Understanding Muscle Fiber Types and Training

Have you ever wondered why some people excel in endurance sports while others dominate in sports that require short, explosive movements? Maybe you've even been training with a friend and noticed that you might be naturally better at some forms of exercise while your friend might be better at others. Well, part of this has to do with the makeup of your muscles. Each of your muscles is made up of different muscle fiber types that influence how well you perform in certain types of exercises and sports. And you may have even heard of fast twitch muscle fibers, versus slow twitch muscle fibers. So today we're going to dive deep into skeletal muscle fiber types, talk about the pros and cons of each fiber type, discuss how they adapt to exercise, and also discuss if you can do anything to change them. It's going to be a twitchy one, so let's do this. So let's start by taking a look at the cadaver dissection and use a specific muscle as an example here. Here we have the vastus medialis, one of the four muscles that makes up the quads. And what is important to understand is that each skeletal muscle is made up of hundreds to thousands of skeletal muscle cells, also known as skeletal muscle fibers. And I'll just refer to them as muscle fibers from here on out. But if you were to look at all of the muscle fibers making up this vastus medialis, or any of the muscles throughout the body for that matter, you would see that not all the muscle fibers are the same. Some of them would be considered vastwich. and some of them would be considered slow twitch. Like the quad muscles could be made up of 50% fast twitch and 50% slow twitch. Now the reality is there's a little bit more to it than just classifying all fibers as either slow twitch or fast twitch and I'll cover that in just a second. But the proportion of fast twitch muscle fibers to slow twitch muscle fibers in each muscle is determined by certain factors, one of those being genetics. So for example, some people can naturally have a higher percentage of fast twitch fibers and so they often excel in sports or exercises that are more explosive in nature such as jumping or sprinting and even heavy resistance training and on the flip side some people can naturally have a higher percentage of slow twitch fibers and are better at activities that require endurance such as long distance running but what we are going to learn is that this isn't completely set in stone based on the type of training that we choose to participate in Not only do the fibers that we have adapt but we can also see some conversion of one fiber type into another. And another thing I do want to point out is that even though we do see variation in the percentages of fast twitch fibers to slow twitch fibers from person to person and even though we can get some conversion based on our training, we do all share some general commonalities with certain muscle groups. And what I mean by that is muscles that are considered postural muscles that are found in the neck, back, Core and even certain leg muscles tend to have a higher proportion of slow twitch fibers whereas muscles of the shoulder and arm and even certain leg muscles have a higher proportion of fast twitch fibers. So why is that? Well, this has to do with the characteristics of the fiber types or what you may even consider to be like the strengths and weaknesses of each muscle fiber type. So let's get into some of these amazing details starting with the slow twitch fibers. Slow twitch fibers are actually referred to as slow oxidative or type 1 fibers. Slow oxidative is actually a pretty great name because these fibers contract with less velocity and they utilize oxidative phosphorylation which is an aerobic pathway utilizing oxygen within the mitochondria to generate ATP. So these muscle fibers have a ton of mitochondria and many tiny blood vessels called capillaries and by having a high number of capillaries. This allows a lot of oxygen, glucose and fatty acids to be delivered to these fibers. They also have a very high myoglobin content which is a protein similar to hemoglobin that binds and stores oxygen within these slow oxidative muscle fibers and myoglobin actually gives off a red color. So the slow oxidative fibers are also sometimes referred to as red fibers whereas fast twitch fibers are sometimes referred to as white fibers. But this will also help us to understand the strengths of these slow oxidative or type 1 fibers. Because of their high mitochondria and oxygen content and their extensive blood supply, this makes these fibers extremely resistant to fatigue and so they are excellent for maintaining posture and aerobic endurance type activities such as distance running, cycling and swimming. And so if you were to spend a lot of your exercise time doing endurance type activities or even lightweight resistance training, and you notice that your fitness in these areas improved this is in large part due to these muscle fibers adapting by increasing the size and number of mitochondria as well as the number of capillaries which translates to improved endurance but an adaptation that What you don't see as much with these fibers is a substantial increase in size or what is referred to as hypertrophy and so these muscle fibers have the smallest diameter of the fiber types which explains why if you see a marathon runner they typically aren't going to be huge from a muscular standpoint and this also reminds us what these fibers are not really built for and that again was they don't contract with as much velocity as the fast twitch fibers and therefore are not capable of generating as much force. And so now let's move on to the fast twitch fibers which are known as fast glycolytic or type 2x fibers. Fast glycolytic is also a great name because these fibers contract with the most velocity and they generate ATP very quickly through anaerobic glycolysis which is the breakdown of glucose in the absence of oxygen. And unlike the slow oxidative type 1 fibers, the fast glycolytic fibers have few capillaries and few mitochondria and also have less myoglobin. So they tend to have a pale to white appearance which is why they are sometimes referred to as the white fibers. However, these fibers tend to be the largest in diameter and as we've already covered, contract with the most velocity and are capable of producing the most force. They also have an incredible capacity to store glycogen which is the storage form of glucose which makes sense because they primarily use glycolysis, the breakdown of glucose, to produce ATP. So when someone participates in exercises like heavy resistance training or explosive movements such as jumping and sprinting, these fibers will adapt by getting larger as well as increase their capacity to store glycogen. But as you've probably already guessed, even though these fibers can contract with more velocity and produce more force, they can't sustain this for very long. Creating ATP through anaerobic glycolysis is very fast, but anaerobic glycolysis only produces two ATP molecules per molecule of glucose. which isn't a lot and won't last very long. So these fast glycolytic fibers, yes, produce a lot of force, but their resistance to fatigue is much lower than the slow oxidative fibers. And just to give you some comparative numbers here, a slow oxidative fiber can take one molecule of glucose in the presence of oxygen and funnel its products into the mitochondria and make about 36 ATP. But again, these are trade-offs here. Even though the slow oxidative fibers Make more ATP per molecule of glucose. It takes many more steps to do this and therefore is a much slower process of creating ATP. Now a lot of times people will refer to muscle fibers as just either fast twitch or slow twitch but as I hinted earlier, there's more to it than that and there's actually another really cool fiber type that is worth learning about and that is the fast oxidative or type 2a fibers and sometimes they're even referred to as fast oxidative glycolytic and it's Probably not going to surprise you that I'm going to reference the name of these fibers as also being named well because as the name implies, these fibers contract with more velocity than the slow oxidative fibers but not as fast as the fast glycolytic fibers. But what is also interesting is that these fibers primarily rely on aerobic metabolism for energy which makes them more resistant to fatigue than say like the fast glycolytic fibers. They can also switch to anaerobic metabolism when needed and utilize anaerobic glycolysis allowing them to produce ATP at a faster rate and enabling quicker and more powerful contractions than again the slow oxidative fibers. And this is sometimes why they're referred to as fast oxidative glycolytic rather than just fast oxidative because they can do a little bit of both. You could kind of think of them as the intermediate or the hybrid fibers with the ability to do a bit of what each of the other fibers can do. Another characteristic of the fast oxidative fibers is that they have a lighter pink color that comes from a lower myoglobin content compared to the slow oxidative fibers. But they still have more myoglobin and therefore a better oxygen supply than the fast glycolytic fibers. The fast oxidative fibers also have a moderate number of mitochondria and glycogen stores and all of these characteristics give them an advantage for sustained but more moderately intense endurance activities. such as running or swimming and even though they don't generate as much velocity and force as the fast glycolytic fibers they are more resistant to fatigue making them ideal for activities that require both endurance and a moderate level of speed Now what is also interesting is how your body decides which fiber type to use and it pretty much depends on the task. In general, if you're doing something light like maintaining posture or lifting a lighter weight, your slow oxidative fibers are the first to be recruited and if you need a little bit more force then your fast oxidative fibers are activated but when maximum effort is required, say you're sprinting or lifting a heavy weight, your fast glycolytic fibers are then called into action. And I actually have another video where we go into motor unit recruitment, where we discuss recruiting muscle fibers in even more detail. So I'll link that at the end of this video. So we kind of went into a lot of information there. So Jeffrey and I think that we should finish up by summarizing what we've discussed. And then more importantly, apply it to your own health and fitness. And I think this chart really helps us to summarize the characteristics and differences of each fiber type. So we've got our slow oxidative or type one fibers. They have a large amount of myoglobin, many mitochondria and capillaries. and because of the large amount of myoglobin we have that red color. They have this high capacity to generate a lot of ATP through aerobic respiration but again through aerobic respiration that takes more steps and therefore takes more time and so their rate of ATP use is slower, their contraction velocity is slow, however they have that extremely high resistance to fatigue and so these muscle fibers are great at maintaining posture and for aerobic endurance type activities. Then we've got our fast oxidative sometimes referred to as fast oxidative glycolytic or type 2a fibers. These are our hybrids. They can do a little bit of both or a little bit of everything and so we have this intermediate amount of myoglobin. They still have a good amount of mitochondria and capillaries but because of that intermediate amount of myoglobin they start to have this pink color. Now as far as generating ATP in intermediate capacity by both aerobic respiration and anaerobic glycolysis. And because they can do anaerobic glycolysis, they can have a fast rate of ATP use, but an intermediate contraction velocity and an intermediate level of resistance to fatigue. Now, these muscle fibers are great for like moderate to high intensity aerobic endurance. So maybe if you're jogging at a more slow pace and then you started picking up the pace, you'd start to fire into some of these fibers. Think also longer sprints, maybe like 200 to 400 meters. And then intermediate resistance training would also start to fire into these fibers as well. And then we have our fast of the fast, the fast glycolytic or type 2x fibers. They have a small amount of myoglobin, few mitochondria, and few capillaries. And because of the small amount of myoglobin, they have that white to pale color. Now, they have a low capacity to generate a lot of ATP. However, they can make the ATP really quickly. The small amount that they do make, they can make it really quickly through that anaerobic glycolysis. And so their rate of ATP use is fast. Their contraction velocity is going to be fast. And their resistance to fatigue, however, is going to be much less than the other fiber types, especially much less than the slow oxidative fibers. But they're great, sorry Jeffrey, I'm getting in your way here, for rapid intense movements of short duration. Think like full-fledged sprints, like a 100 meter dash, and then also heavier resistance training. Now here is what is very interesting about all this. Yes, we do have a genetic predisposition to have certain proportions of muscle fiber types. And when you train in a certain way, you will create adaptations in the fibers that you already have. So if you do lower intensity endurance type activities, you'll see adaptations in your slow oxidative fibers. If you start to increase the intensity and do more moderate endurance type activities and even some moderate loads of weight training, you'll start to get adaptations in your fast oxidative fibers. And then of course, if you do even higher intensity weight training with even higher loads. and or explosive exercises like sprinting and jumping you'll start to see adaptations in your fast glycolytic fibers however your muscle fiber types are not completely set in stone and while you cannot change your genetic makeup the types of exercises that you participate in the most can influence the conversion of one muscle fiber type into another now this obviously will take time and consistency but if you were to spend most of your time doing sprinting, jumping, Olympic lifting, you'd see some of these fibers on this end start to convert into more of the fast glycolytic type. And on the flip side, if you spend more time doing steady state long duration endurance activities like distance running, you'd start to see fibers on this end converting more towards those slow oxidative type. And there have been some fascinating studies with monozygotic twins, which is a fancy pants way of saying identical twins. But one particular study I'm thinking of. took biopsies of the quad muscles from each twin and the one twin that had participated in endurance training for years and years Nearly 90% of the quad fibers were more of the slow twitch variety while the twin that had not participated in long-term endurance was closer to 50-50 fast twitch to slow twitch. So it really helps to show that yes, genetics does predispose you to be better at certain types of exercises in sports but you can stimulate some incredible adaptations with consistent training in types of exercises and activities that you may enjoy more than others. As some of you may know, we launched the Institute of Human Anatomy back in 2012, and it's been an amazing journey every step of the way. We've taught millions of people through our videos and are looking forward to educating even more about the wonders of the human body. I'm so personally grateful for every comment, share, and view from our audience, and the worldwide support is truly mind-blowing. We would not be able to keep creating if it weren't for all of you. Back in July, you may have also known that we launched an anatomy app. It's been an incredible few months of testing, and taking feedback from our users inside the community. So now I'm thrilled to announce the relaunch of the Institute of Human Anatomy membership community app with new pricing and new features. We believe we've created something truly special. In this revamped app, you'll find monthly live sessions where we dive deep into different body systems, access to me 24 7 with our new AI assistant to answer all of your burning anatomy questions anytime over 140 comprehensive study guides and quizzes. Monthly Ask Me Anything livestreams where I'll get to answer your burning questions in real time. Special interest groups designed for healthcare professionals, fitness enthusiasts, students, educators and just regular old anatomy nerds. And lastly, a structured learning path to keep you engaged and learning. So whether you're looking to enhance your professional skills, ace your anatomy class, chat with anatomy nerds like you, or simply satisfy your curiosity about the human body, this app is definitely for you. So join us today in our incredible community by checking out the link in the description below. We have new pricing that you don't want to miss. Thank you again for all of your support. I'm so excited for you to check out our community where there's no limit to this anatomical awesomeness.

Each of your muscles is made up of different muscle fiber types that influence how well you perform in certain types of exercises and sports. And you may have even heard of fast twitch muscle fibers, versus slow twitch muscle fibers. So today we're going to dive deep into skeletal muscle fiber types, talk about the pros and cons of each fiber type, discuss how they adapt to exercise, and also discuss if you can do anything to change them.

It's going to be a twitchy one, so let's do this. So let's start by taking a look at the cadaver dissection and use a specific muscle as an example here. Here we have the vastus medialis, one of the four muscles that makes up the quads.

And what is important to understand is that each skeletal muscle is made up of hundreds to thousands of skeletal muscle cells, also known as skeletal muscle fibers. And I'll just refer to them as muscle fibers from here on out. But if you were to look at all of the muscle fibers making up this vastus medialis, or any of the muscles throughout the body for that matter, you would see that not all the muscle fibers are the same. Some of them would be considered vastwich. and some of them would be considered slow twitch.

Like the quad muscles could be made up of 50% fast twitch and 50% slow twitch. Now the reality is there's a little bit more to it than just classifying all fibers as either slow twitch or fast twitch and I'll cover that in just a second. But the proportion of fast twitch muscle fibers to slow twitch muscle fibers in each muscle is determined by certain factors, one of those being genetics.

So for example, some people can naturally have a higher percentage of fast twitch fibers and so they often excel in sports or exercises that are more explosive in nature such as jumping or sprinting and even heavy resistance training and on the flip side some people can naturally have a higher percentage of slow twitch fibers and are better at activities that require endurance such as long distance running but what we are going to learn is that this isn't completely set in stone based on the type of training that we choose to participate in Not only do the fibers that we have adapt but we can also see some conversion of one fiber type into another. And another thing I do want to point out is that even though we do see variation in the percentages of fast twitch fibers to slow twitch fibers from person to person and even though we can get some conversion based on our training, we do all share some general commonalities with certain muscle groups. And what I mean by that is muscles that are considered postural muscles that are found in the neck, back, Core and even certain leg muscles tend to have a higher proportion of slow twitch fibers whereas muscles of the shoulder and arm and even certain leg muscles have a higher proportion of fast twitch fibers. So why is that?

Well, this has to do with the characteristics of the fiber types or what you may even consider to be like the strengths and weaknesses of each muscle fiber type. So let's get into some of these amazing details starting with the slow twitch fibers. Slow twitch fibers are actually referred to as slow oxidative or type 1 fibers.

Slow oxidative is actually a pretty great name because these fibers contract with less velocity and they utilize oxidative phosphorylation which is an aerobic pathway utilizing oxygen within the mitochondria to generate ATP. So these muscle fibers have a ton of mitochondria and many tiny blood vessels called capillaries and by having a high number of capillaries. This allows a lot of oxygen, glucose and fatty acids to be delivered to these fibers. They also have a very high myoglobin content which is a protein similar to hemoglobin that binds and stores oxygen within these slow oxidative muscle fibers and myoglobin actually gives off a red color.

So the slow oxidative fibers are also sometimes referred to as red fibers whereas fast twitch fibers are sometimes referred to as white fibers. But this will also help us to understand the strengths of these slow oxidative or type 1 fibers. Because of their high mitochondria and oxygen content and their extensive blood supply, this makes these fibers extremely resistant to fatigue and so they are excellent for maintaining posture and aerobic endurance type activities such as distance running, cycling and swimming.

And so if you were to spend a lot of your exercise time doing endurance type activities or even lightweight resistance training, and you notice that your fitness in these areas improved this is in large part due to these muscle fibers adapting by increasing the size and number of mitochondria as well as the number of capillaries which translates to improved endurance but an adaptation that What you don't see as much with these fibers is a substantial increase in size or what is referred to as hypertrophy and so these muscle fibers have the smallest diameter of the fiber types which explains why if you see a marathon runner they typically aren't going to be huge from a muscular standpoint and this also reminds us what these fibers are not really built for and that again was they don't contract with as much velocity as the fast twitch fibers and therefore are not capable of generating as much force. And so now let's move on to the fast twitch fibers which are known as fast glycolytic or type 2x fibers. Fast glycolytic is also a great name because these fibers contract with the most velocity and they generate ATP very quickly through anaerobic glycolysis which is the breakdown of glucose in the absence of oxygen. And unlike the slow oxidative type 1 fibers, the fast glycolytic fibers have few capillaries and few mitochondria and also have less myoglobin. So they tend to have a pale to white appearance which is why they are sometimes referred to as the white fibers.

However, these fibers tend to be the largest in diameter and as we've already covered, contract with the most velocity and are capable of producing the most force. They also have an incredible capacity to store glycogen which is the storage form of glucose which makes sense because they primarily use glycolysis, the breakdown of glucose, to produce ATP. So when someone participates in exercises like heavy resistance training or explosive movements such as jumping and sprinting, these fibers will adapt by getting larger as well as increase their capacity to store glycogen.

But as you've probably already guessed, even though these fibers can contract with more velocity and produce more force, they can't sustain this for very long. Creating ATP through anaerobic glycolysis is very fast, but anaerobic glycolysis only produces two ATP molecules per molecule of glucose. which isn't a lot and won't last very long.

So these fast glycolytic fibers, yes, produce a lot of force, but their resistance to fatigue is much lower than the slow oxidative fibers. And just to give you some comparative numbers here, a slow oxidative fiber can take one molecule of glucose in the presence of oxygen and funnel its products into the mitochondria and make about 36 ATP. But again, these are trade-offs here.

Even though the slow oxidative fibers Make more ATP per molecule of glucose. It takes many more steps to do this and therefore is a much slower process of creating ATP. Now a lot of times people will refer to muscle fibers as just either fast twitch or slow twitch but as I hinted earlier, there's more to it than that and there's actually another really cool fiber type that is worth learning about and that is the fast oxidative or type 2a fibers and sometimes they're even referred to as fast oxidative glycolytic and it's Probably not going to surprise you that I'm going to reference the name of these fibers as also being named well because as the name implies, these fibers contract with more velocity than the slow oxidative fibers but not as fast as the fast glycolytic fibers. But what is also interesting is that these fibers primarily rely on aerobic metabolism for energy which makes them more resistant to fatigue than say like the fast glycolytic fibers. They can also switch to anaerobic metabolism when needed and utilize anaerobic glycolysis allowing them to produce ATP at a faster rate and enabling quicker and more powerful contractions than again the slow oxidative fibers.

And this is sometimes why they're referred to as fast oxidative glycolytic rather than just fast oxidative because they can do a little bit of both. You could kind of think of them as the intermediate or the hybrid fibers with the ability to do a bit of what each of the other fibers can do. Another characteristic of the fast oxidative fibers is that they have a lighter pink color that comes from a lower myoglobin content compared to the slow oxidative fibers. But they still have more myoglobin and therefore a better oxygen supply than the fast glycolytic fibers.

The fast oxidative fibers also have a moderate number of mitochondria and glycogen stores and all of these characteristics give them an advantage for sustained but more moderately intense endurance activities. such as running or swimming and even though they don't generate as much velocity and force as the fast glycolytic fibers they are more resistant to fatigue making them ideal for activities that require both endurance and a moderate level of speed Now what is also interesting is how your body decides which fiber type to use and it pretty much depends on the task. In general, if you're doing something light like maintaining posture or lifting a lighter weight, your slow oxidative fibers are the first to be recruited and if you need a little bit more force then your fast oxidative fibers are activated but when maximum effort is required, say you're sprinting or lifting a heavy weight, your fast glycolytic fibers are then called into action. And I actually have another video where we go into motor unit recruitment, where we discuss recruiting muscle fibers in even more detail. So I'll link that at the end of this video.

So we kind of went into a lot of information there. So Jeffrey and I think that we should finish up by summarizing what we've discussed. And then more importantly, apply it to your own health and fitness. And I think this chart really helps us to summarize the characteristics and differences of each fiber type. So we've got our slow oxidative or type one fibers.

They have a large amount of myoglobin, many mitochondria and capillaries. and because of the large amount of myoglobin we have that red color. They have this high capacity to generate a lot of ATP through aerobic respiration but again through aerobic respiration that takes more steps and therefore takes more time and so their rate of ATP use is slower, their contraction velocity is slow, however they have that extremely high resistance to fatigue and so these muscle fibers are great at maintaining posture and for aerobic endurance type activities.

Then we've got our fast oxidative sometimes referred to as fast oxidative glycolytic or type 2a fibers. These are our hybrids. They can do a little bit of both or a little bit of everything and so we have this intermediate amount of myoglobin.

They still have a good amount of mitochondria and capillaries but because of that intermediate amount of myoglobin they start to have this pink color. Now as far as generating ATP in intermediate capacity by both aerobic respiration and anaerobic glycolysis. And because they can do anaerobic glycolysis, they can have a fast rate of ATP use, but an intermediate contraction velocity and an intermediate level of resistance to fatigue. Now, these muscle fibers are great for like moderate to high intensity aerobic endurance.

So maybe if you're jogging at a more slow pace and then you started picking up the pace, you'd start to fire into some of these fibers. Think also longer sprints, maybe like 200 to 400 meters. And then intermediate resistance training would also start to fire into these fibers as well. And then we have our fast of the fast, the fast glycolytic or type 2x fibers. They have a small amount of myoglobin, few mitochondria, and few capillaries.

And because of the small amount of myoglobin, they have that white to pale color. Now, they have a low capacity to generate a lot of ATP. However, they can make the ATP really quickly.

The small amount that they do make, they can make it really quickly through that anaerobic glycolysis. And so their rate of ATP use is fast. Their contraction velocity is going to be fast.

And their resistance to fatigue, however, is going to be much less than the other fiber types, especially much less than the slow oxidative fibers. But they're great, sorry Jeffrey, I'm getting in your way here, for rapid intense movements of short duration. Think like full-fledged sprints, like a 100 meter dash, and then also heavier resistance training. Now here is what is very interesting about all this.

Yes, we do have a genetic predisposition to have certain proportions of muscle fiber types. And when you train in a certain way, you will create adaptations in the fibers that you already have. So if you do lower intensity endurance type activities, you'll see adaptations in your slow oxidative fibers. If you start to increase the intensity and do more moderate endurance type activities and even some moderate loads of weight training, you'll start to get adaptations in your fast oxidative fibers. And then of course, if you do even higher intensity weight training with even higher loads.

and or explosive exercises like sprinting and jumping you'll start to see adaptations in your fast glycolytic fibers however your muscle fiber types are not completely set in stone and while you cannot change your genetic makeup the types of exercises that you participate in the most can influence the conversion of one muscle fiber type into another now this obviously will take time and consistency but if you were to spend most of your time doing sprinting, jumping, Olympic lifting, you'd see some of these fibers on this end start to convert into more of the fast glycolytic type. And on the flip side, if you spend more time doing steady state long duration endurance activities like distance running, you'd start to see fibers on this end converting more towards those slow oxidative type. And there have been some fascinating studies with monozygotic twins, which is a fancy pants way of saying identical twins. But one particular study I'm thinking of. took biopsies of the quad muscles from each twin and the one twin that had participated in endurance training for years and years Nearly 90% of the quad fibers were more of the slow twitch variety while the twin that had not participated in long-term endurance was closer to 50-50 fast twitch to slow twitch.

So it really helps to show that yes, genetics does predispose you to be better at certain types of exercises in sports but you can stimulate some incredible adaptations with consistent training in types of exercises and activities that you may enjoy more than others. As some of you may know, we launched the Institute of Human Anatomy back in 2012, and it's been an amazing journey every step of the way. We've taught millions of people through our videos and are looking forward to educating even more about the wonders of the human body.

I'm so personally grateful for every comment, share, and view from our audience, and the worldwide support is truly mind-blowing. We would not be able to keep creating if it weren't for all of you. Back in July, you may have also known that we launched an anatomy app. It's been an incredible few months of testing, and taking feedback from our users inside the community.

So now I'm thrilled to announce the relaunch of the Institute of Human Anatomy membership community app with new pricing and new features. We believe we've created something truly special. In this revamped app, you'll find monthly live sessions where we dive deep into different body systems, access to me 24 7 with our new AI assistant to answer all of your burning anatomy questions anytime over 140 comprehensive study guides and quizzes. Monthly Ask Me Anything livestreams where I'll get to answer your burning questions in real time.

Special interest groups designed for healthcare professionals, fitness enthusiasts, students, educators and just regular old anatomy nerds. And lastly, a structured learning path to keep you engaged and learning. So whether you're looking to enhance your professional skills, ace your anatomy class, chat with anatomy nerds like you, or simply satisfy your curiosity about the human body, this app is definitely for you. So join us today in our incredible community by checking out the link in the description below.

We have new pricing that you don't want to miss. Thank you again for all of your support. I'm so excited for you to check out our community where there's no limit to this anatomical awesomeness.

Transcript for:Understanding Muscle Fiber Types and Training

Transcript for:
Understanding Muscle Fiber Types and Training