T Nation

Say it Ain't So Type IIB Not All That big?


Am I wrong in thinking this goes against what all or nearly all fitness/bodybuilding instruction says?

That TypeIIB fibers are NOT Bigger then Type I


Waiting for Professor X to respond


That article doesnt address it, but I believe that the IIB fibers receive all the press because they have the most potential for growth, not because they are the largest to begin with IN NON-TRAINED humans.


They were not the biggest in NON-TRAINED young adults - which doesnt mean they don't hold the biggest hypertrophy potential and aren't the biggest in TRAINED adults.

Oh and btw. -> What difference does it make, do what stood the test of time and not what stood the test of a single lab study.

EDIT: to whats written by the above poster: X2 ^^


Well said. That article isn't relevant to bodybuilding. We don't see hyperplasia in humans either.

In fact, I don't even remember the size of UNTRAINED Type IIB fibers even being an issue of discussion.


Yes the article states NON-TRAINED but the question is why do you BELIEVE that it's any different for growth?

That's your opinion. With the increase of bodybuilding/Fitness Coaches reciting type IIB fibers "Growth" potential to promote there programs I'm sure there are people who want to know the actual facts. You can't go two articles on a site without a push for high speed low rep set to improve muscle size. Yet there's appears to be nothing to substantiate this, nor too many champion bodybuilders who used it.


No, one has to prove the opposite. The study being on non-trained individuals means it doesn't apply to issues of muscle growth.

I can claim a study on ants proves the sky is purple, and by your logic to contradict me and the study, you'd have to prove the sky isn't purple.

This is as useful for BBers as a study on ants.





A little off topic here but...looking into muscle types and training accordingly was one of the worse routes I ever went down when getting into training.

All sorts of stupid stressful thoughts comes across your mind:

"OMG, what if while I'm training the type II fibres, the type I fibres atrophy??!!"

"I should train all the fibre types otherwise I'm missing out on 9.678% of possible gains!"


Bodybuilding is more of an art than a science - you improve on how your own body responds and gain experience, rinse and repeat...you don't need to know WHY it happens. And you don't need to be changing things all the damn time.

Ironically, worrying less about all that stuff will probably make you grow more simply because of the reduced cortisol levels :stuck_out_tongue:


Its in Sport Biomechanics, not even a physiology journal, not even in the top 50 or 60 Sports Science journals, there are usually reasons for an article having to go there so ignore.


Regardless of that, the size of "UNTRAINED muscle fibers" means abolutely nothing to bodybuilders.

I was a kid with small muscles. Does this mean that somehow tells you how much those small muscles could grow?

Of course not.

If the size of untrained muscles mattered at all, everyone would be limited by the size they started with.

The OP apparently didn't understand this....which is why "a little knowledge" can royally fuck you up.

That is why lay people can make mistakes when trying to look at scientific research with no formal education.

I know they hate to hear that, but it's the truth.


LOL "They" hate to hear that? "lay" people? lolol WTF are you? What Pro Card are you walking around with? Who did you train from "lay" to pro card status? A group of T-Nation Followers doesn't qualify somebody as any more knowledgeable than "Lay" people. Your truth is not truth but some twisted frame of mind.

Muscle is muscle, it can be broken down into different types, whether fast or slow, trained or untrained knowledge of different types helps. The post was to people who care about the science of it, not those that feel like typing "who cares?". It's a challenge to all those that follow the coaches that say differently, since those coaches all claim it science. Yet all anybody can say is it doesn't apply to us, yet nobody can prove it.


Kingbeef- How the Hell do you ever think you're going to get yourself to look like that jacked dude in your avatar if you don't obsess about these things? Sheesh.


"lay person" is not an insult. It means you didn't go to school and learn how to do research formally and don't have a formal scientific background.

That doesn't require a "pro card". It requires a degree.


The only true statement is Layperson is not an insult and I did not take it as one.


? Dude, you CLEARLY (to anyone with any science background) misunderstood some of the discussion surrounding fiber types. You assumed that the size of an untrained muscle fiber had jack shit to do with growth potential. You have people here with backgrounds in this telling you what the deal is.

You all ask why education gets brought up so much. This is why.

For some reason, you think the guy in the room who went to school for this shit is the clueless one.

That makes as much sense as this thread.

Hate all you want, but I wrote this shit to help you understand. It is up to you if you can even see that.


Because bodybuilders (whose training requires greater use of type II fibers) have bigger muscles than marathon runners, distance swimmers, distance cyclists (whose training requires greater use of type I fibers).


The bigger question should really be...

EVEN if this is true how does that change the way YOU will train?

Me? I'll still keep sticking to things that have worked for me to get bigger and stronger for years now. I would lift exactly the same had I no knowledge whatsoever of muscle fiber type.

Your lifting/eating/cardio should be based on RESULTS, not based on single pieces of scientific information shown in isolation.


The concept of slow sets vs. "accelerating" the weight is about trying to eliminate momentum (so the muscle does all the work). Lifting explosively is just trying to beat the weight to the finish line.