To HIIT or to LSD.... that is the question!

Now, if the title of this article has your head spinning through your English vocabulary trying to figure out what the damn acronyms could possibly mean, rest assured - I'll answer that!

Image by Rachael McIntosh (Canadian Heptathlete)-

So, if you've only clicked on the link to this site to find out the answer to what those damn acronyms mean, you have come to the right place:

HIIT: High intensity interval training; made popular as of late by celebrities such as Kayla Itsines (search my site for my previous post about Kayla if you're in the mood for a good rant - but not before you find out the second acronym below...). Tabata training is also often lumped into this category due to their similarities, involving intermittent periods of high intensity and rest intervals (Tabata specifically being 20 second work to 10 second rest ratios).


LSD: Long slow distance Training; a term you'll often hear runners talk about, more often than not, when you ask them how their weekend went. You: "What did you get up to this weekend"; Them: "Just did an LSD on Sunday. You?" If this conversation has never happened to you, it is likely that you don't have many friends that enjoy spending all their free time training and buying mountains of food, rather than doing other productive things. This opinion comes from myself, an endurance athlete.... funny enough.

So you either clicked on the link to this blog article because you were interested to know what the acronyms stood for (which have now all exited my site), or because you already knew what the acronyms stood for, and genuinely wanted to know a little more about training (you!). Bravo if you are the latter because my sole purpose of this article is to try to distinguish one of the most confusing questions in training in a dummy-proof explanation.

In endurance training, the intensity and volume of which to train are among the questions the most heavily debated in the literature, as well as in the "blogger-sphere". Many a coach, famous or not, has written books and articles about the best ways to train for endurance events, and these two questions are likely the most important. For this article, let's focus on the intensity, and try to distinguish which type of training is better, hard intervals (ie. running stairs, sprints, tabata circuits that make you realllllly sweat), or long slow distance training (ie. comfy endurance efforts, that are enjoyable... YES enjoyable!, conversational, and much less fatiguing).

Image by Rachael McIntosh (Canadian Heptathlete)-

Currently in the world of research, there are two different patterns of training intensity distribution: 1) The threshold-training model

This model emerges from numerous studies showing improvements in participants' fitness (measured various ways.... VO2max, time to exhaustion, etc) improving over the course of the study due to higher intensity or training at or around lactate threshold.

2) The polarized-training model

This model, a newer training model, and often called the 80/20 method, emerges from a number of more recent studies, observing that elite level endurance athletes (namely, rowers, time-trial cyclists, and elite marathoners), generally spend the majority of their training below the lactate threshold.

Image by Rachael McIntosh (Canadian Heptathlete)-

By now, I'm feeling that more definitions are due, because if you do not know what the lactate threshold is, you might be becoming more lost. Think of when you go for a run. OK, maybe you don't run.... but I'm pretty sure most of us were forced to do a little running in school at some point! So.. picture yourself running. At the beginning, you're running slowly to warm up, could probably hold a full conversation with a friend, and aren't sweating very much or at all. As you continue, you start to feel pretty good, you pick up the pace, and you notice your breathing increases, making it a bit harder to hold a conversation, but not impossible, and causing you to sweat. With over half your run being done, you decide to really pick up your pace for the last few kilometres back to your house, because you can remember all the yummy snacks waiting for you in the fridge. Your breathing REALLY increases now, there's no way you could hold a conversation, you're sweating, and your muscles are starting to burn. The point at which you went from being able to hold a conversation to no longer having that ability, is likely somewhere around your lactate threshold. Past that threshold, breathing increases, the body cannot buffer the lactate produced by your muscles from the higher intensity of exercise, and this intensity won't be maintained for too long.... likely, in your case, just long enough to run quickly back home and crush some post-run "earned" snacks. It seems logical that training "hard" will make you better, right? Well, as most of my articles should be teaching you if you've read them.. is that, it depends.

Endurance athletes, or their coaches specifically, commonly prescribe training zones to lump specific training goals into target days. I like to prescribe training zones to my athletes, especially after a lactate threshold test, because I am giving them specific work in specific zones, based on their physiology.

From a great paper by Siler & Kjerland in 2006, training zones prescribed often divide training into areas below the first threshold (first dotted line above), between the two thresholds; aerobic and anaerobic (middle space between two dotted lines above), and training at high intensities past the lactate threshold (past second dotted line above).

As you can see, there is a stark contrast between both training models, where the ​Lactate Threshold Training model prescribes the most of it's training between the thresholds, whereas the ​Polarized Training model recommends the majority of training below the first threshold, barely any between the thresholds, and a tad bit above anaerobic threshold as well. Maybe you're starting to get the idea of where the 80/20 model of endurance training came from? While the study I'm referencing above was not an experimental study, it was a great study done on male cross-country skiers, a sport that tends to elicit some of the top trained athletes in the endurance field no doubt. Not to mention, the males in the study were high level athletes (see Methods), and the study was simply recreating the notion that other researchers had done, which was observe the polarized model in international class athletes, as mentioned before (Steinacker 1993, Sneinacker et al 1998, Schumacker & Mueller 2002, Billat et al, 2001).

The 80/20 or Polarized Model is likely something none of your friends have heard about, unless they happened to be high level athletes, or have trained with high level coaches. What this means for you, is that if you're an endurance athlete looking to improve your endurance - this model might be your answer.

Does this type of training make sense from a physiological standpoint? Hell ya.

Some of the factors we are looking to improve as an endurance athletes are most modifiable at low intensities. Think: blood volume, plasma volume, mitochondrial content, and economy. All of those sweet sweet adaptations are actually easier to get than you think! Coming back to one of my first points in the article, however, the volume of the training in this "LSD" zone, is a whole 'nother topic.

Training in the high intensity zone (think: Oranj Theory, Spin Classes, HIIT gyms... who base their marketing off the get fit quick models, and who attract mainly the weekend warriors who want to "just sweat"), can also be beneficial. It can help with acid-base balance in the body, can improve ventilation and perfusion of oxygen at the lungs, along with oxygen uptake (think: VO2 max can improve quickly), but it is also super stressful on the body - as you know if you've gone to any of the type of classes or gyms listed above. This stress, over time, can lead to poor sleep quality, increased stress (who needs more of this?) on many systems in the body, decreased recovery time, increased soreness, and potentially a depressed immune system. If you're someone who loves their intense workouts, but who always gets sick... maybe it's time to reevaluate?

"But I'm not an endurance athlete, I'm just a general client wanting to get fit and lose body weight!" Well, this article was not for you, but many in the future will be targeting these topics! Ask me for more information if I've left you hanging.

Obviously, there is no "BETTER" training method between LSD training and HIIT training. They both provoke different adaptations, and are often both used in the development of a good athlete. The fact that many studies have now shown that long slow distance training is over 75% of the training that elite endurance athletes use, potentially because they are able to complete so much volume at such low intensities, should not be taken as coincidence. Science tells us the reasons why these adaptations at low intensities are important, and although the research makes sense, putting research into practice is always the hard part.

Lastly, as seen on my home page:

I'm not kidding! Long runs/bikes/swims rock... let me help you to integrate them into your training.

Yours in health,

References: Billat VL, Demarle A, Slawinski J, Paiva M, Koralsztein JP. Physical and training characteristics of top-class marathon runners. Med Sci Sports Exerc 2001: 33: 2089–2097.

Midgley, A. W., McNaughton, L. R., & Jones, A. M. (2007). Training to enhance the physiological determinants of long-distance running performance: can valid recommendations be given to runners and coaches based on current scientific knowledge? Sports Medicine (Auckland, N.Z.), 37(10), 857–880.

Seiler, K. S., & Kjerland, G. Ø. (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.

Schumacker YO, Mueller P. The 4000-m team pursuit cycling world record: theoretical and practical aspects. Med Sci Sports Exerc 2002: 34: 1029–1036.

Steinacker JM. Physiological aspects of training in rowing. Int J Sports Med 1993: 14(Suppl. 1): S3-10.

Steinacker JM, Lormes W, Lehmann M, Altenburg D. Training of rowers before world championships. Med Sci Sports Exerc 1998: 30: 1158–1163.

#Lactate #Aerobicclass #Aerobic #Anaerobic #HIIT #LSD #Running #Performance #athletes #Athleticdevelopment #Athletics #Threshold

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