 Doing two workouts per day is pretty common amongst high level athletes of almost all endurance sports, including running, swimming, cross country skiing, and so on. But not for cycling. There are exceptions of course, but generally even pro cyclists with all the time in the world to train don't do two rides in one day. If they plan on riding more that day, then they'll simply do one longer ride as opposed to riding twice. Why is this? Well for starters, our bodies are better able to handle long periods on the bike than they are, say, long periods of running, both from a recovery and injury standpoint. On top of this, bike races are generally longer in duration than your average event in other endurance sports. For example, your average pro road race can last four to six hours or more, which is two to three times longer than it takes an elite marathon runner to run a marathon in around two to two and a half hours. And a marathon is considered a long event in running. Again, a five hour road race is not considered long, that's just standard. What is this dude talking about? I've never seen an option for a five hour race on Zwift before. Given this, it makes sense that cyclists would naturally gravitate towards doing one long ride and then calling it a day. But is there something that cyclists are missing here? Is there some sort of physiological benefit to doing two workouts in a day? And if you're forced to ride twice in a day, maybe because you commute to work or because you spend so much time training indoors that splitting up the rides is beneficial for your motivation, then is doing this helping you or hurting you? This is what I'm going to be addressing today by taking a look at what the science has to say on this topic. Now it's important to note that the research here is pretty limited, but there are still some interesting findings that can give us some insight into the pros and cons of doing two workouts per day. Also, at the end of the video, I'll be discussing how to fit weight training into your schedule, because if you're a serious cyclist, then you should be weight training and that usually means that you're going to be doing two workouts per day, your lift and then your ride. And the order in which you do them and the amount of recovery time you give yourself between these two workouts matters. All right, without further ado, let's jump into the science. This study put two a day training to the test by having subjects follow one of two training patterns. In the first, subjects alternated between a 100 minute steady state aerobic ride one day and an eight by five minute interval session the next. The other group did both sessions on the same day every other day so that the volume was the same and both groups trained like this for three weeks. I've got to say I'm not too impressed with how they structured the training in this study and that will continue to be a theme in the two a day research for whatever reason. First of all, if somebody's going to train twice per day, they're not going to only train every other day. A much better solution would have been to have both groups do the same volume, but one group only does one ride per day and the other group splits the volume into two rides per day. Also, the two a day group does the steady endurance ride before the interval session. Again, not the way I would have structured it because this will negatively affect the quality of that interval session. But it appears that they did this to see what the effect of doing these sessions with low muscle glycogen would be. And sure enough, glycogen levels were significantly lower in the two a day group, which as you might expect resulted in the subjects training at a lower relative intensity. Although by the last week of the training, this group seemed to be catching up a number of physiological responses happened in this two a day group, including an increase in resting muscle glycogen concentration and whole body fat oxidation while riding. But performance in a one hour time trial was similar between the two groups. While the performance was not different between these groups, the physiological changes highlight some potential benefits of doing two a day training. And these benefits have considerable overlap with doing fasted training in which someone trains in a fasted state, usually by skipping breakfast before they go ride. That being said, now would be a good time to point out that the research on fasted training is mixed. It appears that fasted training shows beneficial effects in terms of signaling and transcription. But to date, few studies have been able to show any effect on performance. And given how important carbohydrates are to performance, this isn't surprising. That being said, there are certain fasted training strategies that do show promising results. For example, train high sleep low in which athletes train with high glycogen late in the day and then don't completely refuel afterwards so that they can go to bed in a low glycogen state and train in a low glycogen state the next morning. If this method sounds like pure torture to you, then I'm right there with you. Well, yeah, if these people were denied access to hypergain, beast mode, mask gain, or raw addition before they ride that morning, then technically, that is considered torture in 23 different countries. I wouldn't generally prescribe this to somebody, but it does appear to improve performance in a number of studies. And judging by the adaptations made in the last study that I referenced, the effects seem to be similar with two a day training. This study on twice a day versus once a day training was set up very similar to the first with three weeks of training in which subjects did a hundred minutes of endurance training followed by a high intensity interval session, either two or 14 hours later, essentially making it a two a day or once a day pattern. The study looked at a wide range of fitness markers and the only two that showed any difference between the two conditions was mitochondrial efficiency and perceived effort, which both improved more when subjects did two workouts per day. I wouldn't call this strong evidence that two a day training is better, but it is something. And there are other studies like it that test this once a day versus twice every other day approach. And some of them do look promising. However, from this review looking at many studies on the topic, despite increasing the muscle adaptive response and reducing the reliance on carbohydrate utilization during exercise, there is no clear evidence that these strategies enhance exercise performance. Low glycogen training is a reoccurring theme that you see with two a day training. And while it appears that there are some physiological benefits, the evidence that this actually translates into an increase in performance is pretty weak. But is this low glycogen state even the reason for these adaptations in the first place? As the intro to this twice a day study puts it, it's unknown whether this greater signaling response is due to performing two exercise sessions in close proximity as a first exercise session is necessary to reduce the muscle glycogen stores. Basically, these studies have subjects do a glycogen depleting workout in order to train in a low glycogen state shortly thereafter. But this is a potential confounding factor. What if the simple act of doing two workouts in close proximity to one another is the reason for these adaptations? The study tested this by having subjects do the second session two hours or 15 hours later, so effectively a two a day or once per day approach much like the previous study. But the difference was that the second trial in both conditions would be in a low glycogen state. By doing this, they could rule out whether it was the low glycogen that was causing the adaptations or the close proximity of the workouts. What they found was greater physiological adaptation with the two per day approach. This led them to conclude that the greater signaling with the so-called train low approach can partially be attributed to doing two exercise sessions in close succession rather than exercising with a reduced muscle glycogen. So it appears that the benefits of two a day training may have something to do with the fact that you're doing two rides very quickly one after the other. Is this a point in favor of two a day training? I don't think so and here's why. If we take this quick workout succession idea to its logical conclusion, there is no quicker succession of two workouts than just combining the two and doing one longer ride. Then you effectively have zero time between the two workouts. Also, even if training with low glycogen is the main driver behind these physiological adaptations that we're seeing in these two a day studies, then we can still achieve this by doing one longer ride per day because the longer you ride, the lower your glycogen stores will be and either way we're training in a low glycogen state. Again, it would be great to see a study in which one group does one long ride per day and then the other group does two shorter rides per day. Make the total volume the same between the two groups and see which group gains the most fitness by the end of the study. Unfortunately, we don't have that right now and given the research that we do have, I would say that the evidence that riding twice per day has some sort of extra benefit is pretty weak. Of course, all of this assumes that you have the time to do one long ride regularly in your training. And for many people, this simply isn't an option. And for these people, riding twice per day can be a good solution. Let's not forget that training volume is important for making improvement. Optimal training requires combining lower intensity longer duration sessions with fewer higher intensity bouts. If you don't have time to do a long ride multiple times per week or you're stuck indoors and the thought of doing five hours on the trainer is quickly squashing your motivation, then oftentimes your best option is splitting that workout into two during training periods where volume is prioritized. If you can get to your weekly volume goal by doing two days, then this is better than having to compromise on your weekly volume and sticking to one ride per day. Ideally, though, you would still have one day per week where you go out for that one long ride. Also, if you are going to ride twice in a day and you have any sort of intensity plan that day, then I would do the intensity during the first ride. As we saw from the research I referenced, that first ride will reduce your muscle glycogen stores and this will reduce the quality of that second ride that day. I actually wouldn't be surprised to see more improvement from the two-day group if they had flipped the order of the workout so that they were performing the interval session first. Doing two rides in one day is not the only time that two-day workouts comes up in training, particularly when you throw weightlifting into the mix. If you're a serious cyclist, then you should be lifting if you want to improve your performance and at a certain point you will have to lift and ride in the same day. So what is the best approach here which should be done first and does the amount of time between these two sessions matter? This meta-analysis looking at the effect of concurrent strength training and endurance training sequence found that lower body strength was significantly higher when strength training was done before endurance training. This compromise in strength training may last six to eight hours after endurance training, but for maximal aerobic capacity the exercise sequence has no impact on the ensuing adaptations and this preferred order has been confirmed in many studies. What does this mean in terms of how you should time your gym sessions? Well it all depends on what part of your season you're in. In the off season and even early on in the base season when you're prioritizing your gym sessions, it makes the most sense to do the gym session first and preferably after a rest day so that you can be as fresh as possible for that gym workout. This changes as the season approaches though. Remember that our goal is to become faster cyclists not necessarily to gain as much muscular strength as possible and if that is your goal then perhaps this is the wrong channel for you. As your peak approach is you want your high-intensity sessions to take priority over every other workout that you have on your calendar including your gym workouts. If you have intervals and a gym session scheduled on the same day then do the intervals first. If it's just an endurance day then the order is less important but you probably will get a little bit more out of that gym session if you do it first. Although at this point in the year you'll probably just be doing maintenance lifting and being as fresh as possible for that gym session is less important. Finally it's a good idea to separate the two workouts by a couple hours so you feel better for that second workout. If I'm doing a gym session and a ride in the same day and the day is relatively free and I can schedule these workouts whenever I want then I'll usually do the first workout shortly after I wake up in the morning and the second workout later in the evening usually right before dinner. Huh well if there's one thing I got out of this video is that this dude has way too much time on his hands. All right back to scrolling through cycling meme pages on Instagram. Thanks for watching if you enjoyed this video be sure to give it a like subscribe for more science-based cycling content just like this and share this video through cycling friends. I'll see you in the next one.