Being a certified fitness trainer, I must confess that I keep my knowledge of human anatomy up to date from this channel. Thank you for these valuable videos.
I been lifting weights (mostly heavy) for about 15 years, over a year ago I started with mma training, it’s amazing to see how the body adapts itself, mma is a mix of training, you need endurance, you need to be strong and fast so basically you train all the muscle fibers, energy systems and trying to find best balance that would suit the needs of that sport, body is an amazing machine. Love your content!
@@breadman5048 thats skeletal endurance im talking about pure muscular endurance like can you believe pro cyclists use over 5000 calories per ride and they intake that during the ride aswell? so their muscles have hugeeeeeeeeee aerobic efficiency
As a sprint athlete who used to be forced to do a bunch of aerobic training, I LOVE this topic! It’s been one of my favorites to talk about to my peers for years! So happy to see yall made a video on it!
This was really cool, I did track in high school, I was not a good sprinter, and I did not have the endurance of the cross country kids. But I crushed people in the 800. Learning about this third Type IIA fiber explains a lot to me.
Excellent, I studied these concepts already but it was a sisyphean task to remember it, but the visualization and the practical relations just might do it! Thank you!
I had an honors class where we had to pick a topic and I chose to do mine over the different types of muscle fibers! Over 20 pages and over 30 sources later and it’s done! Love how interesting this stuff is!
Thanks for all your hard work. I'm not a medical pro, but I love your channel because it gives good info on fitness and health for regular folks like me. I also get useful tips from Dr. Aaron Horschig's Squat University channel. Much love and best wishes.
I m a male type 2 predominant. I struggle to keep up with endurance training. For this matter, my FTP on the cycling power/watts calculation is just “good”. Even though I have been training for 3 years I hardly touched 3/watts kg. Now when it comes to repeating sprinting uphill or all out 2 minutes max power output, although very exhausting, I feel great about it and perform well, actually better than endurance alone.
just ride a lot of zone 2, and I mean a lot - ramp up to 5-8 hour rides, 20 hours+ per week. If you do that consistently for a season, you WILL see improvements, even if you don't do any more intensive rides.
I have been a runner for many years now, running at least 6km’s a day, but with the onset of menopause I find that running is not helping anymore so I have started strength training . It will be interesting to see how my body adapts to these changes
You need transdermal bio identical hrt ( estradiol, progesterone and testosterone) when no medical contra indication as can be estradiol sensitive breastcancer. Dr. Louise Newson UK is giving awsome explanations. Check her out.
wonder how much the genetic fast/slow twitch fibre composition in the vocal chords(thyroarythenoid) affects singing ability? presumably those with more fast twitch have more powerful voices and thicker easier to adduct vocal chords than those with abundance of slow twitch?
I always knew tbis doing sport n things that use all muscle fiber types. Now I know the science behind it all.I know I do best sprinting.Becauae I was born a sprinter. I boxed,sprinted,and did long distance training. I definitely understand the differences.
Arnold Schwarzenegger had genetically small and weak calve muscles and early pictures show him up to his knees in water. However, after being ribbed by other bodybuilders he put in an all out effort into his calve training until they became his best body part. Great video.
I'm hoping he will address musicians; pianists in particular (because I am one). Also, there is a difference in the neurological development between string players and other musicians.
There very well may be, or possibly absolutely is, a difference in the neurological development of different musicians, since their instruments require different physical skills (I.e. wind versus piano, etc)
the marathoner , cuz more capillaries and slow fibers and more fat, hes tastier😂🎉😂🎉...game hunters like a 1 head bullet shot, cuz they say if you injure him so he lives a few more seconds the adrenalin spoils the meat, its not tastey meat
Some folk built like this, some folk are built like that. But the way I am built, a- don’t you call me fat because I am built for comfort, I ain’t built for speed. But I got everything all the good girls need. 😂🎸✌️
It's a big reason I do both heavy lifts as we all higher rep days. Building both IIa and IIx help for long term functional strength. Yes, I'm a total nerd in the gym
13:40 What was that twin study referenced here? I'm wondering if the difference found was in volume of muscle fiber type or in the quantity of fibers, as you suggested. My understanding from reading up on current muscle tissue literature is that while you can certainly encourage the growth of one fiber type relative to another, no one has definitively shown muscle fibers to change types *in humans*. Just because we see it in other related organisms like mice is not a guarantee that it happens in humans.
But what are the effects of those transitioning fibers on human body? How does that influence a human body in it's lifetime? What should be aimed for? Are fast twitch better?
What type of fibers am I building doing varying intensity, low-mid-low weight, long duration, full range of motion, varying speed, weighted shadowboxing and movement drills? I use 2 between 10-15-25-30-40lbs weights counting up and down and am obviously slower the higher the weight. The workout includes explosive footwork, squats, lunges, and every kind of arm workout. I go for well over an hour usually and sometimes for +4 hours with hot-cold-hot showers in between.
Think about any sprint or explosive effort where you felt dizzy and wanted to vomit at the end. That’s part of you blowing through the glycogen so fast and before you can recruit other forms of energy.
Do these fast-twitch muscle cells release glygocen when the body is running low on glucose and vice versa? Would having more of these muscles then help regulate blood sugar levels? I.e. "do bodybuilders get hangry?"
I don't have any formal medical training but according to the science I'm aware of answer should be no. However when you start to lose weight the first thing you lose is muscles. (Muscle is more dense than fat)
At 14:02 you explained how type I fibres (oxydative) could convert to type IIx fibres (glycolictic) basednon the rype of workouts one engages in long term. But i came across an explanation that type IIx fibres cannot increase in number from what you're naturally born with. Correct my understanding. Appreciate the content.
What fiber type does my judo where I have to do repeated high intensity, high load and high explosiveness actions for potentially back to back repeated 5 minute bouts?
Interesting. Fast oxidative was the type for me. Initially I wanted fast glycolytic but it didn't suit me. And slow oxidative was never my style. For I while did strength training and sought fast oxidative muscle fibers.
@scottessery100 he says there is another video about motor unit requirement, and I could not find it by just searching. But I DON'T know what YOU are thinking about 😂🤷♂️🤔.
How about if I spend 80% of my training working at slow twitch and 20% medium to fast twitch, will the fibres I have be better adapted at both or is there a trade off? Will I lose some of my enduring fibres working on speed or will both simply get stronger?
@@theljbrotherhood3553 Good question. Crossfit has opened my eyes to the potential of the human body. Crossfit has shown the ability to be strong and have great endurance.
Does it really matter? The consistency is what really matters. It isn't like you can tell your body to produce more fast twitch muscle fibers or slow twitch muscle fibers or hybrid.
@ Bloxian Depending on your goals, strength vs hypertrophy, your training will vary. Generally, strength is best trained with low reps (1-5) but not to failure whereas hypertrophy uses higher reps (5-30) training much closer to failure. Ultimately you have to learn what works best for you. Some good sources are: Jeff Nippard Mike Israetel Jeff Cavaliere Ryan Humiston Dr Milo Wolf. Lots of tips but consistency and good nutrition would be near the top.
4:12 So this explains why a fish that does a lot of sustained fast swimming like a bluefin tuna will have dark red meat, and a fish that does a lot of sitting and waiting for a quick ambush like a halibut or bass will have white meat.
I believe fast twitch and slow twitch are both psychological factors affecting muscle twitch speed; all dictated by genetics and by how fast or slow someone in your environment moved. Mother or father and who you were more attached to
@ I understand there are physical differences between the two but where does the speed come from; it comes from the mind; people in you environment and their idea of fast or slow
This finally explains why I can swim laps for an hour with no breathlessness, but can only hula hoop for a handful minutes before I'm puffed out and sweating.
When people say “lots of muscles is good for your health bc they burn carbs overnight”. Don’t they go into action “only” when doing intense / quick movements?
Fast twitch fibers are more prone to atrophy for everyone by virtue of being larger and fatigueable (and, thus, also more prone to hypertrophy). Any population susceptible to atrophy and sarcopenia will see greater losses to fibers that have more to lose.
As we age, our fast-twitch muscle fibers-responsible for quick, explosive movements-shrink faster than slow-twitch fibers. This happens primarily because the nerves that signal these fast fibers tend to decline, so these muscles get less stimulation and weaken over time. Additionally, fast-twitch fibers aren’t used as much in everyday activities, which rely more on slow-twitch fibers for endurance. Without regular activation, fast-twitch fibers lose size and strength quickly. Finally, since fast-twitch fibers have less blood supply and endurance than slow-twitch fibers, they’re less resilient to aging and atrophy faster. By Ai
I also read that it’s also partially due to the way human physiology evolved in a world of scarce resources. Fast twitch fibers are the most energy and resource intensive. The body will attempt to maintain the bare minimum. That’s why it’s “use it or lose it.” You’re fitting 100,000’s years of evolution.
@suran396 I could run when I was little for hours but only at a light jog . My boys have the lung capacity I don't have . My girl doesn't run for health reasons .
Great video but you are 100% wrong that you can convert type 1 muscle fibers into fast twitch muscle fibers. Not even close. It will never happen!!!! I am going to make a video debunking what you just said. It's simply absurd. They could go back and forth in their own subtype, but there is no turning a slow fiber into a type 2X. Come on, man!!!!! In other words, you are claiming you can convert low-threshold motor units into high-threshold motor units. Simply absurd!!!! It's not happening! The only fibers that can do this are hybrid I/IIa/IIx fibers. And people are born with these. These specific fibers work back and forth in their own subtype. You are not converting a pure slow twitch fiber that does not contain myosin heavy chain isoform composition of a type 2X fiber into a pure fast twitch type 2 X fiber.
![Felix "Unfair" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/Oswujxm2Ag0/mqdefault.jpg)
Being a certified fitness trainer, I must confess that I keep my knowledge of human anatomy up to date from this channel. Thank you for these valuable videos.
You should take the time to learn biomechanics
Same as a sports science student it really helps me in my studies.
Same, not everyone gets the opportunity to study to this degree, with real cadavers.. very informative visually and much can be learnt!
Perfect timing, I have an A&P exam on the muscular system in a few days. I just learnt all of this so this is a good recap.
Lol
I been lifting weights (mostly heavy) for about 15 years, over a year ago I started with mma training, it’s amazing to see how the body adapts itself, mma is a mix of training, you need endurance, you need to be strong and fast so basically you train all the muscle fibers, energy systems and trying to find best balance that would suit the needs of that sport, body is an amazing machine. Love your content!
u do nawt need endurance for mma blud
How have your joints and bones held up
@@breadman5048 thats skeletal endurance im talking about pure muscular endurance like can you believe pro cyclists use over 5000 calories per ride and they intake that during the ride aswell? so their muscles have hugeeeeeeeeee aerobic efficiency
but yea i respect the ears!
@@nishanperera6874 sure but I was asking the OP
As a sprint athlete who used to be forced to do a bunch of aerobic training, I LOVE this topic! It’s been one of my favorites to talk about to my peers for years! So happy to see yall made a video on it!
This was really cool, I did track in high school, I was not a good sprinter, and I did not have the endurance of the cross country kids. But I crushed people in the 800. Learning about this third Type IIA fiber explains a lot to me.
Excellent, I studied these concepts already but it was a sisyphean task to remember it, but the visualization and the practical relations just might do it! Thank you!
Love all the exercise physiology related videos on your channel, keep it up!
You quickly became one of my favourite channels on YT
I had an honors class where we had to pick a topic and I chose to do mine over the different types of muscle fibers! Over 20 pages and over 30 sources later and it’s done! Love how interesting this stuff is!
As a professional athlete this was very informative! Thank you!
Amazing video! I really like the chart summary which easily points the key differences in the muscle fibers.
Thanks for watching!
My muscles are all lazy twitch.
My muscles are all lazy, not even twitching
😂@@yourfellowhumanbeing2323
Welcome mr.Sloth 🦥
Lmfao
As a sports science student, this channel really helps me a lot in my studies. ❤
Happy to hear that!
Quite informative. I learn and unlearn a lot from your channel daily. Thank you Institute of Human Anatomy.
Really happy to hear you find the videos helpful!
As non-student I absolutely adore these anatomy videos
You’re amazing bro thanks for listening!!!❤
Thank you! Because of videos like this, I have added explosive exercises to my routine.
Thanks for all your hard work. I'm not a medical pro, but I love your channel because it gives good info on fitness and health for regular folks like me. I also get useful tips from Dr. Aaron Horschig's Squat University channel. Much love and best wishes.
1:50 Genetics 14:30
5:30 Fast twitch fibers
7:30 Fast oxidative
10:30 Recap
Been following you since the Covid19 Era and i must say this is pretty good content and educational 👍
"Great video! Thank you for this content!"
- 1500m track athlete aka fast oxidative-glycolitic user
As a professional athlete, I found this incredibly informative! Thank you so much for sharing this!
🙌🙌🙌
I m a male type 2 predominant. I struggle to keep up with endurance training. For this matter, my FTP on the cycling power/watts calculation is just “good”. Even though I have been training for 3 years I hardly touched 3/watts kg. Now when it comes to repeating sprinting uphill or all out 2 minutes max power output, although very exhausting, I feel great about it and perform well, actually better than endurance alone.
What kind of training did you do, and how did you eat for your training?
just ride a lot of zone 2, and I mean a lot - ramp up to 5-8 hour rides, 20 hours+ per week. If you do that consistently for a season, you WILL see improvements, even if you don't do any more intensive rides.
Thank you jonathan❤
That fiber type conversion is so fascinating
I know right!
I have been a runner for many years now, running at least 6km’s a day, but with the onset of menopause I find that running is not helping anymore so I have started strength training . It will be interesting to see how my body adapts to these changes
You need transdermal bio identical hrt ( estradiol, progesterone and testosterone) when no medical contra indication as can be estradiol sensitive breastcancer. Dr. Louise Newson UK is giving awsome explanations. Check her out.
@@Claire-cj6nnis this spam
Thank you for another awesome video!
Excellent presentation.. can you please share the study 📚of twins about the change in fiber type? Thank you
Great information 👍🏼..
wonder how much the genetic fast/slow twitch fibre composition in the vocal chords(thyroarythenoid) affects singing ability? presumably those with more fast twitch have more powerful voices and thicker easier to adduct vocal chords than those with abundance of slow twitch?
I always knew tbis doing sport n things that use all muscle fiber types. Now I know the science behind it all.I know I do best sprinting.Becauae I was born a sprinter. I boxed,sprinted,and did long distance training. I definitely understand the differences.
Arnold Schwarzenegger had genetically small and weak calve muscles and early pictures show him up to his knees in water. However, after being ribbed by other bodybuilders he put in an all out effort into his calve training until they became his best body part. Great video.
Thanks for informative content. 👏
Glad you like it!
Excited for this!
Nice to see your co-host Jeffrey in this one, but maybe you could let him speak some of the time? ;)
😂he would probably just rattle on and on.
I'm hoping he will address musicians; pianists in particular (because I am one). Also, there is a difference in the neurological development between string players and other musicians.
There very well may be, or possibly absolutely is, a difference in the neurological development of different musicians, since their instruments require different physical skills (I.e. wind versus piano, etc)
2A sounds like the best of all worlds
I like that guy on you saying it's going to be a twitchy.
Does a sprinter or marathon runner beef make a tastier steak?
I need to know as well... for science. 😊
Cows from the mountains usually have a stiffer steak
Marathon, guy.
the marathoner , cuz more capillaries and slow fibers and more fat, hes tastier😂🎉😂🎉...game hunters like a 1 head bullet shot, cuz they say if you injure him so he lives a few more seconds the adrenalin spoils the meat, its not tastey meat
Some folk built like this, some folk are built like that. But the way I am built, a- don’t you call me fat because I am built for comfort, I ain’t built for speed. But I got everything all the good girls need. 😂🎸✌️
I'd love to see you do a program on Brown Fat.
finallyy yess!! thank you
🙌🙌🙌
Wakenya hatuwezi kosekana hapa
It's a big reason I do both heavy lifts as we all higher rep days. Building both IIa and IIx help for long term functional strength. Yes, I'm a total nerd in the gym
agree
Hi could you do a video next on how having/not producing ACTN3 alters the functions of these fibers ?
I wish, so very much, that I had the ability to study this scholastically, as opposed to RUclips enthusiast
I really want to see an eye sectioned. Can't find any pictures of it and I'm really curious about the pupil. Its just a black dot....
Do a video explaining creatine
Already did
13:40 What was that twin study referenced here? I'm wondering if the difference found was in volume of muscle fiber type or in the quantity of fibers, as you suggested. My understanding from reading up on current muscle tissue literature is that while you can certainly encourage the growth of one fiber type relative to another, no one has definitively shown muscle fibers to change types *in humans*. Just because we see it in other related organisms like mice is not a guarantee that it happens in humans.
But what are the effects of those transitioning fibers on human body?
How does that influence a human body in it's lifetime?
What should be aimed for?
Are fast twitch better?
How is this different for those of us with α-Actinin-3 deficiency?
So, for being healthy we, ideally, need to do all types of training to include all of the muscle types?
Whatever training you choose will convert your fibers. The healthy minimum is 150mins cardio exercise and 2 days of weight training
As long as you're physically active with proper nutrition, you'll be healthy. You only need to workout these muscle types based on your goals.
What type of fibers am I building doing varying intensity, low-mid-low weight, long duration, full range of motion, varying speed, weighted shadowboxing and movement drills?
I use 2 between 10-15-25-30-40lbs weights counting up and down and am obviously slower the higher the weight. The workout includes explosive footwork, squats, lunges, and every kind of arm workout. I go for well over an hour usually and sometimes for +4 hours with hot-cold-hot showers in between.
Is there a way to test muscle type composition while still alive?
yeah, just test your results in sports
so the fastest way to deplete glycogen storage is to perform explosive movements to activate the fast-twitch fibres
Think about any sprint or explosive effort where you felt dizzy and wanted to vomit at the end. That’s part of you blowing through the glycogen so fast and before you can recruit other forms of energy.
Can someone provide link or name of the video of the motor unit recruitment？
Can't find it
Thank you
Do these fast-twitch muscle cells release glygocen when the body is running low on glucose and vice versa? Would having more of these muscles then help regulate blood sugar levels? I.e. "do bodybuilders get hangry?"
I don't have any formal medical training but according to the science I'm aware of answer should be no.
However when you start to lose weight the first thing you lose is muscles.
(Muscle is more dense than fat)
At 14:02 you explained how type I fibres (oxydative) could convert to type IIx fibres (glycolictic) basednon the rype of workouts one engages in long term. But i came across an explanation that type IIx fibres cannot increase in number from what you're naturally born with. Correct my understanding. Appreciate the content.
How do the different fiber types respond to a training stimulus?
Now i understand why my legs start burning after like 10 min jogging
Heh. Mddle distance runners rule!❤❤❤
How about when you do many reps with low weight? like above 30 or 50 reps in a row, do you still use slow fibers or the fast ones also activate?
Can you train fast twitch fibers while training slow ones ? I’m a fighter I have been thinking into adding some type of weight training
Does the eye's muscles have more Type II fibers than type I?
Type IIx and IIa muscle fibers can be converted to type I, but the reverse is not possible.
are you saying that once you have conditioned yourself to endurance you can't go back to strength?
So a sprinter can become a world class. Marathon runner but the reverse is not possible?
What fiber type does my judo where I have to do repeated high intensity, high load and high explosiveness actions for potentially back to back repeated 5 minute bouts?
fast-twitch fibers
Interesting. Fast oxidative was the type for me. Initially I wanted fast glycolytic but it didn't suit me. And slow oxidative was never my style.
For I while did strength training and sought fast oxidative muscle fibers.
10:10 what is the video he is referring to 🤔
Dunno what are you thinking 😮
@scottessery100 he says there is another video about motor unit requirement, and I could not find it by just searching.
But I DON'T know what YOU are thinking about 😂🤷♂️🤔.
My teen son is doing very well in 5k and 1600m, but has some trouble with leg cramping. Advice?
Getting enough sodium, potassium, and generally being hydrated and warmed up (not stretching though)
Thought they already covered the subject with a previous video
My brain is 100% Twitch these days
Consider adjusting it to 90% of that amount and 10% of IOHA. 😉
Yes, I have my brother. I think he works out cause he has a lean, nice muscle, body. No, I am not, or neither is he like that.😊❤❤
I have a brilliant question, if you die ( and we all hope it doesn't happen ), are you going to be the mascot cadaver of the channel?
How about if I spend 80% of my training working at slow twitch and 20% medium to fast twitch, will the fibres I have be better adapted at both or is there a trade off? Will I lose some of my enduring fibres working on speed or will both simply get stronger?
@@theljbrotherhood3553 Good question. Crossfit has opened my eyes to the potential of the human body. Crossfit has shown the ability to be strong and have great endurance.
I needed a good video on this topic since i started working out and can't really find a very informative description of each fibre types...
It's really simple. Slow twitch is for endurance.
Fast twitch is for sprinting.
@@RealMTBAddictyou forgot the strength/bodybuilding aspect of it
@@pandajohn5911I don't see you adding anything to the conversation.
Does it really matter? The consistency is what really matters. It isn't like you can tell your body to produce more fast twitch muscle fibers or slow twitch muscle fibers or hybrid.
@ Bloxian Depending on your goals, strength vs hypertrophy, your training will vary. Generally, strength is best trained with low reps (1-5) but not to failure whereas hypertrophy uses higher reps (5-30) training much closer to failure. Ultimately you have to learn what works best for you.
Some good sources are:
Jeff Nippard
Mike Israetel
Jeff Cavaliere
Ryan Humiston
Dr Milo Wolf.
Lots of tips but consistency and good nutrition would be near the top.
Wow never been this early 😂❤.
Díky.
According to my DNA test, I am 50/50. Both equally fast and slow twitch. I have a very hard time building large muscles.
which fibre type burns the most fat if there is a difference in fat burning
The real scientific question for me is: Why am I bad at both strength and endurance 😢
can't wait to learn about some quality education! :>
Or in my case …. I don’t I think I have either 😢
4:12 So this explains why a fish that does a lot of sustained fast swimming like a bluefin tuna will have dark red meat, and a fish that does a lot of sitting and waiting for a quick ambush like a halibut or bass will have white meat.
I get itching in both.
Does it mean If I train both long distance running and strength training I am missing out, than if I just trained one sport?
You will gain more benefit doing both than you would lose.
The opposite, actually.
I can't do anything fast, seems like I'm all slow oxidative fibers lol
Is this the guy from Dirty Medicine?
I believe fast twitch and slow twitch are both psychological factors affecting muscle twitch speed; all dictated by genetics and by how fast or slow someone in your environment moved. Mother or father and who you were more attached to
There are physical differences between the muscle fibre types, it's not just in the brain
@ I understand there are physical differences between the two but where does the speed come from; it comes from the mind; people in you environment and their idea of fast or slow
This finally explains why I can swim laps for an hour with no breathlessness, but can only hula hoop for a handful minutes before I'm puffed out and sweating.
When people say “lots of muscles is good for your health bc they burn carbs overnight”. Don’t they go into action “only” when doing intense / quick movements?
Having more muscle mass burns more calories at rest, yes, it just does.
I'm a regular ol anatomy nerd. Lol
Is this why you can't build much muscle mass with isometrics?🤔
you can, what are you talking about. just hang onto something
Wow good thing I don’t have any muscle
Why do fast twitch seem to atrophy faster than slow twitch as we age later in life?
Would love to get an answer to this!
Fast twitch fibers are more prone to atrophy for everyone by virtue of being larger and fatigueable (and, thus, also more prone to hypertrophy). Any population susceptible to atrophy and sarcopenia will see greater losses to fibers that have more to lose.
As we age, our fast-twitch muscle fibers-responsible for quick, explosive movements-shrink faster than slow-twitch fibers. This happens primarily because the nerves that signal these fast fibers tend to decline, so these muscles get less stimulation and weaken over time. Additionally, fast-twitch fibers aren’t used as much in everyday activities, which rely more on slow-twitch fibers for endurance. Without regular activation, fast-twitch fibers lose size and strength quickly. Finally, since fast-twitch fibers have less blood supply and endurance than slow-twitch fibers, they’re less resilient to aging and atrophy faster.
By Ai
I also read that it’s also partially due to the way human physiology evolved in a world of scarce resources. Fast twitch fibers are the most energy and resource intensive. The body will attempt to maintain the bare minimum. That’s why it’s “use it or lose it.” You’re fitting 100,000’s years of evolution.
*fighting*
💪🏽
💪
I try to be fast, but I prefer slow. 🐢
The rabbit, never finishes the race. 🐇
I'm not lazy but I don't have white muscles 😢
I always had a lot of energy but the lung capacity has never been there .
Me too. And bloodwork showed I have low hemoglobin. My brother, and my son, however, can run, and run, and run......
@suran396 I could run when I was little for hours but only at a light jog . My boys have the lung capacity I don't have . My girl doesn't run for health reasons .
got smarter in 5min 😂
Great video but you are 100% wrong that you can convert type 1 muscle fibers into fast twitch muscle fibers. Not even close. It will never happen!!!! I am going to make a video debunking what you just said. It's simply absurd. They could go back and forth in their own subtype, but there is no turning a slow fiber into a type 2X. Come on, man!!!!!
In other words, you are claiming you can convert low-threshold motor units into high-threshold motor units. Simply absurd!!!! It's not happening!
The only fibers that can do this are hybrid I/IIa/IIx fibers. And people are born with these. These specific fibers work back and forth in their own subtype. You are not converting a pure slow twitch fiber that does not contain myosin heavy chain isoform composition of a type 2X fiber into a pure fast twitch type 2 X fiber.