensity distribution or volume? Maybe. The primary research on 80/20 is with elite athletes, not Master’s athletes. However, I’d propose the difference would be in polarization of high intensity, not overall intensity balance. Meaning, an older athlete would benefit from performing Zone 3 at the low end of Zone 3, and an elite at the top end of Zone 3. Same 80/20 ratios, two very different experiences. Here’s the punchline: All athletes, regardless of age or recovery rate need the 80% low intensity for critical aerobic benefits. What you do with the 20% is based on your age, experience, and ability to recover. That’s the beauty of Zone ranges, you can have very different outcomes and flexibility and still be 100% 80/20.

    Do you have an opinion that some workouts in the 80/20 plans are key workouts for successful training adaption, and other workouts are less critical to training adaptation? Oy vey. This is complex. I’d like to answer this one, but there are just too many “it depends.” What plan distance? What is the adherence level to the plan? What point in the plan? What are the athlete’s strengths and weaknesses? What is the athlete’s experience level? Ideally, I would want the athlete to do what I would do if I were their coach: adjust the plan to maintain the 80/20 ratios. If they miss a 2-hour easy ride, I adjust the plan accordingly to reduce high intensity or increase low intensity in the upcoming sessions to keep the balance. I don’t have to do it all in one week, I can spread it out over 3 weeks if I need to. Interesting news on this front: 80/20 Endurance is about to launch a new product with TrainingPeaks that is an AI training plan. If you miss a workout, it automatically adjusts to maintain the 80/20 ratios. See Like the ubiquity of structured workouts we have now that solved problem X, this intensity balance re-calculation issue could be a problem long solved 3 years from now with this new technology.



    Thanks for this thoughtful and thorough reply. All makes sense. Going to let this sink in a bit now.

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