Thread: FT & ST fiber identification & your body type

The easiest way to approach this subject is to start by explaining twitch fibres, I might get this wrong so be kind, its been a while. I have simplified this as much as possible without (hopefully) losing credibility.

There are 2 basic twitch fibers, and I think 4 total fiber types (TI, TII, TIIX & TIIB ) for now we will stick with FT I & FT II.

Type I - also known as red or slow twitch fibre (STF )

This fibre is basically an endurance / aerobic fibre, elite marathon runners, triathletes, cyclists etc usually have higher ratios of this fibre. I read a study once that claimed women on average tend to have higher ratios of STF.

STF move more slowly than FTF ( about half the reaction speed ) and are able to do repetitive continuous movements with greater ease as they generate ATP via efficient oxygen conversion, (hope that makes sense.)

Type II - also known as white or Fast twitch fibre (FTF)

FTF are interesting in that unlike STFs they are anaerobic by nature (without air/oxygen) These fibres are able to move faster ( around 100 -110 ms) with bursts of strength but they accumulate lactic & tire faster. If you are involved with sports that require quick burst of power then FTF are an asset for sure. I read an article on one of the boxing forums once that stated good boxers tend to have a mix of fast and slow fibres with the greater percentage being Fast TF in the upper body. This allows for speed & power, due the the fact boxing unlike cycling allows the FTF time to relax briefly and continuously thus allowing them to reset without exhausting to quickly. That's quite a genetic advantage.

The simple facts are we as a species generally speaking have both major fiber types distributed in each muscle, this is for obvious reasons, strength, speed and endurance combined is far better for survival than just one or the other.

Identifying your twitch fiber ratios without providing tissue samples can be done with a little self knowledge and common sense.

You need to firstly divide your body into isolated major muscle groups and find an appropriate exercise that woks the area your trying to identify. You will need to have a balanced training meal 40- 60 minutes prior to this test be well hydrated, well rested and able to focus without distraction.

*****Select your muscle group and isolation exercise, then with a rep range of 8 -12 over 5 sets. ( 1 warm up set 4 working sets) record the max weight you lift for reps.

This will give you your working max weight for reps... record this and continue with your normal day in the gym, just ensure that your first exercise that day was the isolated muscle group you wanted to identify as we do not want to contaminate results with cross or secondary involvement fatigue.

A few days later when fully recovered, do as before, have a balanced training meal 40 - 60 mins prior, ensure your hydrated, well rested and able to concentrate etc

*Select a weight approximately 20% of your max weight for reps as noted in your diary.

*Now do a warm up set again between 8-12 reps, Rest for exactly 60 seconds, then quickly select a weight approx 80 percent of your max and lift it aiming for 20 reps.

*Make a note of where lactic started, where you faulted and finally how many you completed.
( this test should be done 3 times over 3 weeks to successfully map fibers)

It will look something like one of the following:

5th lactic - 14th faulted - 19 completed.


What does this tell you? .. It's quite simple.

*Type 1 fibers (slow) tend to work best over a rep range of 12 - 20 even under moderate weight. - slow lactic release

*Type 2 fibers ( fast ) tend to work best over a rep range of 1 - 5 under moderate to heavy weight - fast lactic release.

Your results will show you:

*A slower lactic release rate with a slower falter and lower failure rate denote Slower twitch fibers.

*A faster lactic release rate with a faster falter and higher failure rate denote Faster twitch fibers.


Sometimes a rate will vary slightly and may not always match lactic, falter or failure rates at times, this is possibly due to an incremental genetic balance of FT II A(x) or B - (ATP decline or stay via glycolysis or oxidation)

I realise this is not a perfect science but it does help show you a bias worth mapping and using for tailored training without the need for medical testing.

The best advice I can give is understand that we all have a mix of fibers, so to neglect a fiber type is to leave fibers untrained.

Shake up your rep ranges and open your mind to utilising various methods of training from isometrics to resistance and more.

If you bias toward a fiber type then train for that type IE -

*FTI - rep ranges of 12-20 less time between sets.

*FTII - rep ranges of 0 - 5 more time between sets.

Intermediate & mixed fibers rep ranges of 8 -12 medium time between sets.

But no matter what fiber type you bias, German 10 x 10 training for major muscle groups once every 10 - 12 weeks will do some amazing things.

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~R~

So Razz, could you design a program that would cover all fibers by pyramiding weight up and cycling reps down, to get at all FT in a single session.

example only for clarification. which i would think would pretty well get at all FT

squat after warm up

1x80x20
1x100x15
1x120x10-12
1x140x6-8
1x160x3-5

Also i think this is some of the science that Brian Haycock based his HST training protocols on, week1-2 is 15-20 reps, week3-4 is 8-12 reps and weeks 5-6 is 5-8 reps.

Youde probably get more positive stimulation from splitting your fiber training up into a 3 -4 week rotation. You will need to hit Fast , Slow & intermediate fibers, just make your personal bias in training to lean toward your dominate ratio of twitch fiber.

I made an example of this over here, just look for my post ---->

Training Link

Something I did loosely note, was your body type in many cases can tell you alot about your twitch fiber genetics before you even lift a weight re Ectomorph, Mesomorph, Endomorph.

It's just an opinion but take a read through these body type profiles and see if you can fiber type each classification yourself.

Ectomorph:
An ectomorph is a typical skinny guy.
Ecto’s have a light build with small joints and lean muscle. Usually ectomorph’s have long thin limbs with stringy muscles. Shoulders tend to be thin with little width.

Typical traits of an ectomorph:
Small “delicate” frame and bone structure
Classic “hardgainer”
Flat chest
Small shoulders
Thin
Lean muscle mass
Finds it hard to gain weight
Fast metabolism


Ectomorphs find it very hard to gain weight. They have a fast metabolism which burns up calories very quickly. Ecto’s need a huge amount of calories in order to gain weight. Workouts should be short and intense focusing on big muscle groups. Supplements are definitely recommended. Ectomorphs should eat before bed to prevent muscle catabolism during the night. Generally, ectomorphs can lose fat very easily which makes cutting back to lean muscle easy for them.

Mesomorph:
A mesomorph has a large bone structure, large muscles and a naturally athletic physique. Mesomorphs are the best body type for bodybuilding. They find it quite easy to gain and lose weight. They are naturally strong which is the perfect platform for building muscle.

Typical traits on a Mesomorph:
Athletic
Hard body with well defined muscles
Rectangular shaped body
Strong
Gains muscle easily
Gains fat more easily than ectomorphs

The mesomorph body type responds the best to weight training. Gains are usually seen very quickly, especially for beginners. The downside to mesomorphs is they gain fat more easily than ectomorphs. This means they must watch their calorie intake. Usually a combination of weight training and cardio works best for mesomorphs.

Endomorph:
The endomorph body type is solid and generally soft. Endomorphs gain fat very easily. Endo’s are usually of a shorter build with thick arms and legs. Muscles are strong, especially the upper legs. Endomorphs find they are naturally strong in leg exercises like the squat.

Typical traits of an Endomorph:
Soft and round body
Gains muscle and fat very easily
Is generally short and “stocky”
Round physique
Finds it hard to lose fat
Slow metabolism


A combination of body types.
These body types aren’t set in stone. In fact, most guys have a combination of two body types. These combinations are either ectomorph/mesomorph or mesomorph/endomorph. It is not uncommon to find a pure mesomorph that gains weight like an endomorph for example.

So which body type are you?
Given the information above you should easily be able to identify your body type. You may also want to optimize your diet and training to suit your body type.

One final point I want to mention is that no matter what your body type you can build a big, ripped, muscular physique. Even the skinniest of guys can bulk up. Yes, it’s harder but if you’re willing to put in the hard work it can be done. link

Razz when determining body type are we talking about our type as younger adults? I'm very different today than to what I was up until I was 19 and made a fateful mistake in getting married.

Originally Posted by take2

Razz when determining body type are we talking about our type as younger adults? I'm very different today than to what I was up until I was 19 and made a fateful mistake in getting married.

great question, and i too have changed dramatically from when i was 19, however i would say what you where when you were younger is what you still are today, though just in a different form, also look at your mum and dad, people say genetics don't matter, i tend to disagree, i think they mean a lot but should not be an excuse for personal short comings.

Ok, thanks for that; although I'm still struggling to define exactly what type I am :)

Originally Posted by take2

Ok, thanks for that.

no worries, but that is only anecdotal remember, so what body type are you.

me i am an Endo with a leaning to Meso, not a lot though, thanks mum and dad

to all the pure mesomorph bodies out there, and I believe there are only a few unfortunately, i hate you and your god damn genetics.

Im a Mesomorph.. I'm insensitive at times because I often forget how hard other people have to work for the same gains.

Okay firstly thanks for answering my question razz.
Secondly i have a few questions.

Originally Posted by RazZ

Something I did loosely note, was your body type in many cases can tell you alot about your twitch fiber genetics before you even lift a weight re Ectomorph, Mesomorph, Endomorph.

What are the twitch fiber genetics for each each body type?
for example once you have identified your self as a ecto or meso.

Also are we talking about what identifying what exercises work for certain twitch fibers, or identifying what genetically is the more dominate fiber in your muscles, as my question was for the later and i think that's what we're talking about here but i'm really confused with the testing process.

Sorry as i'm 99% sure it's just me not being able to understand. I understand everything up to the testing process and i'm confused by what is meant by finding when lactic starts (is this muscle failure) and were fault starts.

Originally Posted by RazZ

Im a Mesomorph.. I'm insensitive at times because I often forget how hard other people have to work for the same gains.

And on behalf of everyone else, a big fuck you! j/k

I am a true ectomorph, I meet every requirement on that list you posted Razz. However I no longer have a flat chest or narrow shoulders, but that is due to hard work.

I have a good friend who is a very successful bodybuilder - he's the same height as me, except he's nearly 20KG heavier And I consume the same amount of calories he does...

Might be worth mention that type I fibers are much smaller and have the least amount of potential for growth.

Type IIb are much larger and have a greater potential for growth.

Originally Posted by M1CH43L

Okay firstly thanks for answering my question razz.
Secondly i have a few questions.



What are the twitch fiber genetics for each each body type?
for example once you have identified your self as a ecto or meso.

Also are we talking about what identifying what exercises work for certain twitch fibers, or identifying what genetically is the more dominate fiber in your muscles, as my question was for the later and i think that's what we're talking about here but i'm really confused with the testing process.

Sorry as i'm 99% sure it's just me not being able to understand. I understand everything up to the testing process and i'm confused by what is meant by finding when lactic starts (is this muscle failure) and were fault starts.

Can maybe anyone else shed any light on this?

People with high numbers of endurance fibers - slow twitch, tend to have thinner leaner physiques, gain slower and have faster metabolsisms. Think of long distance runners on TV.

People with high numbers of fast twitch fibers tend to have different builds again, thicker muscles, stockier builds etc. Think boxers, weightlifters, etc

Then there are those that are inbetween or of various odd ratios to either degree.

Apply these bodyshapes / body types very loosely to fiber specific traits and you generally see a pattern emerge.

Its very possible to be born geneticly predisposed to have possible talents based on twitch fiber ratios.
I read a study that shows it may just be possible to encourage a particular twitch fiber to increase in number through specific training.

I always keep a good mix in my training making sure no fibre is left untouched.
-Heavy weight, low reps
-a controlled weight, high reps
-fast explosive reps
-slow and controlled reps
...most of you know my deal anyway.

Having control and knowing what fibres need triggering and how to trigger them, puts you a step ahead all the time and hardly ever come across a plateu if everything else like diet and supps are upto scratch.

Great thread mate.

I'll ask again in this thread:

Body typing: done at what age? Do body types change with age?