All you need to Learn About Muscle Fiber Types

 

Muscle Fibers Explained Muscle Contraction and Muscle Fiber Anatomy

Video taken from the channel: PictureFit


 

Muscle Basics: What Athletes Need to Know About the Muscular System

Video taken from the channel: Sportology


 

Muscle Fiber TYPES Explained: Part 1

Video taken from the channel: Shredded Sports Science


 

Type 1 and type 2 muscle fibers | Muscular-skeletal system physiology | NCLEX-RN | Khan Academy

Video taken from the channel: khanacademymedicine


 

Muscle Fiber Testing

Video taken from the channel: Mike Lipowski


 

Myology | Type I Muscle Fibers

Video taken from the channel: Ninja Nerd Lectures


 

Myology: Type II Muscle Fibers | Type IIa & IIx

Video taken from the channel: Ninja Nerd Lectures


There are two primary muscle fiber types: Type I or Slow-Twitch Muscle Fibers These muscle fibers are endurance-focused. However, within the two primary muscle fiber types are subtypes, including type I, Ic, IIc, IIac, IIa, IIax and IIx. While you can’t magically turn a type I muscle fiber into a type II fiber (and vice versa), you can change a muscle fiber’s subtype through training. Today, we discuss the different types of muscle fibers in the body along with everything else you need to know about muscle fiber types. Muscle Fibers 101 Within a single muscle (such as your biceps), there are thousands of individual muscle fibers composed of both fast and slow twitch muscle fibers.

Now, the percentage of slow vs fast twitch muscle fibers within a muscle depends on several factors. Color of type I fibers (which contain more blood-carrying myoglobin molecules). 30s The age at which most of us start to see a drop-off in the number of type IIX and type IIA muscle fibers. Type I decrease a little more slowly.

White Color of type II fibers, which are noticeably lighter in color than type I. It’s generally accepted that all the muscle fiber bundles can be broken down into one of two categories: slow-twitch (aka type I) and fast-twitch (aka type II). Understand that muscle fibers exist on a super micro level.

For instance, you couldn’t look at a biceps muscle and say, that’s a. Nick Nilsson’s quick tips on finding your muscle fiber type, including the slow twice and fast twitch. T here are two main types of fibers in your muscles. Slow Twitch: These are also known as Type I muscle fibers.

They are responsible for long-duration, low intensity activity such as walking or any other aerobic activity. Sounds complicated but all you really need to know is that muscle contractions come from thousands of smaller contractions controlled by these fibers. These muscle fibers are not all born equal though and can be broadly divided into type 1 (slow twitch), type.

Before we dive into the answer, there are a few things you need to know about fiber types. First, researchers generally classify human muscle fibers as Type I (slow twitch), Type IIa (fast twitch. Type I muscle fibers require more oxygen to produce energy than type II muscle fibers, so they are red.

Their counterparts, type II muscle fibers, which are. Here’s a few things you can do right now to determine your muscle fiber type: Fast Twitch. Better at sprinting as opposed to long distance running; explosive power; Vertical jump higher than 23 inches; Less than 7 reps on 80% of your 1 rep max. Longer rest periods between sets; Slow Twitch.

Better at marathons or long distance running.

List of related literature:

The connective tissues of a muscle include a thin endomysium around each muscle fiber, a thicker perimysium that binds fibers into bundles called fascicles, and an epimysium that surrounds the entire muscle.

“Human Anatomy' 2007 Ed.2007 Edition” by Kenneth S. Saladin
from Human Anatomy’ 2007 Ed.2007 Edition
by Kenneth S. Saladin
TPB, 2008

There are several bundles of fibers inside the muscle which are covered by thin connective tissue layers, the perimysium, and each individual fiber is wrapped by thin collagen, the endomysium (see Figure 28.1).

“Handbook of Food Science, Technology, and Engineering 4 Volume Set” by Y. H. Hui, Frank Sherkat
from Handbook of Food Science, Technology, and Engineering 4 Volume Set
by Y. H. Hui, Frank Sherkat
CRC Press, 2005

The surface of the muscle fiber consists of three layers: an outer network of collagen fibrils, a middle basement lamina composed of type IV collagen and proteoglycans, and an inner plasma membrane called the sarcolemma.

“Food Chemistry, Third Edition” by Owen R. Fennema
from Food Chemistry, Third Edition
by Owen R. Fennema
Taylor & Francis, 1996

In jaw muscles, light-stained type I fibers predominate that are associated with long contraction times (slow twitch), high aerobic capability, and resistance to fatigue, whereas dark-stained anaerobic fasttwitch type II fibers predominate in limb muscles (Figure 14-1).

“Functional Occlusion in Restorative Dentistry and Prosthodontics E-Book” by Iven Klineberg, Steven Eckert
from Functional Occlusion in Restorative Dentistry and Prosthodontics E-Book
by Iven Klineberg, Steven Eckert
Elsevier Health Sciences, 2015

The exact functions of the variety of specific muscle fiber types are unknown, and it is likely that various fibers have overlapping functions.27 Within extraocular muscle tissue are neuromuscular spindles that are concentrated at the muscle–tendon junction.

“Pediatric Ophthalmology and Strabismus” by Kenneth W. Wright, MD, Yi Ning J. Strube
from Pediatric Ophthalmology and Strabismus
by Kenneth W. Wright, MD, Yi Ning J. Strube
OUP USA, 2012

On the basis of their location, structure and function, there are three types of muscle fibres: skeletal, smooth and cardiac.

“NEET 2020 Biology Guide 7th Edition” by Disha Experts
from NEET 2020 Biology Guide 7th Edition
by Disha Experts
Disha Publications,

Muscle tissue contains two types of fibers that are responsible for contraction: thin and thick filaments.

“Porth's Pathophysiology: Concepts of Altered Health States” by Sheila Grossman
from Porth’s Pathophysiology: Concepts of Altered Health States
by Sheila Grossman
Wolters Kluwer Health, 2013

Skeletal muscles contain two basic fiber types, each with its own contractile and metabolic profile.

“Nutrient Timing: The Future of Sports Nutrition” by John Ivy, Robert Portman
from Nutrient Timing: The Future of Sports Nutrition
by John Ivy, Robert Portman
Basic Health Publications, 2004

Mammalian skeletal muscle comprises different fiber types that differ in contractile properties, metabolic parameters, and expression of distinctive myosin isoforms [4].

“Muscle Gene Therapy” by Dongsheng Duan, Jerry R. Mendell
from Muscle Gene Therapy
by Dongsheng Duan, Jerry R. Mendell
Springer International Publishing, 2019

There are three types of specialised contractile cells, also known as fibres: skeletal muscle, smooth muscle and cardiac muscle.

“Ross & Wilson Anatomy and Physiology in Health and Illness E-Book” by Anne Waugh, Allison Grant
from Ross & Wilson Anatomy and Physiology in Health and Illness E-Book
by Anne Waugh, Allison Grant
Elsevier Health Sciences, 2010

Alexia Lewis RD

Registered Dietitian Nutritionist and Certified Heath Coach who believes life is better with science, humor, and beautiful, delicious, healthy food.

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97 comments

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  • Thoroughly explained thank you!!! Just wondering, would you be able to explain why fast-twitch fibers have greater calcium-pumping capacity? Came across this from another source and would like to understand why that is. Thanks!

  • Your videos are really good.
    I have a questionif size of II x is larger than II a so how can increase in myofibril and mitochondria change II a into II x

  • What would be the type of trainings for increasing oxygen capacity of the type 2X muscle fibers? Endurance, HIIT, Lactate Threshold, or power lifting?

  • thank you for the awsome explanation, going through strength and conditions class this really helped. if possible cover certain topics related to strength and conditions your way of explanation is great!

  • Hi! I’d like to show your great videos in my Anatomy Class, BUT my school district blocks your video because you categorize your videos as “entertainment” Could you please categorize them as “educational”?
    Thanks!

  • Wait so every skeletal muscle has some of each fiber type in it? What does the distribution look like?
    So my bicep would have all three but more of the type II-x????

  • Thank you so MUCH.

    I’m a medical student here and all your contributions are just way SO MUCH.
    I’d like to take a brief moment to thank for all the things you’ve done.
    I’ve learnt the whole biochemistry from your videos and so much more. You’re a savior, man!

    I decided to become a patreon, you deserved it.

  • Very well explained brother but 7:40 the muscle though stores glycogen cannot utilize it because it lacks glucose 6 phosphatase.. so has to travel back to liver to be converted to glucose..

  • Type IIa does not have the largest diameter. Its the IIx.

    Type IIa is intermediate in diameter. You mixed does up.

    Still a great video tho. Thanks

  • Great video. Would love some details about differences in calcium-buffering proteins (e.g. Parvalbumin) between Type I and II fibers, and how this influences contractility.

  • Another huge THANK YOU for this amazingly helpful video you guys!!! Getting my ISSA certification and its grea to get all these details. Question about BCAA’s and how they work via powder supplements. Is it accurate to think about BCAAs assisting or facilitating the more limited ATP production in type 2x and 2a fibers during resistance training?

  • Yeah I really liked it. If your type one muscle (weak long endurance or posture muscle) fails, what would be the cause of that? You can lift a heavy thing but a teacup is suddenly heavy? Any guess? Similar what if standing up ((posture muscle) is extremely hard to do, what could be the cause of that? Thanks.

  • If the type IIa fibers are the biggest, would it make sense to target these fibers for bodybuilding? And what rep range would induce hypertrophy in these fibers?

  • Hi there! I’m workingon my personal trainer certification and I love how you explain, it’s being really helpful. Just the same comment than the other guy, my book says the type IIx are the largest and fastest. And type IIa last up to 3 minutes (not 30) and force production between I and IIx. My book is ACE Essentials of Excercise Science for Fitness Professionals.

  • Good day. I hope i am not over stepping my boundaries, but i would like to know where you got the information on the type 2x fibers being of humans and type 2b fibers being of animals. I am just a bit confused and most studies i have looked at only has mice as the subjects.

  • god bless u n ur family with good health and peace..will definitely contribute somethin soo through patreon when i start earning as soon as possible…:)…

  • Awesome. Ive gotten back into working out, but this time I’ve decided to research as much as I could with the exercises and the nutrition and also this physiological side of muscle development. On another channel, I learned about the difference between the 2 kinds of muscle fiber and the 80% test, and now a more informative video on the test itself. Thank you, you broke it down very well, and it makes sense to me. I appreciate ya man thank you.

  • well i did it with pull ups
    first set like 9 or 10 and my arms did not responds in the second set at the point I only did 2 reps my back is ok but my arms well my biceps are beaten

  • Took a DNA test and I have type II x. Unfortunately it hasn’t appeared to make me a fast sprinter or a good lifter of heavy weights. That said, my muscles definitely fatigue very quickly! So it’s a lose/lose for me I guess.

  • How in the world slow twitch fibers can be engaged in the work that lasts 50 seconds till failure? They are designed for endurance work, not 10-20 rep sets in the gym. Here both sets are done with FT and the results only show how trained they are.

  • hi sir mike! after watching the video i done the exercise
    chest [push-up] 10 reps per set
    1st set = 22 sec
    2nd set = 21 sec
    3rd set = 19 sec
    i think that is a Fast Twitch or Type IIa Fibers did i get it right sir?.
    please correct me if i am wrong…. Thank you for the video

  • Great way to test! Would like to see if there was ever a study done on this using a very similar method and logging all the data so we can see distribution curves of muscle fibre types in different groups of muscles. I’m guessing the normal distribution would be evenly mixed fast and slow twitch for most muscle groups, but it would be interesting to see which muscle groups tend toward one end of the spectrum or the other.

  • Hi Mike, i just spent the last few days fibre testing every muscle group. On the 2nd set I can usually only do half as many reps, with the exceptions being abs and calfs. I doubt that I’m 90% FT otherwise I’d be much bigger than I am after years at the gym. Could overall stamina be a factor in this experiment? Could it be that I can only do half as many reps on the second set, not because of the strain on the muscle fiber itself, but just because I’m overall winded? How does systemic recovery ability affect the tracking of specific muscle performance?

  • I like this idea. But I think it certainly needs some empirical validity just like the Henneman test. I would caution though, because as you rightly point out FT fibres take long time to recover, but this may not actually be the motor neurons, because they neuron itself can recover pretty quick.

  • Fibers fibers and more fibers!! I love it!! I just posted a smoothie recipe on my page Chancyfit https://www.youtube.com/channel/UCVJabLlAYojGBePsYAPieUQ let’s grow and get healthy together. Subscribe to my channel Chancyfit����

  • Fibers fibers and more fibers!! I love it!! I just posted a smoothie recipe on my page Chancyfit https://www.youtube.com/channel/UCVJabLlAYojGBePsYAPieUQ let’s grow and get healthy together. Subscribe to my channel Chancyfit����

  • I have a question
    A teacher of mine once said that as we get older our muscles are slowly becoming “white” like “tendons” (not literally)
    Did he mean that when we are young we have more type 1 mucles fibers and as we get older they transform into type 2? But that does not make any sense cuz marathon runners that need endurance muscles are always older people…..i am confused can anybody explain me what happens to the mucle fibers as we get older?
    And if age plays a role in the concentration of type 1 muscle fibers?

  • Very interesting and relevant content, brilliantly edited and presented by James. Anxiously looking forward for the release of part 2.

  • There is actually a type 2 muscle fiber that is red because it has myoglobin (like hemoglobin, it stores oxygen), and it actually aerobic. the other type 2 muscle fiber uses glycogen, that is why it is white and is anaerobic. 

  • Thanks for your video, but I am confused.
    I just found two explanations where they say that “Type 2” are actually legs, back and bigger muscles, the ones you actually categorize as “Type 1” in your video (you say that Type 2 are your finger muscles). Type 2 seem to be the red ones according to two random searches on the internet (white in your video).

    Can you please clarify?

    Source here:
    https://buildingmuscle.org/muscle-fibers-explained-type-1-and-type-2/
    https://www.quora.com/What-are-the-examples-of-type-I-and-type-II-muscle-fibres

    Both the above state the opposite of what you are saying. I am confused as your video seem to be quite deep.

  • You can use two types of muscle fibers which are fast twitch and slow twitch. In order to grow muscle effectively, using two muscle fibers might help you to acheive your goal which is being in a shape. You might want to add explosive movements and resistance training in your program.

  • Taking MCAT on Saturday so I’m justing brushing up on high yield stuff that is a little fuzzy, and the type 1 and m1tochondi1a analogy is golden. I’ll never forget now!

  • Type I:
    -Slow
    -Oxidative

    Type II:
    -IIa:
    -Fast
    -Oxidative
    -Glycolytic
    -Higher Production
    -Fatigue Resistant

    -IIb:
    Fast
    -Glycolytic
    -Fatigue Quickly
    -Strong

  • thank you for your amazing explanation, but according to Lauralee sherwood for human physiology, it is saying that muscle fibers type two especially (fast-oxidative) are red in nature, the only type of fibers that is not red is fast-glycolytic which is one of types two muscle fibers.

  • I wish in muscle fibers Type 2 a & b differentiation should have been mentioned with more explanation including type of ATPase activity and oxidative capacity which explains better in understanding of the muscle fibers.

  • thanks. but how do u know which one is dominant in your body?
    when I compare myself whith someone of the same waight and age group and pretty much the same fitness I am usually stronger but it does not last or my muscles and whole body look bigger than them.
    please help me find out which type mine is thx.

  • I can twitch every muscle in my body at will and make it twitch rapidly. They get tired very easily. Non of my muscles have endurance but a lot of force output. I have at least a 90/10 ratio leaning towards fast twitch. Fast twitch definitely have more power but less endurance

  • Great video. Very informative and its only part one. I did the 80% test year’s ago. I’m going to try it again. Can’t wait for part two. Great timing with this video James.

  • Great explanation! I learned it as type 1 = slow oxidative and type 2 = fast glycolitic, so we didn’t have the problem of the useless names!

  • 6:25 isn’t this chart circular-logic?
    e.g. (first row of the table) if you can lift 80% of your 1RM in 1 rep, wouldn’t that mean that you over-estimated your 1RM by 20%? How is it 80% of 1RM if you can only perform 1 rep of it?
    Also if you get your 1RM through estimation, and test yourself according to the chart to find your range of reps for your 80% 1RM, then input these results into the same formula you used to get your 1RM you will get skewed 1RM.
    I know this chart is only meant as a rule of thumb, but it makes no sense even at that.

  • I have a feeling James is sneaky strong. Maybe some experience in BJJ or combo (MMA) or even wrestling (whats you ring name and finishing move?)

  • With all do respect, I must disagree most strongly. There are only 4 different types of muscle fibers Slow Oxidative, Fast Oxidative, Fast Oxidative-Glycolitic and Fast Glycolitic. One can engage in a set protocol that isn’t so light as to permit the Slow Oxidative fibers to recuperate and never call upon the higher order fibers nor so heavy that the Fast Glycolitic are immediately called upon and thus exhaust before the lower order fibers are recruited, With a set protocol such as that, which the work of Dr. Doug McGuff has show is a set that exhausts the muscles involved within 45-90 seconds, then we can, in an orderly and sequential manner, exhaust all the fibers in a muscle starting with the SO, then the FO, then the FOG and finally the FG. Using a protocol such as this, there is no need to use various exercises or training protocols to “stimulate” all the muscle fibers, because all the muscle fibers involved in a movement will have been stimulated in that one exercise. Nor are multiple sets required, because again all the muscles involved in a muscle being worked will have been stimulated. This assumes, of course, that equipment that varies the resistance applied to the working muscle throughout the range of movement is being used. Thus, this type of muscular stimulation and orderly, sequential recruitment cannot be achieved with free weight movements is the variation is gravity dependent. This set protocol requires, rather, that machines properly designed for the exercise are bg used which include, but are not limited to, Nautiilus, MedX, Cybex, Hammer Strength and/or LifeFitness.

  • This video is great James! Would love to see some more lecture style things (although the shutdown vids are a lot of fun I must admit).

  • Type 1 are slow twitch muscle fiber, and they are red because of the myoglobin, which is like hemoglobin, therefore oxidative, using oxygen(aerobic=with oxygen) Type 2 are fast twitch, and are white, because they don’t need oxygen to use ATP, and are called anaerobic.

  • whoah whoah whoah, 80% 1RM test and people are getting 12+ reps? how the fuck does that work, so someone who gets 3 reps is type II dominants but someone who gets 18+ reps WITH 80% of a 1rm is type I dominant? you see the problem here? the type II are bigger and stronger yet get out performed on weights they evolved to handle? if its 80% of a 1RM how can anyone get more than a few reps. that test is complete and utter bullshit

  • Great vid! I was wondering if you could direct me to a resource so I can overhaul my program? I’m running PPL, but I’m static on volume and intensity between push and pull A, and push and pull B. Thinking I want to switch to running high volume on one session, and high intensity on the other. I’ve never trained this way, so I need to do some research, but I’m not sure where to look for quality info. Thanks.

  • Simple 2-step test to determine muscle fiber type.

    #fasttwitchmusclefibers   #slowtwitchmusclefibers   #bodybuilding   #fitnesstips   #exercisetips  

  • Hey James, recently discovered your channel and love your videos. They are insanely informative, thanks!
    Just, would it be possible for you to place the microphone directly (straight) in front of you? It’s a bit distracting with headphones:-)

  • Christ… can you tell us WHAT muscles are type 1 and type 2?

    Example:

    Are calves type 1? Are abs type 1? Pecs? Forearms?

    Why cant people just do a video that gets to the point instead of flooding youtube with “This is how type 1 fibres function” videos?

  • Very useful info James! Thanks for sharing.
    You are way too humble for your level of knowledge.
    I am looking forward for the next part!

  • Very nice video James!! It’s the basics but someone has to teach them!!!
    I am under the belief that young kids (13-21) can change their muscle fiber’s type much easier than adults, depending on what their training is focused on. Do you have any study that supports this, or am i totally wrong?

  • Can you make a video on how to properly be in a caloric deficit and how to find out how much deficit each individual should ne on? Thanks!

  • Great video again. Looking forward to part 2.
    I had noticed that my calves responded far greater to the elliptical on an intense difficulty. But, it was conjecture on my part until now. I’ll be sharing this info, a lot of people at the gym hit legs harder, and more frequently than I do, but seem to struggle building calves.

  • Hey, I don’t know if this comment will reach you or not. I wanna know, if can get my hypertrophy by fast twitch fibres or not. I wanna be big (not too big like Rich Piana), but also have explosive strength, endurance and speed. I am not hoping to achieve Speed like Usain Bolt or Size like Arnold or Power like Mike Tyson. I just want an overall balanced body. Please do address this question in your video.
    Thanks.

  • I have been all three of the types mentioned above, at an earlier period I was able to lift heavier weights & for some 10 years I ceased all forms of exercises & loss both strength & stamina but now I can do endurance running & HITT cardio at high reps. Sir, you are correct to say muscle fibers can adapt to different types of training & activities with time…..

  • Very informative as always! I knew about type I and II but didn’t realize there was a 2A and 2X. I need to do more for the 2x in my workouts.

  • I also just saw a video saying red fibers are the fast ones! Please answer, difficult to decide who to trust even though I want to trust the K Academy!

  • I’ve tried the CT test for muscle fiber dominance and it seems i’m extremely fast twitch dominant and indeed,I can move pretty heavy weight easily but not for too long,as my muscle give up fairly quickly…so I guess these are type 2x?And as always awesome video!

  • First! Muscle Fibers can change type but scientists don’t know how much, how long to train etc. Science has stronger methods of analysis and better research now. If you don’t understand the difference between histochemistry and Electrophoresis for muscle fiber analysis then please look into it. Thank you.

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  • When it comes to eating healthy, you have to try not to fall victim to modern day fad diets. Extreme diets undoubtedly are a risk for your health, especially ones that seriously restrict your daily nutritionary intake. While they may generate rapid loss of weight, these kinds of diet plans will never be a long-term solution for your waistline. It is best to look up Custokebon Secrets on google search engine as it is not just another fad diet where you starve yourself.

  • Guys. lost crazy amounts of weight doesn’t need to be hard (I used to think it did). I’ll give you some advice now. Get a popular lose weight diet plan called Custokebon Secrets (do a search on google). Thanks to it I’ve lost a ton of fat. I probably should not even be speaking about it cause I don’t really want a lot of other guys out there running exactly the same game but whatever. I’m just simply in a excellent mood right now so I will share the wealth lol.

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  • Hey there… I love your videos.. you make them so interesting and easy to learn… U are such an inspiration… And inspired by I also tried to make study interesting by making videos on 3d digitals…. I am a surgeon and this way I can memorise things easier

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  • Hi there, I want to know if Fenoboci Diet Plan, will work for me? I notice many people keep on speaking about this popular lose weight method.

  • Very informative video! Best part is, I love how you broke everything down in 3 minutes! Great job! Defiantly found this to be helpful!

  • 2:58 (meat) protein is bull shit! I’m
    On a 100% whole plant based diet. And I’m 5’10, 185lbs!! I’m ripped! And I get results clearly from working out. Humans don’t need meat or dairy simple as that.

  • You should include a component on the importance of increased neural activation and/or muscle fiber synchronization to increase strength. Research shows many people increase strength without adding new muscle mass, since this is more efficient for the body. Also, if you’re going to show protein, data that shows people, especially Americans need more protein to grow strength, especially at a recreational level (my guess is they don’t and many Americans waste a lot of money on protein supplements that they don’t need). Nice video overall.

  • Hey guys! Love the videos, I was wondering if you were planning on a more advanced video about these things especially with muscles and bones just because this video was great for basics and I’d love to hear you guys explain the more advanced side of things. Keep it up:)

  • People often say that if you want to grow muscles which have mostly type I or type IIa fiber, you need to train them in a low weight high reps so they grow more. It isnt correct, is it? Do I get it right: when it comes to hipertrophy, muscle fibers don’t play role in workout plan. Right?

  • Does any of this matter if in a calorie deficit if you can’t build muscle during this time? Can you still change hybrid fibers to type 2 during this time?

  • Wait, if the recruitment order is type 1, 2a, 2x. Then is that true for exercises like sprinting and powerlifting where type 2x should dominate? Pls answer fast.

  • So do all muscle fibers exist in all parts of ur body? For example on the bicep does it mainly consist of one muscle fiber, or can all three be developed in that area?

  • Apparently 23andMe told me that I’m mostly on the slow twitch muscle spectrum. On the other hand I’m doing great at sprinting, weight lifting and I suck on endurance exercises. Wtf?

    I’m also too bulky by nature to be considered a marathon runner

  • great video re: muscles plus check this video out: https://www.youtube.com/watch?v=-N-CBQIVGao How Much Protein Is In Skeletal Muscle? The Structure and Composition

  • Excellent video, I’ve found this is one of the most overlooked and misunderstood principles for many people looking to gain muscle mass.

  • i am am 8th grader and i do a lot of track and field. I’m on the relay team and very fast at my 100 sprints but i’m also long distance and get 5 minute miles and 18-20 minute 5ks…. this is so confusing to me because if i’m good at all of them then what type of muscle fibers do i mostly have??

  • Pretty descent rip off from minute physics, as in, no added style, just less tight visually, and slightly less knowledgeable on the topic. But most people won’t know this is shameless hack, let alone be able to see its limitations, so: well done!

  • Yep I got Fast twitch, I train Kickboxing and when we do speed punches my muscles don’t last long,but I have a lot of speed and incredible power for my hight I’m 5 foot 5 and weigh about 150 pounds, 68KG.

  • Sir How Much Tension/Force Is Required To Break A Single Strand Of muscle Fibre?
    Would Be A Big Help If You Could Suggest In Units / Mathematical Formula

  • I’m not very fast and cant gain muscle very fast either. My friend on the other hand is extremely fast and can gain muscle easily.

  • Hey, I have a twin sister, we’re on “different levels” she’s good at long distance but I’m only good at sprinting really fast in a short amount of time (which is useful for me in football). But, I find this kinda cool, because she thinks twins are always supposed to be indentical. But how did this happen?

  • I play a lot of basketball and row at the gym so I think more Type II muscles since I only do short 1 minute bursts of rowing and a lot of short burst of movement for basketball

  • i think i might train type 2 a fibres the most, then also put effort into the type 2 x ones.
    i was already born with dominant type 1’s

  • You mention type IIa skeletal muscle fibres being bigger than type IIx in humans, could you provide a source for that? I’ve so far read the opposite and would like to know more please.

  • Hey, love your channel and hope it goes far. Any chance you could label your sources though? Like Kurtzgesat does. You guys should collab. I think you’d both win.

  • Slow twitch muscle doesnt grow or show like fast twitch… So regardless, One should always strive to build more fast twitch for that is what grows and makes you muscular..

  • Mostly power focused. Always looking for speed, I guess that I train more my fast twitch fibers. Mixed strength/hypertrophy training

  • I think I have a mixture of both type 2s to a high degree. I plateau very easily so I can’t just stick with one type or another. I guess if I do pyramid sets I’d prosper more than straight sets.

  • Well if u go to deep cardiac and smooth muscles are involuntary but both do not work on their own.
    Only cardiac muscles are autonomous (can regulate themselves) and smooth muscles are under the control of the ANS

  • Since my purpose is to have stamina & strength endurance, I’m training for type I and type IIa mostly, thru exercises such as long distance running ���� and sometimes hiking. Now I’m thinking that somehow I have to train for type IIx as well, so that aesthetically, I’d look better while having adequate strength as well