What is it: “Polarized Training” in the simplest possible terms is doing (pretty much) only easy rides or hard rides. If you are familiar with the model of five training zones (Z1 = recovery, Z2 = aerobic, Z3 = sweet spot, Z4 = threshold, Z5 = anaerobic), then this means doing essentially all workouts in Z1/Z2 and (high Z4)/Z5. Now, especially if one is measuring using heart rate to measure effort, then clearly to get to Z5 you have to pass through zones 1-4, so clearly you can never fully avoid those intermediate zones. However the goal should be to never linger in the intermediate zones.
If you’ve read much about training you may have heard the idea that amateurs (as compared to pros) tend to do their easy rides too hard, and their hard rides too easy. This is another way of saying that amateurs tend to train near threshold (Z3 / low Z4), while pros tend to train in a polarized manner. Note that in the research literature it is more common to group heart rate into only three zones, with (Z1 + Z2) = new Z1, (Z3 + low Z4) = new Z2, and (high Z4 + Z5) = Z3. For consistency with the literature, I will use this three zone model.
The appeal: So why should you care about polarized training? Simply put, polarized training is appealing because it has scientific backing, and because it has a degree of “just makes sense.” Let me expand on that second remark a bit.
You may very well have heard about studies showing that doing only intervals yields the same benefit as “base training” type riding. This sounds wonderful at first, especially for those of us who don’t have the time/weather to ride for 4-6 hours a day during the winter. The problem with this is that once you start doing intervals, you quickly realize that they are extremely hard on your body. Most training plans recommend only doing intervals 2 times a week, since recovery takes so much longer. In addition, intervals are not really what most people consider “fun.” Sure, it’s nice to push yourself hard, but it’s also quite dull to “live by the timer” and not be able to just ride freely. Thus doing intervals alone is not really feasible for the majority of people.
Polarized training on the other hand tends to shoot for 80%/0%/20% (Z1 / Z2 / Z3, resp.). Let’s say you are training for 10 hours a week. Then you would spend approximately 8 hours in Z1 (aerobic) and 2 hours in Z3 (anaerobic, or “very hard”). Considering that a single Z3 interval is usually relatively short (30 sec – 20 min), two hours in Z3 is still a decent chunk of time. Thus polarized training includes the benefits of high intensity interval training, but allows athletes to avoid overtraining by letting them spend a large chunk of time doing low-intensity work.
The science: Whenever one reads about training methods it’s best to avoid relying on “common sense.” The reason is that human physiology is incredibly complex, and if training was as simple as applying common sense to the problem, then all of training theory would have been solved by now. Instead there are tens of thousands of PhDs throughout the world studying training methods. They would not have jobs if all it took was some “common sense.”
So what does the science say about polarized training? It’s not hard to find studies about the efficacy of polarized training on elite athletes (I recommend this video). This is all well and fine, but if you are reading this blog you are probably not an elite athlete. A common criticism of traditional base training is that (according to some) it’s only effective if you train many hours a week, perhaps 25+ like elite athletes do. However, elite athletes are fundamentally different from you and I. Not only do they train more, but they have drastically different genetics and physiology, and they have tens of thousands of hours of training already under their belt. Thus you should be wary of the applicability of any study that focuses on elite athletes.
However, there are two smaller studies that focused on polarized vs traditional (Z2-heavy) training for recreational athletes. These people have trained 5-10 hours a week for several years, but are not elite athletes. The question is then, if you take the polarized training model developed for athletes training 25+ hours a week, and scale it down to 5-10 hours a week, is it still beneficial? These studies say “yes” (with some caveats). In the following posts I will discuss those studies, and how we can use them in our own training.
Initial summary: I haven’t yet covered what the studies say, and how they actually use polarized training. In order to avoid one gigantic post, I will be splitting this introduction into several posts. In parts 2 and 3 I will cover two studies. In part 4 I will discuss actual implementation of polarized training to a new racers training routine. Hope to see you there!