 There are many training theories out there right now, but two of the most popular amongst cyclists are sweet spot training and polarized training. And the two are not very similar. In fact, they're almost opposites of one another. I'm going to be getting into what each method entails, but more importantly, I'm going to be diving into the science to see which method actually produces the best results. Welcome back to another video. If you're into reading and watching cycling training content, then you may have heard of sweet spot and polarized training. And if you're not into cycling training content, then I don't know, you're on the wrong channel. I think everyone watching this is on the wrong channel, honestly. You know that they're only here for my pro tips, right? And you don't give me nearly enough airtime. To start things off, let's get into what sweet spot and polarized training actually look like before we dive into which one is the optimal strategy. And we'll start with sweet spot. People have different definitions of where the sweet spot lies, but generally it's right under your FTP or the power you can sustain for an hour. Usually 85 to 95, 97% of your FTP is what most consider sweet spot. Plans that emphasize sweet spot training of which there are many, have you do a lot of work at this intensity? No surprises there. The theory is that this intensity gives you the most bang for your buck in that you're getting a lot of physiological adaptation for a minimal amount of physiological strain. This could potentially mean that you could do this intensity multiple days in a row or many times throughout the course of a week and see bigger gains as a result. On the opposite end of the spectrum, we have polarized training. And I say opposite because instead of trying to spend a lot of time in that sweet spot zone, you actually try to avoid it altogether. That's right. Polarized training involves either riding easy or hard with very little time in the middle because you can't spend that much time riding at super high intensities. Inevitably you end up spending a lot of time riding easy and some time riding hard. You may have heard polarized training referred to as 80-20 training because 80% of the time you're training easy and 20% of the time you're training hard, although this ratio is not set in stone. There are many zone models out there. Some have five zones. Some have as many as seven zones, but polarized training uses the simplest zone model of them all with just three zones. Nah, dude, that ain't the simplest. The simplest is my zone model and it's just got one zone. The hard enough to drop you zone. I call it the Broan model. You've likely heard of lactate threshold and in cycling people use this interchangeably with FTP, but there's actually a second lactate threshold that lies at a lower intensity at about 75 to 80% of your FTP depending on the person. This is where blood lactate levels first start to rise. The reason more emphasis is placed on the second lactate threshold is because once you cross that point blood lactate levels spike and it's also at this point where you start to fatigue fairly quickly. These two thresholds are what separates the three zones in polarized training and those that follow strict polarized spend a lot of time in zone one below that first threshold sometime in zone three above the second threshold and almost no time in zone two between the two thresholds. Again, sweet spot training is in zone two between the two thresholds. So these two methods are taking very different approaches throughout this video. I'm going to be referring to zone one, two and three and know that I'm using a three zone model where sweet spot is more or less zone two. All right, with that out of the way, let's get into the good stuff. Which one of these methods actually has the science to back it up? This study using different training models in train cyclists had subjects complete a six week training plan using either a polarized model or the threshold model. It's important to note here that in this study and many studies like it when they're referring to threshold training, they're not referring to training at FTP like cyclists generally tend to think. They're referring to training between the two thresholds or what we might consider sweet spot or zone two. Subjects in the polarized group spent 80% of the time at zone one zero time at zone two and 20% of the time at zone three. The threshold group spent 57% of the time at zone one 43% of the time at zone two and no time at zone three. The result, it was polarized training that came out the winner in terms of improvement to peak power output, lactate threshold, high intensity exercise capacity, and 40k TT time. So the cyclist that did polarized training saw greater improvements in this study. But one thing I don't like about this study is that the group that did sweet spot training did no training above FTP. And even the most die hard sweet spot fans do high intensity intervals. There are studies, however, that have a more normal distribution across all three zones in the sweet spot group. This study on runners, for instance, again split subjects into a polarized group and a sweet spot group. The polarized group did 77% of their training at zone one, 3% at zone two and 20% at zone three, while the sweet spot group did 46% at zone one, 35% at zone two and 19% at zone three. The sweet spot group here has a more well rounded distribution across the three zones. And the polarized group is still almost spot on with that 80-20 ratio of zone one to three. So what did they find? The polarized group improved their 10k time by 5%, while the sweet spot group improved their time by just 3.6%. And while this in itself wasn't statistically significant, a subset of runners that stuck the most to the polarized training method showed the greatest improvement. And the study concludes that polarized training can simulate greater effects than between threshold training. Very interesting results here, especially considering that the two groups did almost the same amount of time at zone three, 19 versus 20%. So we're more or less cutting that out as a confounding factor. It seems that adding more time at zone two to the training plan not only didn't help, but actually hurt the runner's performance. This is something that I've been preaching on this channel for a while now. Most people are doing their easy endurance days too hard and it's not helping them. Oh, sorry, I wasn't paying attention to the last part. You said go so hard that you make yourself bleed out of your eyes every single time you get on the bike. Cool, yeah, I'll just keep doing that then. And these two studies are not the only research we have coming to this conclusion. This review looking at many studies on the current scientific evidence for polarized training found that the effect size for change in endurance performance was 0.85 to 2.8. This was greater than the effect size for the more traditional threshold training method, which ranged from negative 0.42 to 2.16. So it is possible to see a big improvement with sweet spot training, although on average, the improvement was greater with polarized training. And let's not forget that that range ran into the negatives with sweet spot training, meaning that some subjects actually decreased their performance using that method. This very likely may be due to overtraining and is something that I see a lot in athletes coming from sweet spot heavy plans. They may be able to handle sweet spot multiple times a week at first, but over time it drains on you and you become flat. This may have something to do with how going over that first threshold or going up into zone two impacts our nervous system. This study on autonomic recovery after exercise found that exercise below the first ventilatory threshold causes minimal disturbance in ANS balance. Further, the first ventilatory threshold may demarcate a binary threshold for ANS slash HRV recovery in highly trained athletes, because further delays in HRV recovery with even higher training intensities was not observed. If you're going up into zone two, you're likely causing stress on your autonomic nervous system. This is okay if you do it a couple times a week, but do it day after day for months and you have a problem. This may be the reason that replacing that zone one time with more sweet spot work doesn't seem to help. Going back to that earlier review, they conclude that optimizing endurance training may be best accomplished by using a polarized training program where the individual enjoys zone one, avoids zone two, and gets after it in zone three. Hmm, gets after it. Very scientific lingo there. They seem to be right though, or at least in line with what the literature has to say. This meta-analysis of randomized controlled trials on polarized versus threshold training ultimately came to the conclusion that polarized may lead to a greater improvement in endurance sports performance than threshold training or sweet spot training. That's where the current balance of evidence lies, but there is one potential issue with a lot of these studies, and that's that they do relatively short tests on these subjects. And when the tests are short, then most of the test is done at zone three, so it's not crazy to think that a training program that emphasizes zone three would produce better results in those tests. However, cycling events are often longer than an hour, and inevitably you'll be spending a lot of the race at zone two. So then wouldn't avoiding zone two in your training hurt your performance? This study on the training intensity distribution of Ironman triathletes had subjects complete the same training program before they all completed the same Ironman event. Ironman distance triathlons are primarily done in zone two between the two thresholds. Despite this, most of the training was done in zone one. Interestingly enough though, they found that a higher percentage of time training at zone two was associated with slower competition times. The study concludes that while athletes perform with heart rates mainly in zone two, better performances are associated with more training time spent in zone one. A high amount of cycling training in zone two may contribute to poorer overall performance. That's right, more time in the sweet spot zone correlated with worse overall performance, and this is an Ironman triathletes who spend a lot of time in that zone during a race. However, there is a similar study to this done on half Ironman triathletes that comes to a slightly different conclusion. The study in question splits subjects into a polarized and pyramidal group. The pyramidal method is not something that we've talked about yet, but in this study that group did roughly 78% of training in zone one, 19% in zone two, and 3% in zone three, as opposed to 84, 5, and 11% in the polarized group. So with pyramidal training, you're still spending a significant amount of time at zone one. But the difference is what you end up doing with that remaining 20%. And with pyramidal, most of that is spent in zone two, as opposed to zone three. And for a half Ironman triathlete, this would be more specific to their race, since most of their race is done at zone two. Will this end up producing better results though? They found no significant differences between the polarized and pyramidal group in competition times. In fact, only two seconds differentiated both groups in the race that lasted over five hours. The study concludes that coaches should not rule out the training prescription in zone two, since training time in this zone positively correlated with performance in the half Ironman competition. Given what we've read up until this point, this study may seem like an outlier. However, this isn't the only study testing the pyramidal and polarized method that came to this conclusion. This study on national elite rowers put subjects into a polarized and pyramidal group and found that changes were not statistically significant between the two groups. Polarized did not prove superior to pyramidal, possibly due to the similar and very high percentage of time at zone one. It really seems like that may be the key here. Pyramidal training still has you do a lot of time at zone one, and that may make the difference. And sure enough, this review article on training intensity distribution among elite endurance athletes finds that most retrospective studies on elite athletes reports a pyramidal distribution despite a large body of evidence in support of polarized training, at least over more traditional training. This review concludes the same thing. Polarized and pyramidal are the most effective strategies. So polarized first pyramidal is one better than the other. At this time, it doesn't seem like we have enough data on pyramidal and that review that I just referenced stated this saying that more research needs to be done. Given the current evidence we have, though, I think it's safe to say that a large portion of your training needs to be done at zone one. If you're crushing sweet spot or tempo day after day, or every time you get on the bike, then this is a mistake. And not only is it not helping you, but it may actually be hindering your progress to high intensity days a week, or occasionally three should be all you need. And if the event that you're training for requires a lot of time at sweet spot, then it may make sense to include some sweet spot in your training plan, especially considering the evidence we have on the pyramidal approach. Just don't make it the bulk of your training like so many sweet spot training plans tend to do. The bulk of your training should be zone one easy endurance miles. I really wish YouTube let you leave more than one dislike per video. Thanks for watching. If you enjoyed this video, be sure to give it a like, subscribe for weekly science based cycling videos just like this one, and share this video with your cycling friends. I'll see you in the next one.