Dr. Stephen Seiler, research physiologist and world expert on polarized training, explaining the distribution of intensities at which the best endurance athletes train in his TEDx talk.
Training has been an important topic on this blog from it's beginning. At first I blogged about the books I had read about training. Later, I switched to scientific papers which, in most cases, I found from links on social media which lead to print media which lead to a scientific publication. Recently, one of these social media links led me somewhere else: to a podcast. This podcast featured an interview of one of the foremost academic experts on polarized training, Dr. Stephen Seiler. I have long enjoyed political podcasts, but this was the first podcast I had listened to on the topic of exercise science and I found it extremely enlightening. I was very impressed with Dr. Seiler and, because I am a fellow scientist, I recognized in him a kindred spirit. I may, at some point, review his work critically in but in this post I am going to describe the way getting training ideas from Twitter, podcasts, scientific lectures, and TED talks differs from both training books on the one hand and scientific papers on the other.
On the web page containing the podcast interview with Dr. Seiler were links to Dr. Seiler's Twitter and ResearchGate* accounts which I followed. I downloaded some of his papers from ResearchGate and started following him on Twitter. His tweets are useful in and of themselves, but also useful are the links to other videos contained therein. To date, I have listened to some more podcasts, a TEDx talk (shown in the picture at the top of this post) and a professional lecture. Despite being very different platforms, these videos^ were similar in terms of the kind of information I got from them and I will talk about them as a group, lumping them all together rather than attributing ideas to individual ones.
How does getting training ideas from videos compare to getting them from training books by (non-scientist) coaches or from scientific publications? The biggest issue with getting ideas from books is one that Dr. Seiler touched on in one of his podcast interviews, the issue of trust. What reason do I have to I think the ideas in any particular book are correct? Seiler acknowledges that trust between an athlete and coach is a delicate thing that has to be earned. This reflects not only that athletes need to learn to trust their coach, but also that some coaches should not be trusted, so the athlete is right to be cautious. On the other hand, books usually contain comprehensive discussions of an overall training strategies targeted at specific, well-defined goals, for example, training for your first 100 mile long ride. If you trust a training book, you are set, you know exactly how to train. Scientific papers, at their best, require substantially less trust because the entire purpose of the scientific method is to allow proof to replace trust, not by providing absolute certainty, science does not do that, but providing the data needed to evaluate the strength of evidence supporting its conclusions. Unfortunately, to provide such transparency usually requires investigating very narrowly defined questions which lack the comprehensiveness and context which are the strong suit of training books. You may be convinced by the conclusions of a scientific study but have no idea what it suggests for your training plans. I am finding Dr. Seiler's talks so useful because they occupy an in-between place in the dichotomy between coaching books and scientific papers, providing more context than the papers and more transparency of evidence than the books.
What have I learned from Dr. Seiler's talks?
- Dr. Seiler uses two kinds of data to study which training plans work "best." (The definition of "best" will vary, depending on the individual athlete's goals, of course.) First, he does experiments in the lab where he measures the effect of different training plans (e.g. 4 minute vs. 8 minute vs. 16 minute intervals) on different parameters associated with athletic performance (e.g. functional threshold power.) Second, he studies the training plans used by successful coaches and athletes. The argument here is that this is an evolutionary approach to determining the best training plans in the real world. Those coaches and athletes who use less good training plans have less good results and are removed from his study group by natural selection. It is this second kind of data that was the basis for the graph shown in the photo at the top of this post.
- For a lot of his work, he uses a three zone intensity scale rather than the more common five to seven zone systems`. He defines his three zones based on the rate at which blood lactate increases with increased exercise intensity. There are two inflection points where the rate of increase goes up, and that defines the Zone 1 to Zone 2 boundary and the Zone 2 to Zone 3 boundary. In more than one interview he was asked to translate those boundaries into metrics more commonly available to average cyclists, heart rate for example. Personally, I found those translations problematic, different translations he gives seem to me to give different boundaries. He is also asked to translate his three zones into the more typical five zone, heart rate-based system. He responds that Zone 1 in his three zone system corresponds to Zones 1 and 2 in a five zone system, that Zone 2 corresponds to Zone 3, and that his Zone 3 corresponds to Zones 4 and 5 in the five zone system. However, when he describes the boundaries specifically, it seems to me that his Zone 3 actually corresponds to Zone 5 rather than 4 and 5. The boundary between his Zone 1 and Zone 2 seems less problematic, though it might be in the middle of Zone 2 in a five zone system rather than at the top.
- A naive framing of Polarized Training could be made that all training should be in Zones 1 and 3 (in the three zone system) and little or none in Zone 2. As I listened to Dr. Seiler talk, it is clear that he is much more concerned about not substituting Zone 2 for Zone 1 and keeping Zone 1 training at 80% to 90% of total training than he is about the distribution of training between Zones 2 and 3. This is based on his studies of real world coaching. He does see examples of successful athletes who train in Zone 2, but not of those to substitute higher intensities for Zone 1; all successful athletes that he has studied spend 80% to 90% of their time exercising in Zone 1.
- As a retired academic, I can attest to the fact that paradigm definition is often more important for academic success than for scientific progress. Thus, the cynic might argue that Dr. Seiler's coining of the term "Polarized Training" really comes down to repackaging and renaming things that coaches have been saying for decades. Again, this post is not a critical examination of Dr. Seiler's published works. Nonetheless, I will say is that in his podcasts, he is suitably modest and balanced in presenting his ideas so in this context I think that criticism would carry less weight.
- A relief to me is that Dr. Seiler is much more relaxed about how important the differences between training plans are than some of the more rigid writing on the topic suggest. For an older, casual athlete like me, he might almost suggest doing whatever I want, only making sure to exercise consistently and not overdoing it. His research is focused on getting world class athletes to their very peak of performance where small differences become critical, so his focus on these small differences makes sense in the context in which he works. As one example of this, he noted that doing only long, slow rides will increase VO2max, normally considered one of the main targets of high intensity training.
- A bike ride is characterized by volume (how many minutes you ride) and intensity (how "fast" or hard you ride.) A simplification that most people make, me included, is that doubling the volume (minutes) doubles the fatigue. In one video, Seiler was discussing the well known phenomenon of decoupling, that on a long ride at a fixed intensity, heart rate will stay constant for a while and then start to increase even though speed, power, etc. remains constant. Imagine a three hour ride where heart rate starts to rise at the end of hour 2. Seiler speculated that might mean that the fatigue generated during hour 3 might be greater than during hours 1 and 2.
* ResearchGate is a social media platform for scientists. It is a bit like LinkedIn except it is much more focused on user-provided data. For example, it is a place where a scientist can put their research publications for others to read.
^ Some Videos featuring Dr. Stephen Seiler:
- Flo Cycling Podcast (Sept. 30 2018. Scroll down to episode 13. Flo cycling sells bicycle wheels for racing.)
- Scientific Triathlon: Polarised training with Stephen Seiler, PhD | EP#177, April 15, 2019 by Mikael Eriksson
- Stephen Seiler·TEDx Arendal: How "normal people" can train like the world's best endurance athletes
- Fast Talk podcast, ep. 75: High intensity training with Dr. Stephen Seiler
- How to Create Multi-Year Development Plans, with Dr. Stephen Seiler and Sondre Skarli
- CoachCast by TrainingPeaks: Episode 9: Stephen Seiler
- Load, Stress, Strain: Understanding the difference can make you fitter and faster!
` On this blog I originally used a seven zone system (1, 2, 3, 4, 5a, 5b, 5c) but have recently switched to a six zone system (1, 2, 3, 4, 5, 6). In both cases, Zones 1-4 correspond to those in the standard five zone system, and the remaining zones are all subdivisions of Zone 5.
