I got into a discussion the other day about hypertrophy. One side argued was that there is no differentiation between sarcoplasmic hypertrophy and contractile hypertrophy and the other side argued that there was. What does everbody think out there.

Take the example of doing 60second speed squats vs. 6RM squats. if you will.

sacroplasmic hypertrophy is an increase in “whole” muscle size, myofibrilar hypertrophy is an increase in fibre size

Sarcomeric (myofibrillar) hypertrophy - the increase in the size and number of sarcomeres which comprise the myofibrils. This form is assoicated with an increased ability to exert strength.

Sarcoplasmic hypertrophy - increase in volume of non-contractile proteins and semifluid plasma with no corresponding increase in strength.

-source Supertraining 6th ed.


Principles, Bill Hartman’s post illustrates the definition of the two different forms of skeletal muscle hypertrophy.

In addition to that you must under stand, with respect to your example, that the 6RM defines an exact loading parameter, whereas speed squates for 60s only quantifies a duration and execution, not an entire loading parameter.

For example: performing speed squats for 60s with 30%1RM rates high on the myofibrillar hypertrophy scale. Whereas, performing speed squats for 60s with 10%1RM rates low on the myofibrillar hypertrophy scale. (Referenced Christian T’s table in Superman Sets)

Lastly, utilizing a 6RM load is right in the middle of the intensity zone that yields an compromise of size(sarcoplasmic hypertrophy) and strength(myofibrillar hypertrophy) gains.

James Smith

I need to clarify something. It was argued that when hypertrophy occurs there is no distinction with regards to the type (sarcroplasmic vs. contractile protein) and in fact they go hand in hand. Also, It was also mentioned to further the point that there have been no studies that have shown sarcoplasmic hypertrophy to have any real significance in terms of overall growth.

On the other side of the argument, it was said that you can increase in contractile protein without really increasing the volume of the cell.

In terms of the loading, 60 seconds speed squat @30% 1RM vs. 3RM squat. (NOTE: a slight change was made from 6RM to 3RM)

Question: which loading method rates higher for contractile protein growth (myofibrillar hypertrophy) and which for sarcoplasmic hypertrophy if in fact you can have one more than the other?

James, you mentioned that the 60" @30% 1RM speed squat rates high on the myofribillar hypertrophy scale. Is that method of loading more conducive to overall strength increases of contractile strength (myofribillar)? If so, then why wouldn’t powerlifters adopt this method to get bigger and stronger overall?

The terminology distinguishing between different types of muscle growth appears to be found in the writings of Zatsiorsky, Verkoshansky and Siff and possibly more recently Tsatsouline and now appears to be common currency in the strength training world.

I also have heard that it is a meaningless distinction but have absolutely no idea whether it is an accepted distinction by exercise physiologists or whether it is a mere hypothesis which has become a widely and uncritically accepted fact.

Perhaps those with an appropriate background can enlighten us some more?


Principles, to add to Bill’s post, I will also reference Supertraining…

Sarcoplasmic Hypertrophy-’…Although the cross-sectional area of the muscles increases, the density of muscle fibres per unit area decreases and there is no corresponding increase in muscle strength.’

Sarcomere Hypertrophy- ‘…Here there is an increase in the size and number of the sarcomeres which comprise the myofibrils. These may be added in series or parallel with the existing myofibrils, although only the parallel growth will contribute to an increased ablity to produce muscle tension. The area density of myofibrils increases and there is a significantly greater ability to exert muscular strength.’

Now, keep in mind that by utilizing specific loading parameters that one can simultaneously experience both kinds of hypertrophy, (i.e., 78.6-83.1%1RM 6-8reps/set)Poliquin1997.

As far as your question about which method rates higher for each different kind of hypertrophy, there are quite a few different methods for stimulating each type of hypertrophy.

The reference that I made concerning 60second sets with 30%1RM (performed explosively) is an example of a time under tension method that yields myofibrillar hypertrophy, along with muscle/power endurance, in contrast to typical methods used by bodybuilders.(Thibaudeau) Although this may be useful for a powerlifter, within the context of LA training or modified speed work, it in no way compares to the effects yielded by max effort work.

In Science and Practice of Strength Training, Zatsiorsky defines the three methods of producing maximal tension in skeletal muscle fibers. Repetition, Dynamic Effort, and Max Effort. He also states that the Max effort method is indeed the most effective for increasing maximal strength levels.

I believe that you would do well by purchasing the following texts: Supertraining (Siff, Verkoshansky), The Science and Practice of Strength Training (Zatsiorsky), And the translated texts from the Sportivny Press. In addition I just purchased Thibaudeau’s new book and it rightfully sits on my shelf between the aforementioned texts, it’s excellent.

James Smith

Peter, those who imply that the distinction between the two different types of hypertrophy is meaningless, are naive.

I would suggest that they petition a middle weight bodybuilder(sarcoplasmic hypertrophy) to challenge a middle weight powerlifter (myofibrillar), or OL weightlifter (myofibrillar) to a squat contest.LOL

There is a BIG difference.

James Smith

I have both of these books in my small although quality library.

To the topic at hand. It was argued that the ideas behind myofribillar and sarcoplasmic hypertrophy distinction are merely theories with no scientific studies to back them up. Can anyone provide a study that has evidence to support the theory?

James, I do agree that there is a big difference between the bodybuilder and powerlifter/weightlifter. However, it was argued that the difference lies in the myogenic tone and the ability to recruit motor units (intramuscular coordination). Any thoughts on this???

I would just like to note that I trying to provide only the arguements presented and not my personal beliefs. So when I say “it was argued”, I’m leaving my personal thoughts out of this.

Thank you for your continued thoughts regarding this topic.


I have no background in the subject so I am not speaking with any knowledge but I would like to establish whether the distinction being made is one that is accepted in mainstream physiology
or whether this is a distinction put forward by some East European
authors and which is now received wisdom by some strength training aurthorities in the West.

James-there may well be body shape differences between a bodybuilder/powerlifter but I am not sure that the comparison actually proves the distinction in types of muscle growth. It seems to me that you would need to demonstrate that the muscle hypertrophy experienced in each individual’s case is qualitatively different not that they look different or that one can lift more than the other. Is there any evidence that this is the case? You may well be right about all this but from an intersted bystanders point of view I am not entirely certain that the case has yet been proved.


Principles, Peter, I will go one by one.

Principles, no, I do not have any scientific studies on hand to reference, however, the practical evidence, with respect to the information in my last post, far outways any theoretical objections. In my view anyway.

Principles, powerlifters and OL lifters (especially 110kg and below) will hands down appear to have more myogenic tone/tonus to their physique than “most” bodybuilders. This is a direct representation of the effects on bodycompostition illicited through different loading parameters. The same goes for intra/intermuscular coordination. The loading parameters utilized by powerlifters/OL lifters yields much greater improvements in myogenic tone and inter/intramuscular coordination, than those used by most bodybuilders.

Peter, you actually answered the problem with respect to strength science, at least here in the states. Mainstream physiology is antiquated and in many cases WRONG! When is the last time you saw an American take the gold in any Olympic strength athlete evnent? Randy Barns (shotput) is the only guy that comes to mind to me.

Acedemia is behind the powercurve, and unfortunately perpetuating the production of mediocre minds. As far as the most prolific and well respected, by those in the know, American strength coach goes, Louie Simmons, he never even went to college. What does that tell you?

The former Soviet Union and Easter Bloc countries, and now China, are the source. Just look at the history of the strength athletes throughout Olympic history (i.e., gymnastics, throwers, bobsleigh, OL lifting, etc.)
The East is hands down the superior.

The evidence to support the different muscular adaptations experienced by the different lifters would be glaringly obvious if muscle biopsies were taken from each different type of lifter. Unfortunately, I have yet to aquire such means to perform this type of research. Yet it has already been done elsewhere. I am sure that Charlie, or Christian Thibaudeau has references to support such research.

James Smith

James-thanks for the time you have taken to set out your views. What you say is all very persuasive but if I may push you a bit further
what evidence is there that hypertrophy actually occurs in the selective and distinct ways proposed? I do not think that it is sufficient to demonstrate that any two individuals following different training regimes are different by muscle biopsies but that the muscle hypertrophy-to the extent it takes place- experienced by two groups each following different training protocols is qualitatively different. Can this be said with any certainty?

I am not particularly interested in maintaining a “pro” or “anti” stance but the concept seems to me to be important and therefore subject to the best scrutiny I can put it under!


Peter, Allow me to hypothesize…my view on the subject is that if biopsies were extracted from the quadriceps of an OL lifter and a bodybuilder, you would find that the myofibrillar wall, of the OL lifter, would be thicker than that of the bodybuilder. Thereby illustrating the hypertrophy of the sarcomeres, in contrast to the non-contractile protein/semi-fluid intracellular sarcoplasm.

Based on this theory, it would be prudent to state that it is in fact the different training protocols that yield different forms of hypertrophy.

Think of a baseball bat. The OL lifter would represent the bat with a very small ,in diameter, hole bored through the longitudinal axis. Whereas the bodybuilder would represent the bat that has a large, in diameter, hole bored through the longitudinal axis.

So in terms of diameter of the myofibril itself, both are comprable. It is the architecture of the myofibril that I am disputing.

However, as I previously stated I do not, at this time, have any hard data to support my theory, only what I have previously read in texts, who’s titles I cannot recall.

Stimulating conversation.

James Smith

James- thanks for your thoughts. I am only interested in firming up my
understanding of the concept and the scientific basis for it (to the extent that it exists) and therefore want to push you as much as I can!

I like the architecture analogy but my problem with your comparison between weighlifter and bodybuilder is that there may be all sorts of genetic and other reasons why their muscle structure would be different.

I have previously talked about comparing groups of individuals but can we say with any certainty that within the same individual muscle hypertrophy, however induced, would be different? i.e not that one training protocol produces more or less hypertrophy or greater strength but that to the extent that it takes place at all, the very structure of the hypertrophy is different.

As I said I am really trying to establish when I discuss such matters if I am talking on then basis of hard science or reasonable speculation.


Peter, pushed me you have.

With respect to your dispute that there may be other factors contributing to differences in fiber development (genetics, etc.) you are incorrect.

Genetics, etc., do not play a role in the development of fibres, only the distribution.

Form follows function.

The following excerpts come from Supertraining (Siff)

“…vastus medialis biopsies reveal that the proportion of FT fibres in field athletes and weigthlifters can be over three times greater than that of marathon runners and 50% greater than that of bodybuilders, cyclists and race walkers. The importance of fast fibres in short duration explosive or maximal strength efforts is underscored by the fact that fast type IIx fibres contract 10 times faster than slow type I fibres.”(pg 58)

“Although research indicates that fibre distribution is strongly determined by genetic factors, it appears as if these differences may also be strongly influenced by the type, intensity and duration of training, as well as th pre-training status of the individual. This becomes particularly evident if the muscle fibrre distribution is compared between weigthlifters and bodybuilders. Weightlifters have a considerably higher proportion of FT fibers, a fact which cannot be explained by the contention that specific genetic types excel at specific sports. Bodybuilders have about 10% fewer FT fibres than untrained subjects, while weightlifters have about 10% more FT fibres. It is apparent that even the specific type of strength training may influence the relative proportions of FT and ST fibres and their hybird sub-types. The difference between weigthlifters and bodybuilders probably lies in the fact that weightlifters usually execute considerably more low repetition, maximal effor, explosive training than bodybuilders, who often use moderate loads slowly to failure.” (pg 58)

“The data shows that the longer and more strenuous the submaximal loading (but not the rapid, near maximal low-repetition loading of Olympic Weightlifting), the less there is sarcomere hypertrophy and the more there is sarcoplasmic hypertrophy. Although increase in load intensity and speeding up of its rate increase promotes overall muscle hypertrophy, it is accompanied by a greater breakdown of muscle fibres and a decrease in the number of contractile structures. The hypertrophied muscle contains fewer sarcoplasmic organelles, myofibrils and mitochondria, so that the increased diameter of the muscle fibres is due largely to and increase in the volume of sarcoplasm.” (pg 67)

So there you have it, explosive near max low rep loading yields myofibrillar hypertrophy, in contrast to longer submaximal loading which yields sarcoplasmic hypertrophy.

As I read on I am coming across more and more information supporting my previous statements, however I have lost the desire to continue typing. I urge you to purchase Supertraining and discover the rest.

I have exhausted myself.


Thanks James. Well argued and persuasive and you deserve a rest from my questionning!


Hey Folks,

I’m new here, thought I’d post my introduction here then reply to this subject since it has fascinated me for so long :slight_smile:

I was refered to your forum on the Supertraining digest, once I started reading your posts I started itching to participate. I have been looking, for years, for a forum that is real “sciency” :slight_smile:

I myself, am not a sprinter or into running, just a recreational weightlifter with passion for muscle physiology and all those interesting type subjects.

I have tried on many forums to get some good talk going on things like sarcoplasmic hypertrophy etc, but cannot coax anyone to ‘get into it’ :slight_smile:

This thead is really great and makes a lot of good points. I too have also thought the theory sounded plausable but was wanting for some evidence. I finally came across a couple studies on Pubmed that point to the phenomena of sarcoplasmic hyertrophy, I’ll guess I’ll just post them and let you guys comment on them :slight_smile:

Best wishes!
(sorry if you have already seen these and they are ‘old news’ )

Muscle ultrastructural characteristics of elite powerlifters and bodybuilders.

MacDougall JD, Sale DG, Elder GC, Sutton JR.

Muscle ultrastructure of a group of subjects possessing extreme hypertrophy was compared with that of a control group which had undergone 6 months of heavy resistance training. Two needle biopsies were taken from triceps brachii of two international calibre powerlifters and five elite bodybuilders. In addition, samples were taken from five healthy volunteers before and after 6 months of training of the elbow extensors. One biopsy was prepared for electron microscopy and analyzed stereologically, and the other was stained for myosin ATPase activity and photographed under the light microscope. Despite large differences in elbow extension strength and arm girth there was no significant difference in fibre areas or percentages of fibre types between the elite group and the trained controls. This suggests that the elite group possessed a greater total number of muscle fibres than the controls did. Mitochondrial volume density of the elite group was similar to that of the control group following training but significantly less (p less than 0.05) than the pretraining control measurements. Myofibrillar volume density was significantly lower and cytoplasmic volume density significantly higher in the elite group than in the trained controls. There was a considerably higher incidence of structural abnormalities including central nuclei and atrophied fibres in the elite group than in the control group, which might possibly have been associated with the use of anabolic steroids by the elite group.
Characteristics of muscle-cellular adaptation to intense physical loads.

Brzank KD, Pieper KS.

We studied the influence of a 5-weeks training program, mainly with intense work-loads in form of explosive power, on the skeletal muscle system in 7 male sports students. Muscle biopsy specimens from m. vastus lateralis were analysed histochemically, biochemically and by means of electron microscopy. After the training of several weeks, a clear hypertrophy of FT-fibres (24%, p less than 0.05) and ST-fibres (20%, p less than 0.05) became evident. The fibre composition was not affected by the training program. The increase of mean cross-sectional areas of muscle fibres was not connected with any shifting of volume proportions of cellular compartments (volume density of mitochondria, myofibrils and sarcoplasm) at ultrastructural level. Only in the peripheric fibre region mitochondrial volume density increased from 5.9 +/- 2.5 to 8.3 +/- 1.2% in tendency. Contrary to endurance athletes and untrained subjects, power athletes show higher values of sarcoplasmic volume density in their muscle fibres. Results will be discussed in connection with specific demands of explosive powerful muscular performances.

Bummer, I guess I was a day late and a dollar short getting in on this subject. :rolleyes:

James, good job with the quotes from supertraining… does supertraining reference the actual research papers where those conclusions are drawn from?

Ron do you have a full copy of the McDougall et al., paper? And if so do they discuss any differences within the elite group between the powerlifters and the bodybuilders?

Rossa, only one of the quotes that I used gave a reference. It was (Andersen et al, 2000). However, Supertraining’s bibliography is enormous, so there are plenty of other references for much of the information presented in the text.

Ron, you will have to forgive me, I burned myself out on this particular thread. You missed the action on this one. Don’t sweat it, there will be a myriad of discussions to come.