Which Muscle fibre types cause hypertrophy?
- 12-06-2013, 05:01 AM
For years I thought that it was the Type 1 slow twitch fibres that cause hypertrophy and Type 2 fast twitch caused strength gains. But after some research people are saying its the Type 2b fast and slow twitch fibres that cause hypertrophy done at 60% + of your 1rm at a fast and explosive rate for 3 reps and a 30sec rest for 10 Sets. I have searched Google for the answer but can't find it. Can anyone help?
- 12-06-2013, 12:42 PM
you cant find the answer as fiber types do not cause hypertrophy. maybe its just your terminology though.
all fibers types can become larger through hypertrophy. yes, some types can grow more so than others, but they all can. a simple way to make sure you are stimulating all of them is to go to concentric failure on the last set of an exercise. that is no matter the rep range. the point of that recommendation is intensity not hitting a specific rep.
make sure you eat enough, make sure you sleep enough, make sure you recover enough, and you will grow even on a bad program. over the years you will find what works well for you. after a few more years you will realize what works is mainly based upon the fact that you believe in the program so you work harder at it. in other words, hard work, hard eating, and hard recovery makes a muscle big.
now if you want to learn the mechanisms and much more detail then i recommend getting a college level anatomy and physiology book and start reading.you can call me "ozzie" for short.
- 12-07-2013, 01:24 AM
12-07-2013, 09:25 AM
your body can shift over a long period of time between type 1 and type 2 fibers. You'll never get rid of all type 1 or type 2 fibers, but it'll be more unbalanced like a 40/60 ratio. As far as hypertrophy, you won't see an extent of hypertrophy in type 1 as you would type 2s.
Serious Nutrition Solutions
12-08-2013, 12:23 AM
Type II is primarily responsible for muscle hypertrophy. Type Is can experience hypertrophy, but often at the expense of generalized (type II) hypertrophy
The above is my own opinion and does not reflect the opinion of PES
12-08-2013, 05:46 AM
12-08-2013, 12:21 PM
Both types can hypertrophy. However different rep ranges favor different types of growth. Type Ia (oxidative) and type IIb/x (fast/glycotic). Type Ia slow twitch fiber are more oxidative as they have more myoglobin thus are more beneficial for (and respond to via) endurance than the type IIb/x fibers. The portion of the cell that fuels this type of exercise that favors Ia oxidative fibers IIRC comprises 65% of the cell. That's why you can gain size quickly using high rep schemes. It's not all fascia, though but water, amino acids, glycogen, growth factors, etc..
If it's explosion you want (referred to as power) then you need to work on your bar speed and maximal output. A good example of bar speed work would be pause rep bench-press where you put ~40% 1rm on the bar and let the bar rest on your chest for 4-5 secs to eliminate stretch-reflex. Then exploding the concentric portion as fast as possible. I've had tremendous results out of the hole w/ this. It also gives the CNS a break.
The maximal strength half of the equation is kind of self-explanatory. Increase the weight at which you can perform everything explosively.
Hope this clears things up a bit.
12-08-2013, 03:26 PM
12-08-2013, 05:00 PM
I don't think you can stimulate one type of muscle fiber without activating others
12-08-2013, 05:57 PM
12-08-2013, 08:01 PM
as the good doctor Zir Red posted earlier this year, going to concentric failure is what is important more so than doing 5 or 10 or 15 reps.
you can call me "ozzie" for short.
12-08-2013, 08:53 PM
- 5'10" 220 lbs.
- Join Date
- Jan 2006
OP, what you posted was something probably posted about the Westside method and their dynamic effort. This is not intended for hypertrophy as it is intended to work on both bar speed and technique in addition to training the body to use more motor units.
M.Ed. Ex Phys
12-08-2013, 09:51 PM
12-09-2013, 02:08 AM
If you lift above 60% of your 1rm for 3 very explosive reps with a 30 second rest you will recruit both fast and slow twitch.
12-09-2013, 03:03 AM
I'm pretty damn sure the "all or nothing" principle works here. Your body doesn't select which fibers to have your neurons activate. A flexed muscle is a flexed muscle. Yes they may grow due to different stressors but activation is activation.
Also not sure how oxidation/Krebs/glycolisis work for anabolism in the sense of this question considering that refers to energy production and use of atp/what not.
"No citizen has a right to be an amateur in the matter of physical training...what a disgrace it is for a man to grow old without ever seeing the beauty and strength of which his body is capable." - Socrates
12-09-2013, 04:08 AM
12-09-2013, 06:49 AM
12-09-2013, 01:20 PM
Well, a motor unit is the motor neuron and all the muscle fibers it innervates.
Here is one regarding fiber types, recruiting, and conversion: especially note slides 10-20
Check this out. The whole thing is good, but for the sake of fiber type and training you may want to start around slide 84:
A few things.
1. We two muscle fiber types, and a total of 7 subtypes:
There is no interconversion (i.e.: you cannot convert a type I to a type II...not in humans)
There is intraconversion (type II subtypes can be converted toward IIx or IIc)
With strength training IIx are almost all converted to IIa or IIax..depending on the type. IIc's are also converted this way. The more explosive and short the sets, the more they go toward IIax. the longer the sets the more they go toward IIa.
With strength training, just about all fiber will hypertrophy. IIa seem to have to the greatest potential.
You will see on slide 18 of presentation 1 that type IIX basically runs out of energy after 4 sec of all out work, this relates to slide 16 where you will note how fast IIx fatigue. This is why the adaptation with typical strength training, where sets take 15-30 seconds, is the intraconversion of IIx to more fatigue resistance IIax and IIa.
12-09-2013, 03:59 PM
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