Not All Muscle Growth is Created Equally

Who said all muscle growth is created equally?

Research has shown that not all muscle growth is equal.  The type of growth a muscle sees is directly related to the type of stimulus a muscle gets during weight training. So I thought we’d take a look at the growth in muscle tissue stimulated by conventional training versus static contraction training and see what differences there are.

Before we talk about stimulating muscle growth, we need to understand the anatomy of a muscle.

Here is a diagram that shows how a muscle is arranged (courtesy of Wikipedia):

Muscle cell

This diagram shows you that the basic contractile unit inside a muscle cell is the myofibril. Actin and myosin fibers make up a myofibril. These fibers overlap one another and, when a stimulus is received from the nervous system, act together to cause the myofibril to contract. As the individual myofibrils contract, it causes the whole muscle to contract and shorten. The more myofibrils there are in a muscle, the more force is produced from their contraction.

Myofibrils are bundled together to form muscle fibers. The individual muscle fibers are bundled together to form a muscle.

The diagram also shows you the space surrounding the myofibrils is called sarcoplasm. Sarcoplasm is basically the cytoplasm, or cellular fluid, surrounding the myofibrils and contains enzymes, non contractile proteins and cellular machinery needed for the muscle to produce the energy for contraction. However, these proteins do not contribute to the production of force.

When you train using static contraction, you stimulate myofibril growth. The number of myofibrils in each muscle fiber will grow as an adaptation to the stimulus provided by a static hold. Ask the muscle to generate more force to lift the heaviest weight possible that it can lift and it will adapt by generating more myofibrils which will help it contract with more force. This is called myofibril hypertrophy. The reason muscles have this adaptive response simply has to do with the intensity of the contraction. Think of it this way. A suntan is a way for the body to adapt to sun exposure. You go out in the sun during the wintertime and the summertime but usually you get a suntan during the summertime? Why? Because the intensity of the sun is greater during the summer than it is in the winter. This causes the body to create melanin (suntan) to counteract this intensity. Well, during a static contraction workout, the intensity of the lift is greater than during a conventional workout and hence the body adapts by building up myofibrils to better adapt to this intensity.

As the number of myofibrils increase in each muscle fiber, so does the diameter of the muscle fiber. As the diameter of each muscle fibers increase, so does the diameter of the whole muscle itself. Hence by training using static contraction, you develop strong, dense muscle with more force generating myofibrils.

Conventional training on the other hand stimulates a different type of muscle growth. During the course of a conventional workout set your muscle is under tension for much longer than the 5 seconds used in static contraction. We all know that the longer a workout goes, the lower the intensity. What this stimulus triggers is a different energy system to supply energy for the muscle to contract. Without going into great detail on muscle energy systems, this energy system requires more enzymes to generate an energy molecule that the muscle uses during the contraction. The stimulus your muscle gets from the conventional contraction hence triggers your body to improve these energy systems. As I mentioned above, the sarcoplasm surrounding the myofibril is full of enzymes, non contractile proteins and cellular machinery that provides energy to the muscles. To adapt to a conventional lift where more energy is needed to complete the set, the body builds more of these enzymes, proteins and machinery in the sarcoplasm. The result is sarcoplasmic hypertrophy which is a growth of the sarcoplasm surrounding the muscle fiber. While this growth does result in an increase in muscle diameter, it does nothing for increasing the force production that the muscle can generate.

We’ve now looked at two different types of muscle growth that a muscle can undergo depending on the stimulus it receives. So which type of muscle growth is better? Stay tuned for that discussion…..

Want To Know What Works In The Gym?
Get Workout Variations Revealed - FREE!
1-Set? 2-Sets? 3-Sets? Strip sets? Pyramid sets? Fixed sets? Timed sets? What delivers the highest intensity?

45 Responses to Not All Muscle Growth is Created Equally

  1. Tom Strong at #

    Thanks for the great article Greg!

    I had read about muscle growth while studying for my personal training courses and understand the terms that you are using; but this really shows the difference between SCT and the lower intensity training!

  2. charlie sanders at #

    i’d like both types, and please do get into the muscle energy systems…this seems sensible based on what i remember about muscles. fast twitch slow twitch anaerobic etc.
    this stuff is all so interesting maybe we should do a full blast attempt and then later do a longer hold to challenge changes in the sarcoplasmonicus.

  3. John Stephan at #

    That was mind blowing Pete,

    I believe it explains the difference in appearance and strength of different athletes ie bodybuilders vs strength athletes such as those who participate in the Worlds Strongest Man competitions.
    I have never read any articles on these two kinds of growth prior to yours. So I applaud your knowledge here.


  4. Tom, there is a lot more here but I wanted to start with the basics. I will elaborate more as we go along and the whole puzzle will begin to fall into place!

  5. Charlie, just stay tuned and I will explain it all to you. I’ve got lots of things up my sleeves. That’s why Pete has me around 😉

  6. John, I’ve only given you a part of the picture. The rest of it will come in the near future. The more and more you learn, the more and more things make sense and the more and more you’ll see the brilliance behind SCT!!

  7. Jon at #

    Its all about intensity and conyinued gradual increase in the amount of weight lifted right Greg?

  8. That’s right Jon. Subject the muscles to a stimulus, give it time to rest and adapt to the stimulus, then stimulate again with something more intense than the time before to get it to continue growing further.

  9. Thanks, John, but I didn’t write it. Greg has the deep physiology knowledge. I just stand around with a clipboard and measure everything I possibly can. Haha.

  10. charlie sanders at #

    i hope greg plans to bring it on the research cred. for these concepts…and one funny aspect of muscular effort is that we really have to learn to let go, since when muscle is relaxed it is because of the upper motor neuron blocking the full contraction by the lower motor neuron…so volitional effort is coming from not inhibiting or letting go. to me that explains the ‘learning curve’ and how fear holds us back…also i hope that the simple answer is to do a static hold hard as you can and later do one at some percent of that max for as long as you can for endurance…

  11. Phil at #


    That explanation was just fantastic.
    Although we who have trained with SCT know already how good the method is, we’ve not known why. Your great article starts the process of illuminating people who need more “why”. I’ve always wanted to know why SCT works so well, so differently, has so much more positive body feedback via the results that I still get after 8+ years.
    Keep up the great work,


  12. frank at #

    Hi Greg,
    Your article is truly food for thought. It raises alot of questions. I can hear everyones brain spinning right now, even my own. Can’t wait to hear more on the subject.

  13. Rama at #

    Greg, I am just wondering. Would the muscle growth that happen in conventional workouts also be the same for PFT workouts?

  14. frank at #

    Hey Greg, Frank again!
    While we have you on today, I would like to switch subjects for just a second. Have a question I have been wanting to ask you. Now I know Sct suggest using slow cardio in between workouts to lose fat without compromising recover from Sct. But I’m in the end of a cutting cycle with just about about 4% body fat to go and usually have a tough time from here every yr. But in the last 4 weeks have switch to interval forms of cardio and the fats just falling off. Actually had to add food and cut down on the intensity of interval training because I was losing too fast. Recovery for Sct needs a little more time in between workouts this way, but I know alot of people here want to get stronger and build size with Sct but also want to lose fat! Any thoughts on this subject would be helpful.

  15. John at #

    Sorry guys,

    I didn’t catch that it was Greg who wrote the piece.
    I am quite excited about the information in this thread.

  16. Rama, before I answer that question, I need to explain more about energy systems. That is coming up. Once I explain how the energy systems in muscles work, I’m sure you’ll be able to answer that question for yourself.

  17. My thought on the subject is KEEP GOING!!! Measure your weight and body fat periodically to make sure you’re not losing muscle but my guess is that you’ll find that most of the weight loss is from fat while lean tissue either stays constant or increases. This is the holy grail of fitness training so don’t stop unless you see big losses in lean tissue. This has been my training protocol for years now and it helps me maintain body fat under 6% year round. Congratulations Frank, you’ve found the holy grail of efficient training!

  18. frank at #

    Thanks for the kind words Greg! I believe that Pete’s system of SCT and Power Facter is the best weight training I’ve ever followed. Pure genius! I hurt my shoulder a month ago and could not weight train. Thought it might be a great time to reavaluate my cardio and diet. Now I’m not here to push another trainers system, but I have to give Darin Steen, a trainer in Chicago the credit who started me doing interval training and an unusally way to cycle carbs to lose fat. You eat fruits and vegetable carbs one day and starchy type carbs the next and repeat. His fat loss sytem and Pete’s training is an unbeatable combination. Two Great Trainers !!

  19. Bob at #

    That is interesting,as Frank stated about brains spinning.I know mine is.looking forward to the next part of the article…

  20. Donnie Hunt at #

    The whole thing about volitional effort makes sense to me. Being able to exert maximally, not having to consciously maintain a position. Being able to push with all your might. What if the level of resistance was at a level that prevents you from staying in the intended position from the get go. Would this present an even higher form of intensity? Again this is not my idea.

  21. We might have a secret weapon in this area. A couple of years ago I met with some folks in Silicon Valley where they demonstrated and allowed me to experience a possible method to facilitate peak performance for the brief period necessary for a static contraction. I don’t mean to be vague but non-disclosure was required and the conditions were near-secret for testing. We need to test it with SCT subjects but if it works it will be unbelievably cool and a huge step forward.

  22. Donnie Hunt at #

    Sounds really cool Pete! I know you guys and some others have really got me thinking in some different directions about the whole strength training realm. Good stuff!

  23. Donnie, that’s the whole point. If you follow what the majority are doing, you will get the results that they are, which aren’t very promising. This is a new way of thinking for the 21st century. We’re going to make strength training evolve in the future!

  24. Donnie Hunt at #

    This is a really good point here John.

  25. Bob at #

    Greg, Great article….my question is: What is the best way to develop fast twitch muscle fiber? Does static contraction vs. conventional training have a different effect on explosive speed in muscles.? Do quick accelerated reps in conventional training work better for explosive strength?

  26. John at #

    To expound on my comment I believe what Greg has revealed could explain the reason why there is a markedly different appearance in how weight trained athletes appear in the different disciplines i.e. bodybuilding vs power lifting.

    For example if you compare the physique of Arnold Schwarzenegger in his prime to Bill Kazmaier’s in his prime there is a tremendous difference. Bill Kazmaier who displayed prodigious feats of strength did not have the bulging muscle bellies that Arnold displayed and yet he outweighed Arnold by a 100 pounds and possessed the power to toss Arnold around like a rag doll.

    Kazmaier by contrast would have looked ridiculous in posing trunks performing a posing routine on a bodybuilding stage regardless of how ripped he was. Arnold’s training regiment was comprised of a lot of reps and sets performed 6 days a week, twice a day! Kazmaier on the other hand performed low reps with extremely heavy weight. I don’t think it takes a Philadelphia lawyer to realize who had the higher concentrations of saroplasm in their muscles.

    Aside from genetics I believe the type of training each performed contributed largely to the appearance of their respective physiques. From reading what Greg posted here there is no doubt in my mind that Kazmaier’s muscles were very dense and powerful but I suspect Arnold’s muscles which were definitely not weak contained more sarcoplasm surrounding the his muscle fibers than did Kazmaier.

    I can’t wait to read what Greg has in store for us in his follow up to this very interesting subject.

    All the best,

  27. Shane at #

    Hey Greg, I wanted to also ask you how to best develop our fast twitch muscles. I have been using static since last October and have seen incredible gains in both strength and size. And I was hoping that you could tell me how to incorporate static into this workout. I want to thank you and Pete for all of your research and dedication into the most efficient strength training i have ever found. I look forward to hearing back from you. Keep up the amazing work.

  28. charlie sanders at #

    from what i remember acceleration multiplies force and that increases injury risk. also, please remember to isolate skill development from strength training. skills are specific and should be practiced exactly as they will be done. i think of explosive reps as a skill.

    your fast twitch fibers are the more powerful fibers as well as the bulkier fibers, this is why we do SCT; to skip trying to fatigue slow twitch and intermediate fibers and jump straight to overwhelm, thus stimulating the CNS to create change.

  29. Shane, by doing static contraction training, you are activating the fast twitch muscle fibers. They are the muscle fibers that generate the most force and fatigue easily. Continue on with your training and you will see performance improve as a result of the training focusing on these muscle fibers. I’ve noticed it in my martial arts and I’m sure you will notice it too if you’re involved with any sports or activities that use these fibers.

  30. That’s why I love SCT. It allows me minimal time in the gym to train the muscle fibers that I will use in my martial arts. The time I save I then use in actual MMA training which is where my skill develops. Same thing can be said of any sport. SCT saves gym time which can be used for skill development time!

  31. John at #

    Very true Greg,

    I would like to add that explosive training when it comes to resistance exercise invariably will cause your joints to literally explode, the forces that are generated on the joint and its connective tissue go up exponentially due to the tremendous momentum leaving very little in the way of actually stimulating muscle growth. Folks what we are after here is achieving a maximal muscular contraction using the heaviest weight performed in the safest possible range. SCT satisfies this in every respect.

    When you train explosively momentum removes the stress from the muscle and places it directly onto the joints and your skeleton. If you want to subject your body to EXPLOSIVE training you will not be doing for very long. Lets take care of our bodies not put them through a demolition derby.


  32. And not just time. It save recovery resources too. So more sport-specific training can be done before hitting the overtraining wall.

  33. Bob Tillberg at #

    Thank you for all of your imput to my question. That makes perfectly good sense to me. I work with athletes that focus primarily on getting faster, quicker and their agility skills. Can’t wait to see how SCT will enhance their speed. Anything you can suggest for specific exercises for speed development?

  34. Shane at #

    Greg, thanks for responding so quickly to my question. I was suprised to see something the next day. I will continue with ur advice and continue to annoy the personal trainers n the gym by not doing full reps. Lol. It drives them crazy that we r making the gains in both size and strength without doing full reps. They tell us its impossible and we laugh every time we take our new measurements. Thanks again for ur research.

  35. Tom Strong at #

    Hi Shane,

    I don’t spent much time in the weight room anymore, but when I do the personal trainers seem to be pretty impressed with a skinny guy like me putting that much weight on the bars! Some of the guys that I used to see three days a week are pretty impressed also – but not enough to try it!

  36. Shane, one day those trainers will see the light and will be teaching their clients that static contraction is the best way to train. When that day comes, you can walk up to them and tell them “I told you so.” I’ve developed a personal training business model to go along with SCT so those who get certified through us can use that business model to help them make money.

  37. Brian at #

    @ Shane: I want to piggyback on this thread. I mentioned in a previously article that I had been doing partials and SCT during the winter (since December). When it came to
    swim season (I only swim outdoors in the ocean) I was shocked at how much strength transferred to my crawl. And, I did not do any swimming whatsoever for about 6 months. The power in my upper body and legs was unprecedented from previous years. Swimming is pretty much a strong range of motion sport so the fit was perfect.

  38. Tom Strong at #

    Agreed Brian;

    I don’t swim in the ocean but I do have a pool with swim jets which I started swimming in as the weather has warmed up. I also have noticed that I swim longer with the crawl!

  39. Stuart at #

    Excellent article Greg.I read SCT back in 2001 and just stumbled upon this site a few weeks ago. This site and the research you and Pete have been doing is revolutionary!
    I will be using SCT and PFT from here on out!

  40. steven at #

    Hello Greg,

    I’m interested in the SCT personal training certification and would like some more information. Would you email me or provide a link? Thanks.

  41. Matt at #

    This article is one of my favourites on the whole site, any chance a follow-up article is on its way?

  42. Matt at #

    Hi Pete,

    the last paragraph:
    “So which type of muscle growth is better? Stay tuned for that discussion…..”

    Basically, the scientific content is great, and this article is full of it – I learnt a lot.

    Some additional info that wasn’t in this article, which I learnt over time:
    * Sarcoplasm accounts for 25-30% of a muscle’s size
    * Some of the many benefits of training the nervous system are: increased neural drive to the muscle, increased synchronization of motor units, increased activation of the contractile apparatus, and decreased inhibition by the protective mechanisms of the muscle (golgi tendon organ)
    * There are two techniques that achieve the objective of myofibrillar hypertrophy. The first and probably the most popular is the use of many heavy sets with few repetitions (80 to 100% of 1RM). The second technique is the use of timed sets. Timed sets are done by choosing a timeframe and performing as many repetitions as possible in that timeframe. This ensures that each repetition is done in an explosive manner and this way only myofibrillar hypertrophy is achieved. The advantage of this technique is that it enables the athlete to train the right type of fibre and work on the specific energy system at the same time. It allows athletes to develop physical capacities directly applicable to their sport. For example: the average play, point or shift of a given sport is 30 seconds; these examples give a perfect timeframe for specific training. Timed sets are very well suited for power, power endurance and muscular endurance and myofibrillar hypertrophy. Their weakness is in strength development. It is recommended to combine timed sets with heavier weight training for strength results and performance levels to be optimal.

    So I conclude that strength is a combination of the number of myofibrils and neural-related aspects. SCT will train both of them. Whereas PFT training is less neural and more of a combination of myofibrils and sarcoplasm. I expect PFT (with the correct refinement of workout duration) will be optimal for muscle size, but not peak strength which is where SCT comes in.

    I want both. So when I train my chest, I do a peak lift which should be training my neural pathways and testing my myofibrils. The warm up and progression to the peak lift is a very effective warm-up for what comes next. Then I do a 2 minute PFT workout, which should also be demanding the sarcoplasm reservoirs (I know that I have to stop for a few 5 second rests in that 2 minute routine so I suspect this is due to sarcoplasm).

  43. Matt, you are on the right path here. Keep doing what you’re doing. I’ll put it as simply as that. You’re right, there was A LOT more that could have been written but then I was worried that I’d lose most of the readers. I tried to keep it short and simple. There will be a time when we will elaborate on this topic a lot more. Let me know how the results turn out.

  44. Matt at #

    Greg, the results are great. These are my workouts for benchpress:

    Workout 1: 160kg peak, and then 57 reps of 90kg in 2 mins
    Workout 2 (7 days rest): 170kg peak, and then 57 reps of 100kg in 2 mins
    Workout 3 (7 days rest): 180kg peak, and then 40 reps of 110kg in 2 mins
    Workout 4 (7 days rest): 185kg peak, and then 56 reps of 100kg
    Workout 5 (10 days rest): 190kg peak, and then 68 reps of 100kg
    Workout 6 (12days rest): 190kg peak, and then 51 reps of 110kg
    Workout 7 (15 days rest): 195kg peak, and then 56 reps of 105kg
    Workout 8 (15 days rest): 200kg peak, and then 61 reps of 105kg
    Workout 9 (20 days rest): 205kg peak, and then 77 reps of 105kg

  45. Matt, looks like you’ve got some good progress there. I’d say keep going! Great job!