Evidence Strong
Why Olympic weightlifters have different muscles: insights from muscle fiber expert Nathan Serrano
If we classify the fiber as, let's say, piñor to A, will it be all the way to A, or still can have something? Great question. I don't know. I have no idea. Welcome to evidence strong show. Nate, it's my pleasure to have you. Long time coming. Finally, go to... Thank you. That's part of your own mind. If you could briefly introduce yourself, that would be great. Sure. Yeah, like you said, my name's Nate. I am a current PhD candidate at Arizona State University. I did my master's at Cal State University Fullerton, which is probably where you kind of found some of my work when I did it with Dr. Andy Galpin. Part of my thesis there was a way of lifting studies, so we'll get into that at some point, I'm sure. The rest of my background is really the next to physiology and sports performance. So my undergrad, I got from Boise State University for undergrad and kind of at the very beginning of the story, I grew up being pretty active and being heavily involved in sports. I did baseball growing up, football. I played, you know, recreationally, basketball. I never played in an organized league or anything like that, but I definitely played football in like the U.S. Little League Pop Warner, which is like pre-high school and played through high school. And then once I got into high school, I got into the sport of track and field, where I then got into all-volting, the kind of gymnastics movement, hype, power, jumping, sprinting. I was never a distance runner. I just kind of hated running. I think I got my full worth of running during football season because we would just run till no end. I kind of found whatever activity within track and field that was the least running and overall was kind of one of them, which once I got into college, I realized it's not necessarily the case. We definitely ran a little bit more. It wasn't distance running, but it was a whole lot of volume of sprinting, which I am reluctant to give credit to because I definitely got faster and that definitely improved my performance. Go figure, specific training actually works. So I did that through community college and then I went on to Boise State and walked on to their to their track and field team, where I was lucky enough to oval there for one season but was a walk on nonetheless. And then once that was all kind of done and over with, I found CrossFit and weightlifting. That kind of brings us to today that essentially I've been so I've been involved in the sport of weightlifting for since then. So that was in 2014. I think I started weightlifting in 2012 or 13, and I'm kind of just competed since then. I hadn't really done much training, unfortunately, or competing in the last few years, just going through PhDs. It's kind of rough, but I've found other outlets for physical activity. I've gotten into rock climbing recently and a little more running on how that kind of went full circle. But yeah, so that kind of brings me to where we're at today. So I have a pretty lengthy background and physical activity. I was just strengthening coach and performance coach within that Wolf's timeline, where I was lucky enough to work with really great mentors. PJ Nesler, he's at XPT now, and then obviously during my master's degree, I got to work with Dr. Andy Galpin that gave me opportunities to do a little bit of mingling with people like Brian McKenzie, whoever else is kind of was through the revolving doors of Dr. Andy Galpin's labs, so a few athletes for sure. So that kind of got me started and then I went off to my PhD. And now I'm kind of clinical and more just kind of wet lab bench science, which is great. You know, it's got to provide me some really good opportunities at some point, hopefully soon. Stay tuned. But yeah, so that I think covers pretty much all the bases. I can go further if you have any other questions. How far you can you all PhD? Oh jeez, that's the age old question. I'm in my fifth year, kind of a long story short. I started out with somebody else as my mentor, worked with him for a year. He left ASU, and then I moved to another advisor mentor, and I've been with him for the last three years, gone four years. And so I'm hoping to finish up this academic year, so I should be done sometime in the fall. And then I will move on to the next step, which is typically postdoc that may, yeah, I don't know. We'll see what happens. There's some things in the works. So I don't want to add on a jinx. Any of the opportunity is just yet. So of course. So I invited you to talk about your study title extraordinary fast-to-reach fiber abundance in a lead weight lift test. So we will be talking about muscles and specific fiber types. And as an introduction to this topic, could you tell us what we have to narrow about muscles before we go into the study? Yeah, so I would say there's for most people, we know that there's slow twitch and fast switch fibers. Beyond that, there are a couple of subgroups of our fast switch fibers. We call them 2A and 2X. And along that same line, they exist in what is known as a continuum, right? So on one end, they contract right slowly, and on the other end, they contract fast, hence the names. And so these fibers are able to perform pretty tightly with metabolic processes. So if you look at slow twitch muscle fibers, they're pretty equipped to sustain muscle contractions for a really long time, which is why we see them endurance trained athletes or things like postural muscles of the spinal erectors or your sole-based muscle, those are all kind of always contracting to keep us upright. And then on the other hand, we have our fast switch fibers, which are more equipped to basically just contract really quickly. They're fast to fatigue, meaning they can't sustain very much contractions. They're really high power, which is great when we're talking about moving a lot of weight quickly, and supported weightlifting, sprinting, things of that such. So they're really good in that sense. And there are some drawbacks to fast switch fibers, and we can get into that as well. It kind of leads into some of my dissertation work. I don't know how far you want to get away from the sports performance side, but if you ask the questions, I'll definitely answer them. So that's kind of the basics. So we have our type ones and our type 2A and our type 2Xs. They exist on this continuum. And in fact, there's kind of in between those, there's also what we call hybrids, right? So basically, fibers can express more than one of these types. And these types are based off of a protein called mice and heavy chain. Bice and heavy chain is this big, kind of clunky protein that basically attaches itself to other fibers in your muscle, balls, and creates movement. This is what we call the sliding filament theory. And so our muscles are really cool in the way that they're able to kind of interact, pull in time on each other and create basically all sports movements, all of our daily physical activity movements. And so these mice and heavy chains kind of exist in different forms, right? So the forms kind of coincide with the types. So we have mice and heavy chain one is type one mice and heavy chain two ways, type two way mice and heavy chain two X is type two X. I would say probably in some textbooks, some of the older textbooks, they say 2B that we know is not to be the case that 2B is only in rodents, really. So we only see that those three main types type one, type two A and type two X. And so again, kind of going back, we have those in between hybrids, it can express both type one and two A or type two A and two X. In some cases, pretty rare, it'll express all three, type one, two A and two X, but that's kind of the, the gist of how things are kind of structured and organized on a muscle level. And there's plenty more to go into can, and I'll try to do that as, you know, kind of briefly and concisely as possible. But I think we'll get your listeners started at least. Awesome. I have a question about these functions and muscle fiber types, one A, two A and two X. Is that if the fiber is one type, can it switch to the other? And the hybrid ones, do they take sides at some point? Or they always are a hybrid? How should we think about these? Those are great questions. So we know that you can change or shift the proportions of your fiber type within a particular muscle. Typically, when we look at these, and these human studies, we're looking at the vassus lateralis, which is a muscle in your thigh, the outer thigh specifically. And so that one seems to be pretty indicative. One, a person might do on a daily, in their daily life, right? So you're, if you're walking, if you're running, if you're lifting weights, whatever your vassus lateralis is going to be affected to some degree. And so we like to think that this is a pretty good indication of what your physical activity might look like. And so this is fairly representative of someone's, you know, kind of lifestyle. Beyond that, we use the vassus lateralis for other several reasons. But namely, it's pretty easy to get to, you know, is on the front of the thigh. There's no major vessels, there's no major nerves that might get, you know, nicked when we're taking muscle samples out. And so with all that being said, the vassus lateralis is the most universally used in human research. There's also solace and gastrot, which is your calf muscles, right? So we use these muscles to try and figure out, you know, what role these fiber types have on either your performance or your metabolism. And so they can shift. There's been several studies over the last few decades that show, you know, with specific training, you can change your abundance of fiber type one way or the other, depending on the training style. So if you're doing endurance training, you can increase the number of type one muscle fibers. If you do more strength training, you can increase the abundance of type two a fibers. The only caveat here is you don't really know how or why this is the case, but you can't really change the abundance too much to X. There's only really been one study that has ever shown to X as being more than like 2% abundant in people. In fact, most in most cases, it's less than 1%. And most physically active people, we won't even see them ever pop up. So there's been one study today that has shown a sprint athlete that has had, I remember, the stat correct, but I think it was 24% type two X. And this is a world class sprinter, the world class spurtler. And so she followed Dr. Andy Galpin. He's mentioned this on several podcasts, I'm sure. But so where he got his PhD at Ball State University, they were fortunate enough to have a world class sprinter come into their lab. They took a biopsy and did a whole gamut of physical function on the muscle tissue. So they looked at, you know, traction speed, the mice and heavy chain break down fiber types. And they found that, you know, his fiber type was 24% type two X, something in the realm of like 20 30% type two a very little type one, and virtually no hybrid types. And so we know with athletes, these hybrids tend to not really show up very much. So essentially, as the abundance of these hybrids increases, a couple of things happen. One, you got a reduction and basically all the other fiber types, right? So they're taking up space, you're not gaining really more fibers. So if you're gaining more hybrids, that means the other fibers are being reduced, essentially. That means less overall type one, less overall type two A, and then depending on what type of population you're looking at, you're going to see more either two way two X, which is fast hybrids, and those seem to be more detrimental to overall metabolic and performance outcomes. The only thing we can say there is that, you know, some of the, a lot of this, a lot of the times these things aren't fully corroborated in research, because they're overlooked. It's really hard to, you know, isolate a thousand fibers and only 200 of them come out as hybrids. And so you can't get a full picture of what that impact is, but when you start to look at special populations that might be expressing more of these, then we have a better chance of explaining what these actually might contribute to your health function. And so that's kinder. Do you have any examples of populations that are rich in hybrid fiber? Yeah. So obesity is one of them. And so part of my research study currently, obesity tends to do a couple of things. One, it reduces the total amount of slow-twitch muscle fibers and increases. Historically, it increases fast-twitch fibers. And I say it that way because most of the literature doesn't differentiate between type two A or type two X. They just kind of plump together the fast switch fibers. So they say type one is reduced and type two, it is increased. Is that increased in type two A? Is it increased in type two X? It's kind of mixed. What I can say from really kind of gathering the literature, gathering the data is there's an increase in two X fibers, but this increase in two X isn't a true pure type two X because those typically exist normally, except for that one world-class printer. More often than they exist in these hybrid forms, two A and two X. And so we actually have a review paper that is in review. So we're waiting to hear back from our reviewers, whether or not we have to make any adjustments, but essentially, without giving too much away, we're making the argument that hybrids and fiber types in general are a big contributor to metabolic function. How big, hard to say, we need more data. Same thing in the case of hybrids, how much of that is being, how much of that is able to explain the sac rents and metabolic and physical function and obesity. Hard to say, we need more data. So I can't definitively say that these special populations have specifically more two A to S. We know that there's some hybrids in these populations because we've done some smaller stuff. The problem in most research groups don't do the same type of fiber type methods, and that kind of gets into a whole other conversation. If we look at kind of getting back to the way that we study, we did a lot of work to identify what these athletes possess. And so, remarkably, we found that they had a lot of these type two A muscle fibers, which explains a lot of A, their strength, because this is well established in the literature that type two A is pretty powerful as a contract. And so, it also seems like the length of time that was spent in some of these athletes participating in their sport were training for their sport impacted with the abundance of two A might be. So there was a pretty good correlation to the time participating and the abundance of these type two A fast switch fibers. And so what that tells us is A, yeah, system genetic component B, enough time to specific training will give you some results. So you have to remember that, you know, there's a long game to play when you're doing anything. And so the cumulative adaptation, so small adaptations that you get day to day to day, really add up over the long term. And so that I think was a big takeaway from the study for me, aside from, you know, just the sheer, remarkable expression of strength and power from some of these athletes and being able to explain some of that with these fast switch fibers. If you could walk us through the study, so you said a little bit that they were, YUPS is taken about how many athletes, what level they were in, and that we can go back to this. Yes, so we did this study back in 2017, I think it was. So I was, again, at Cal State University of Fullerton in Southern California, and we were very fortunate to have both the national weightlifting competition in the U.S. and the world competition in the same venue, which was literally right down the road from our university. And so as soon as we got word, the world was going to be there as well. We said we have to get there somehow and get as many athletes as possible. We did contact USA weightlifting. I can't remember if we got in contact with IWN to try and get some of the international athletes, but we definitely reached out to USA weightlifting. They were more than happy to comply. And so basically they were like, you can talk to whoever you want, if they're okay with it, go for it. And so that's basically what we did. We just kind of went on social media and was like, we're doing this study, everybody, and at the time, I was pretty well involved in the weightlifting community. And Dr. Andy Alpin is also pre-involved in CrossFit with Arbo Shrugged and kind of their platforms. And so she started talking about the study as well. And so we got a lot of people that were interested. The tough part was we had to shoot for kind of high caliber weightlifters. And so I literally had this whiteboard of just the top 10 athletes in each weight class. And I was just checking them off as I got in contact with them. Some of them were super interested, and some of them just wanted no part in that spine. And so the competition day finally came, and we ended up getting I think it was 21 total athletes. I don't remember the exact breakdown. How many of them were on the male side or female side? But we ended up bringing I think it was 21 athletes from all the various weight classes. I think we covered all of them on the female side at least. We missed a few on the male side. And then from that, we took our, basically, I just shuttled them back and forth in my personal car. And I was like, if you're interested, I will drive you. I don't even worry about transportation. I got you. So I shuttled them back and forth. And yeah, we asked it out. And I think it was a weekend, whatever weekend it was, that they were there. We're able to get 21 athletes. And then after that, it was just a few months of analyzing the tissue. We got people into the lab and then the biopsy. It's always tough when we start talking about biopsies. Anytime we're recruiting for these types of studies, because people hear the word biopsy and they're like, oh my god, and you're not putting them asleep. When you're doing this, what? It's a pretty minimally invasive procedure. We do local anesthetic. So essentially, we just kind of numb up about a quarter size area on your thigh. Most people, I would say, don't really recognize that your muscle doesn't really have pain sensors inside. You have pressure sensors, but you don't have pain receptors. Most of your pain receptors are in your skin on the more surface levels. And so when we actually put a needle in your thigh, it doesn't feel anything more than like a Charlie horse. Like if you ever like banged your leg against the corner of a table, or if you got checked in your side or need in your thigh or whatever, that's kind of the sensation you feel. And the way we do it, it's pretty quick. We're in and out of the muscle within a few seconds. So it's very, very fast, very minimally invasive. And so it's pretty, pretty easy. It's a pretty standard procedure in that sense. It's something that's been around for several decades, super safe, no issues. So these days, it's no different. We still use the same exact needle, same exact procedure for the most part. The only thing that might be different nowadays is some people take smaller samples and use it for things that are, I mean, this day and age, things are so much more sensitive as far as doing the analysis. And so we're fortunate enough that we can now take maybe a little bit less tissue and still get some of the same information. I have a question about taking a sample. If you cannot increase the number of fibers, you can just shift them with training, are you losing your strength when you're doing bios? No, we're taking about 100, 200 milligrams of tissue. That's like the size of a peak. So it's a very small amount, but also you're not growing more muscle fibers, but those fibers do repair, right? It's just the same as if you were to go and do a bunch of strength training and get super sore. Same exact process happens to recover that tissue. So you're still recovering, you're not losing any strength, you're not, there are so many people that are like, no, I don't want to lose my strength. I don't want to lose my muscle. I've worked hard with this, and it's going to grow back, eat a steak. So yeah, maybe a little bit better there. But yeah, so then it's not going to be any more detrimental than doing a really hard training session. But yeah, so getting back to the weightlifting study, so we took the biopsies, and then basically from the time we take the tissue, we throw it in some solution, that kind of makes it easy for us to isolate single muscle fibers in your microscope. And as I mentioned, we isolated somewhere in the realm of about 100 fibers. Yeah, yeah. So I like to think of it as kind of like pulling hairs from a ponytail that is just like bundled up, right? And so on one end, it's kind of open, you just pull the hairs out and be kind of all out. And they actually do kind of look like hairs, they're just much smaller, which is cool. So yeah, so, you know, we myself and in a few undergrads at the time, we all just kind of hashed out, you know, all these fibers. And then you do what's called electrophoresis, which basically you separate the different proteins in the muscle. In this case, mice and heavy chains based on the molecular weight, you know, we know that they're roughly the same size, but we formulated our process to basically separate very small changes in the size of these proteins. So that way we can image, you know, three different types of mice and heavy chain. And so when we run them through the gels, the different proteins will separate into these different bands. So you have a collection of, say, type two acts up at the top, then just below that, you have your mice and heavy chain to A. And below that, you have your mice and heavy chain type one. So we do that for individual fibers for everyone. So I think we ran somewhere around 2,100 fibers. And so that's, you know, a lot of samples to analyze. So that took, you know, several weeks, we meet a couple of months, I remember exactly. So you separate the fiber and then from that fiber, you take the protein. Yeah, so we basically grind it down and solve it into a solution. And then we put that solution in a gel, which we then separate by the size of the proteins that tells us, you know, what type that muscle is. And so it's a pretty standard procedure and a molecular biology to kind of separate proteins. Essentially what you're doing is you're putting your proteins in, you coat it with this electrolyte, and then you add electricity to the solution. The electricity then pushes those protein down at a certain rate. And the media that they're in or the gel that they're being pushed through is going to have some resistance. And so that is allowing for some of the smaller proteins to then get separated over time. And so you get these really nice kind of patterns of just lines, really, there's just lines on a piece of paper that tells us, you know, this protein weighs this much, this protein weighs this much. And so in the case of my heavy chains, we know they're about exercise. I mean, you don't need to know the exact size, but we know the size. And so from that, we know they're going to be around the certain area of our gels. And then we've done this, you know, for long enough that we also know that the top band is always 2x, the next band down is always 2a, and the next band down is always type 1. And so you do that for each of the fibers and then you basically pull them together and say, from this person, all of these fibers, 50% of them are type 1s, 40% of them are type 2a's, and the rest are hybrids or whatever. And so we did that for each of these, in each of these weightlifting athletes, I think some of them were upwards of like 90%, some of them are around 70%, some of them I think were actually around like the high 60, like 60% some around there. I have a question, can you see the honey grids on the gel, do they separate? Yeah, so actually what happens when we have a hybrid, so normally when you do single muscle fibers, you dissolve them into solution and you put them through that gel, and then they separate out, but when you separate them out, there's only the one protein sometimes, right? So if your fiber type for that one muscle fiber is type 1, you're only going to see one bit a hand, same thing for the case of type 2a, but this is why we speak, this is also why we add in a sample that has, you know, all three isoforms, so we know we can compare, say, okay, we know it has to be at this point, in the gel, that's 2x, and the next line down is going to be 2a, and we kind of compare across the entire gel and identify the different isoforms that way, so when we have hybrids, you actually will see multiple bands that will show a band where the 2a protein is at, and a band where the type 1 protein is at, or in the case of the fast hybrids, you'll see a band of 2x protein and a band of 2a protein, and so that's kind of where we get the idea that these these muscle fibers can coage, rest, or have multiple isoforms in one fiber, there is more recently, there's been some reviews and few dare I say argument that these hybrids kind of exist on a continuum within each fiber, that sounds a little bit confusing. What I mean by that is if you take one string, one muscle fiber, right, so a fiber is really just kind of a string, and so along that string, or that strand of cell, on one end you can have type 1, and then it'll transition into type 2a, there have been a few review papers that have shown kind of preliminary data to show that this does in fact exist, and this is kind of how they're structured, meaning it's not just a homogenous organization along the full length of a fiber, a fiber isn't just one 2a and they're evenly spaced throughout, they're, it's more the more likely to be the case that on one end of your or on say, if you look at your vastus lateralis muscle or even your bicep, right, so saying up here, you're more type 1, and as you go down, that muscle starts to change to 2x, or 2a, or whatever it is, and so there's still a lot more research that has to be done to really solidify this idea, but that seems to be the case in the case of hybrids, is that they don't necessarily exist, as this full fiber is a hybrid, and it's one end 2a along the full length, it's more likely to be the case that it's type 1 up here, and it's slowly transition into type 2a, and there's so quite like I said, there's... Wait, because you're blowing my mind, we have to, we have to, well, so hybrid is a possibly, so why do we have um... Yeah, you think about a strand of hair? Yeah, yeah, yeah, so the closer to your scalp, it could be type 1, and the further away, it could be type 2a. Okay, so, and if we classify the fiber as, let's say, pneur to a, will it be all the way to a, or still can have something? Great question, I don't know, I have no idea. This is strong. It is kind of shocking, and this is kind of a revelation, I think, that is starting to come to light, is we aren't really sure these pure muscle fiber types exist. We make so many assumptions with these studies that we definitely assume that the fiber is a pure type through and through. We don't know how to be the case definitively, and most, I will say, in most active individuals, this is more than likely the case, because we've done studies where we take, you know, a biopsy, a pitter, then like an inch down, an inch down, and an inch down, and they all are roughly the same. Okay. Now, again, we're making assumptions because you're clearly not taking the same fiber up here as you are down here and down here and down here, but the relative proportions of the fiber types are roughly the same. So we can make, we can safely assume that in active individuals, they're mostly pure type, along the length of the fiber, it's probably not transitioning really anywhere. An individual has hybrids, that's not the case. And it seems more likely that if you have any hybrids, it's transitioning across the entire length of the muscle fiber. And so, if you think of muscle fibers, again, they're single cells that exist across the entire length of your muscle. And so that too can also exist in a hybrid, right? Do people biopsy those or test the fiber type? Not really. I don't know for sure, but, I mean, hypothetically, if there was a hybrid in that muscle, it would transition across the entire length of that muscle. Again, kind of a newer argument as far as, you know, within my field of obesity, there seems at, and a few other disease states like, you know, I say disease, but enough aging isn't necessarily a disease, but we do see more hybrids in aging as well. Things like sarcopenia, the loss of muscle mass due to age, or sarcopenic obesity, loss of muscle mass through obesity, we definitely see more hybrids in that. We've, I think there's even, you know, like PCOS, polycystic ovarian syndrome, there's, there's changes metabolically, which means that muscle has to teach too, right? So anytime there's changes to metabolism, that has to affect your muscle, because your muscle is the one of the most metabolic organs that we have in our body, right? Because it's always active, it's always consuming some level of nutrients, right? So you're always having to burn either fast or, or sugars. This is why exercise is great for diabetes, because your, your muscle has to consume those fuel sources in order to live. And so anything that affects your metabolism has to also affect your muscle. And anything that affects your muscle has to also affect your metabolism. And so this is more or less the argument that we are trying to make currently in the field when we're talking about hybrids. This is very important to digest that. Yeah, yeah, I know that it's not a lot to digest too. If that's the case, it, it, it puts exercise in general in a totally different light. It's not for any superficial reasons, but like the influence of exercise on metabolism and how it's all interconnected. And absolutely. For any disease that has metabolic component, exercise could potentially be mediatorful, whatever changes we're trying to make. Absolutely. Yeah, I mean, exercise we've known for decades that it's super important for, for, you know, the longevity. We know, you know, doing aerobic exercise massively reduces your risk of coronary artery disease, diabetes, resistance exercise, massively reduces your risk for those things as well. But even more so as we age, you know, there are studies that show resistance exercise is almost more, if not as important as aerobic exercise as we age because it gives us the strength to then perform our daily activities. So if you think of aging, everybody knows someone who's in their older age. And so as we age, they tend to need some level of assistance or you reach a certain point in your age where you no longer have the strength to, you know, carry the groceries in yourself, or, you know, take that one trip that everyone always distresses to take multiple trips. And so you reach a point where your muscle starts to just atrophy. And there is, that is something that is kind of inevitable, inevitable, are going to lose. I think it's about like three percent or something like that of your, of your muscle mass. As with each decade, I think I forget the exact, the exact stat. But once you reach, this is where it kind of gets tricky. Once you reach a certain age, I'm just gonna say I serve an age because it's not very clear. But most people I would say probably say like, you know, once you reach like 3540, you start to see a deep line. Some people start lifting out 40 and see massive improvements. So that's, this is why I say, you know, it's kind of hard to say. But certainly once you get into your sixties, maintaining muscle mass becomes very difficult. And so it becomes more and more important to lift at a younger age and maintain that muscle mass. Because as you age, you want to prevent falls at the end of the day, right? So older people tend to trip, stumble. If you don't have the muscle strength to then catch yourself as before you fall, then you get broken ankle, broken hip, broken, you know, collarbone, whatever, or you trip, fall and hit your head. And now you have a concussion or some other brain contusion. And so that can put somebody in a hospital. And once you're hospitalized, you put yourself at risk for a lot more other than, you know, what you're in there for the first in the first case. So preventing falls is a huge thing, I think as we age, and strength training, as well as aerobics, definitely a place of role in that. But it seems like strength training is super important as we age, whereas, you know, aerobic training definitely might be more important as we are a little bit younger. But you should definitely be doing both, definitely be doing both, because both of those are going to impact your muscle and the metabolism in some way, shape, or form, more than likely somewhere in the realm of type ones in the type two ways that have, you know, more abundance of things that we find beneficial mitochondria, different enzymes that process fats, different enzymes that process sugar, I think different proteins with an air muscle that are then shuttling your sugars around your body, or shuttling, you know, fatty acids around your body. All of that is, to some degree, tied to your muscle fiber type. Wow. Yeah, I know. There's, there's, you know, from the weightlifting coach point of view, we think type two, fast twitch, that's what we want, the power generation in short time, we want to leave the big weights above the head fast. Yeah. Well, there's so much more to it. There's, yeah, there's so much more to it. It's not just about letting massive weights over your head, which is, I think, an incredible feat of the human body. Human, the human experience, I'm not one to say, you know, it's meant to be one way or the other, but human physiology, definitely a little bit of both worlds. You definitely want some strength. You definitely want some aerobic capacity, right? So if you want to live a healthy, long, happy life by happy, I mean high quality of life where you're not always sick. You're not having to do with these medical issues. Of course, there are certain things that just are unavoidable as far as health, genetics, things that you're predisposed to, things that are in the environment. So, as long as you're taking care of those bases, where you're doing aerobic exercise and you're doing strength training, you're going to limit the rest, essentially. And so that's something I think I've come to appreciate more in the last several years, kind of post-4-10 post-weightlifting study. Awesome. Let's go back to the study though. So you just took one fiber, run it smooth, another fiber, run it through, and 110 times for each person, each fiber was run separately. That's mind-blowing. Yep. So each of those fibers would run separately, which again, it took several weeks, if not a couple of months. I think by the end of it, you know, we decided, we basically found that the fibers, they were extremely abundant, but also we had this nice correlation with, again, participation time. Those were the kind of two main takeaways of the paper. Aside from, well, we didn't really measure men and women, and we didn't have enough men that participated, unfortunately. But for the women, this is kind of the first time female athletes were really hyper-typed at his degree, which was great, which was pretty easy, because that's all I had to say. Most women were like, "Hell yeah, sign me up," which made my job a lot easier, but also, I mean, this clearly has been super impactful because it's kind of changed my career as far as the attention this study has brought. So again, very fortunate to have had the opportunity to do it. So two main findings. One was weightlifters have extraordinary amount of type 2 muscle fibers, and the muscle type. It tends to correlate pretty well with the time that they participate. So how do you know that the correlation is the correlation with the training age rather than with the level? Because what I'm hitting is what was first? So are these athletes elite because they have the fibers, or they work hard enough to get them to change their fibers so that they can perform at the highest level? Yeah, I don't have a very clear answer, unfortunately. We didn't collect a whole lot of data to really answer that definitively. The only thing we really had was we asked them how long have you been participating in strength training or weightlifting, and then we kind of ran those numbers with their fiber type proportions. And so this is why I say they correlate pretty well with the length of time that they participated in, because that's what we actually measure. How much of that is, you know, what they started out with? I have no idea, and we would have to do further research in order to really answer that. What we can say is with the information we have, however long that they participate in the sport seems to be a pretty good indication of what the fiber type -- or sorry, not their fiber type, but necessarily they're glo, right? So people who participated the longest tended to be more elite as well. There are a few outliers, I say outliers, but there are a few people that didn't quite follow that pattern, but in general, that seems to hold true. I think we covered all the bases. Do you have anything you think is important, and I didn't ask about from your study? No, I think we covered pretty much everything in the study. I want to ask you, did you read the Botella study on Mitra-Hundria? Yes, I did look it over. I will probably have to pull it up to refresh my memory. For the Patreon community, Evidence Strong has, I'm re-bearing master classes, and I thought the study fascinating, and it is done on power lift tests, because even in terms of muscle fibers, there are some differences between power lift tests and weight lift tests. With this in mind, I'm wondering how likely it is that the findings they had for our lift tests would have mine to weight lift tests too. Right, yeah, I know this one was kind of interesting for me and it's kind of hard to, obviously, this paper shows some kind of, it's fairly new to, at least, I haven't done a full literature review on the topic, but judging by what the report in this paper, it seems like the Mitra-Hundria has become more efficient, and that's what we're seeing here, so that increased Mitra-Hundria surface area, and the Chrystae. The Chrystae basically is like the membrane on the inside of the Mitra-Hundria. Exactly, all those little folds inside the Mitra-Hundria, which gives space for different enzymes and proteins that interact in different processes, like what we call electron transport, basically for oxidative possible relation, or the use of oxygen to create our energy, and so the more surface area we have, the more opportunity for a lot of these interactions to occur. Chemistry is physics, physics isn't necessarily chemistry, but chemistry definitely relies on probability of interactions. You have all of these different molecules that are interacting in our bodies. The more we have, the more abundant these enzymes, molecules of oxygen, these molecules with glucose, the more we have, and the more their actives, or the more they are moving around, or the faster they're moving around, then the more interactions we're going to have. The more interactions we're going to have that we have, the more byproducts we have of whatever it is that's interacting, and so in the case of metabolism, you know, if we have kind of a perfect scenario, the right temperature, the right pH, the right abundance, then we have these really efficient processes, and so when you have more surface area on the Mitra-Hundria, that's kind of increasing the efficiency of the Mitra-Hundria, which allows us to produce either more energy or aerobic exercise, or in the case of these power lifters, we're able to then perform these very strenuous contractions for a longer period of time, and if you think about powerlifting, these competitions can be a fairly long amount of time, right? So you're competing over an entire day, these super high strengths demanding activities, and so being efficient and creating energy to then produce those contractions is important. I think that that's kind of mounted away from this paper, or at least that's my main takeaway from the paper is that it seems through this training the Mitra-Hundria tend to become more abundant, which is Mitra-Hundria density, or the surface area and the Chrystate density, they're both abundant and efficient at creating energy, which allows for, you know, more sustained activity for whatever activity it is that you're demanding of the muscle, because at the end of the day, that's kind of what we're aiming for, adaptation is just the summation of a bunch of a cute stimuli, right? So what I mean by that is what you are tomorrow and the day after and the day after is a result of what you're doing today. And so this paper here tank really doesn't say that obviously specifically, but increasing Mitra-Hundria surface area and the density and skeletal muscle from the athletes, it seems that's probably the case, and then how we apply that to weightlifters, I would say they're probably pretty similar. The style of training is maybe a little bit different, but there's still, you know, weightlifters are training depending on how often you're computing or what caliper you're at, you're training for, you know, 90 minutes to two hours, sometimes three hours, sometimes you're training for like an hour or two, three times a day, and so you have to have the equipment or the biological equipment in order to do that, and so Mitra-Hundria is forced, you're going to be part of it, and so I would suspect that this is probably going to be a similar case of weightlifters, where you're adapting your energy supply resources to help you through some of those training, those training labs. So the research you did on muscle fiber type is based on the protein content in the fiber. The research they did was based on extracting Mitra-Hundria from the tissue, so it's, I understand it is very hard to compare, because they are, you measure different things, but possibly because fast-to-reach fibers and slow-to-reach, they will work differently, they will have different demands on energy possibly as well. Yeah, so in general, type 1 fibers tend to have the most abundance of Mitra-Hundria because, again, you're having to produce a lot of energy in order to sustain contractions for a long amount of time. Typically with aerobic, aerobically-trained athletes, you have a large abundance of capillary density, Mitra-Hundria density, and all of the associated enzymes, so such as syntheus, which is involved in breaking down glucose, beta-adroxyl, I forget the beta hat, I forget the full name, but all of these enzymes are involved in these biochemical processes to create ATP, and they're pretty closely tied to the fiber types, and once that review paper comes out, I'll send it your way and you can talk again maybe, also give a little more details. Your fiber types are very much linked to some of these processes, specifically your Mitra-Hundria. In fact, there's some research done, I feel where he's at now, but his name is Ryan Clancy. He does a really cool research that looks, basically he images, takes electron microscopy images, that takes me really fancy microscopes, and images your muscle, and he's now imaged, basically the entire network of a chunk of muscle to show the Mitra-Hundria network, basically it's structured in a way that is kind of this interlinked web, rather than what we typically think of Mitra-Hundria as these little kind of of oval shape or like lima beam shape, that can be the case, but more often than not in muscle, there are these elongated structures that are then interconnected through these what we call junctions, and so that allows us to increase the surface area for all of these enzymes to work, all oxygen to interact, electrons to get passed around, that way it gives you, you know, a better ability to do things like process fatty acids, process sugars, all the metabolites that go along with us, so if you're looking at lactate, shuttling lactate around the body, using it for fuel, things and that sort, and so fiber type is absolutely linked to fiber for Mitra-Hundria abundance, but it seems type one and type two are very similar in the abundance of Mitra-Hundria, which is why they said, I think, in the paper that the abundance was not really changed, but the density and the crusty, basically the structure of the folds was different, and so, again, what that tells me is that they become more efficient, probably in the processes of using the glycolysis and breaking down sugars, they probably don't do a whole lot, that would be all that similar to aerobic capacity, so is there some part of it that's going to be similar, sure, but maybe not the same, I'm not super well-versed in mitochondrial literature, but I know that increasing the surface areas or sure going to increase the efficiency of their function, meaning that they're just going to be able to process a whole lot more fuel resources in order to create ATP, and so, when we're talking about kind of comparing creatures, they will waste less because they can go through everything that comes their way, because I would say that they probably recover faster or they're able to basically break down, so everybody has stores of fat and sugar, right, so your liver stores glucose, your muscle also stores glucose in the form of what's called glycogen, and so, the faster you can basically pull a glycogen from either your muscle tissue or your liver, then the faster you're going to have that ATP ready for your muscle to actually use, and this is kind of what I mean by there, it becomes more efficient, it's faster in processing, going from glycogen down to glucose and creating ATP, and I would suspect that this is probably a very similar case that we look at from power litters to weightlifters, because they have the molar, I would say, abundance of fiber types, so power litters, historically, there's been a few studies that have looked at power litters and their fiber types tend to be pretty, pretty similar that of weight lifters, there's someone whose aerobic are strength trained, and so, a power lifter might do a lot of strength training and have obviously bigger muscle fibers, most of those are probably going to be type 2a, there are some cases where some bodybuilders have more aerobic fibers, but those who rub it with those type 1 fibers just are the ones that are bigger, is it, you know, this kind of comes down to, again, this is genetic, is it style of training, it's hard to say, you know, if you look at the style of training of some bodybuilders, some of them do a lot of high rep stuff that is, quote unquote, aerobic or endurance, the muscle endurance might, you know, and I think Brad shown helps as several papers on kind of training style, influencing fiber type transitions as well, namely, increasing the number of reps per set might, you know, target the hypertrophy of type 1s, and so, we probably see this by going, and so, if you're doing more strength training where you're in the realm of what I would say quote unquote traditional strength training, where it's like, you know, anywhere from 3 to 5 reps, which is kind of your standard, you're probably going to have increased hyperic feed in type 2a's, and with weightlifting, they are almost exclusively lifting 1 to 5 reps, and so, on that note, I think they're very similar findings in this paper are probably going to be pretty similar, if we did it in weightlifters, where we would see an increased surface area and density within the mitochondria, that is, again, at the end of the day, just saying your mitochondria are now more equipped to create energy for a longer period of time. So, again, weightlifting, powerlifting, they're kind of all day activities, you know, you're warming up, you're working up to your main list, that takes maybe, you know, 30, 45 minutes, and then depending on the competition, maybe you're lifting an hour, and then you have to go take a rest, and then warm up again for your next left. So, you know, over the course of 2 hours for weightlifting, sometimes 3 hours for weightlifting, powerlifting, I don't really have experience computing on that one, but I know it takes a long time, because you're doing bench squatting doublets, so, I suspect there's similar attacks on the metabolic systems, and so, we're probably seeing a similar thing within the mitochondria. I hope that answers the question, or the answer is any potential questions with that. Okay, so, heavyweight athletes have high fatmas and high muscle mass, so they possibly would have characteristics of obese person, and elite athlete, would you have any comments on how it will influence their metabolism? Absolutely, so great question, and one that I can't answer outright, but what I can say is, from the data that we have in the weightlifting study, we do report some of the heavyweight athletes as having more hybrids, and so, had a relating that, within the heavyweight athletes that we tested, it seems that they are more abundant in the hybrids, whether or not that's because they are in a quote unquote obese category, it's hard to say, because we didn't specifically test their body mass, we didn't specifically test their fat mass, we just know that they're in the heavyweight classes for weight lifting, and then we obviously know their fiber type. Now, being within the obesity, clinical landscape, while kind of field, I can say that obesity tends to have more hybrids. Again, I don't really know whether that's driven by fat mass, driven by sedentary lifestyle, surely weightlifters who are in the heavyweight weight class are well trained, but if you know anything about weightlifters, they lift, and they go sit for the most part. Some, maybe some other weightlifters might get mad at that, but certainly not all of them, some of them still are, you know, and some tend to still stay somewhat fit by running a mile. At the most, I would say if you can't run a mile, you're on a bad track, so even if you're a weightlifter, running a mile is not going to hurt, it's not going to take away your strengths games, I know there's this talk about aerobic training and resistance training, you've got to focus on one, or you're going to have some interference effect, it's so small, don't worry about it, do both, but back to the matter of hand, yeah, I think there's definitely something to say about fat mass and hybrids. I don't know entirely whether or not one's driving the other, but it's definitely something that is worth investigating and something that I do feel deeply interested and passionate about, and we'll one day answer that question, but until then, the only thing you can say is there it is a relationship, I just don't know exactly what's causing it. Thank you, I have two short questions, easy ones, the first one is what is your favorite color? I would say, as you asked me, when I was in high school, well, read mostly because their school colors had red glitter in it, I'd say now is more likely blue or gray, I tend to wear those colors a lot more, it's more what kind of blue? I'd say any blue, I mean, I feel like the best scenes that we have on this earth have some form of blue in it, and that's kind of why I'm drawn to that color these days, whether it's blue skies or blue oceans, whatever, yeah, hard to beat those. Very enough, and the last question where people can find you to ask a question or just follow what you do. Yeah, so like Instagram, I always forget what, you can just type in my name Nathan Serrano, there's either, I think it's underscore Nathan, underscore Serrano, something like that, you can find it, I'm sure, and post it in the notes. Yeah, that's actually how you said, yeah, let me tag me or whatever, and then you can also find me on Twitter, the same thing, it's naysm-serrano, I believe, not super active on either of them at the moment, I do plan to get a little more active on probably Instagram, maybe Twitter, we'll see, but I would say the main platforms, otherwise, you can find me on Google Scholar, and yeah. Awesome, thank you so much for today and I do, we come up a lot, I learned. It was a lot, I know. Yeah, I learned the things I didn't know, I needed to know, now I'm very grateful. Oh, well, I'm glad to point the things out. It was definitely a pleasure to be on and talk about all these things, there's a lot that I've definitely been learning myself over the last few years, Ph.D., a whole other animal from Massey's degree, so it's been great learning all these things and kind of putting it together, even though I've been in more clinical research these days, I've just really still found ways to explain, or at least relate it to sport and performance, so yeah, glad to be invited, I'm glad to kind of add to the growing body of athletic performance all edge here. No, thank you, thank you so much for your service. (clap) [BLANK_AUDIO]