Functional Hypertrophy- Fact vs. Fiction

Written by Jason FerruggiaTopics: Training

A lot of people, including myself, used to think that higher rep training developed what is known as non functional hypertrophy. This is also referred to as sarcoplasmic hypertrophy. In simple terms the sarcoplasm has been described as a filler type gooey fluid inside the muscles that really doesn’t contract or produce force. Therefore it’s deemed non-functional because it kinda just sits there and looks pretty. In other words it’s good for bodybuilders, bad for athletes.

Myofibrillar hypertrophy is thought to be real muscle growth. The myofibrils have the ability to contract and produce force therefore your want to increase them in size while avoiding sarcomplasmic hypertrophy at all costs.

When you do this you end up with a big, strong, functional athlete.

Or so the thought process goes.

The reality is that you can’t cause growth of the sarcoplasm without also inducing growth of the myofibrals. If this were the case then you’d simply have to train in the range of 10-20 reps on everything, eat a lot of food and you’d grow significantly bigger without being an ounce stronger.

Theoretically you’d be able to gain twenty pounds yet produce not a single iota more force than you did weighing twenty pounds less. You just be big and puffy and pretty. And I’d assume pretty squishy to the touch.

But the body doesn’t work that way. Any type of strength training, where the loading is heavy enough to induce hypertrophy, will increase the size of the myofibrals and the sarcoplasm simultaneously. You can’t increase one without the other. And no matter how you train the growth of the myofibrils will take place at a faster rate than that of the sarcoplasm.

What’s often mistaken for sarcoplasmic hypertrophy is actually nothing more than an increase in the body’s ability to store glycogen. If you do high volume, bodybuilding style training you will get more efficient at storing glycogen in the muscle. That’s why if you decide to blast a weak bodypart for a few weeks with higher volume training it can often increase in size rather quickly. Size increases of an inch on the upper arms or calves in thirty days aren’t uncommon with this type of protocol.

But what’s stretching the tape measure after only two weeks of high volume training isn’t the increased size of the sarcoplasm. It’s not even the increased size of the myofibrils. Muscle simply can’t grow that quickly. It’s simply increased glycogen storage inside the muscle.

This truly is non functional hypertrophy simply because intracellular fluid can not contract and produce force. So while non functional hypertrophy doesn’t exist in the way most people think, it still kinda does.

The implication for athletes is to avoid higher volume bodybuilding protocols simply because you will end up weighing more but that weight will in the form of fluid that doesn’t produce force and will only slow you down in the same manner of excess bodyfat.

jacked athletes

The Low End Theory
So does that mean that athletes should never train with high reps? Not necessarily. A football player could easily train with sets of ten and gain some size that wouldn’t be non-functional. The key difference, I believe, is to simply avoid getting those skin ripping bodybuilder pumps and using methods like body part splits, ultra high volume, super sets, drop sets, etc.

Just doing 3-5 sets of 8-10 on an inverted row and dip after your low rep push presses isn’t going to turn you into a big puff ball who couldn’t elude his own grandmother in the open field.

When you do that type of bodybuilding workout you are training for increased glycogen storage and that will lead to more weight on the scale in many cases. If you just want to look good on the beach that’s fine. But if you have to run, jump and cut you don’t need those extra few pounds weighing you down.

The reality is that if you had one twin do nothing but ten rep sets for a month and the other do nothing but fives, assuming the same total volume and tonnage, they would probably end up looking pretty similar and have made similar strength gains.

There are three real benefits of low rep training that have nothing to do with myofibrillar or functional hypertrophy.

1)    Low reps don’t make you as sore.
2)    Low reps don’t cause as much overall systemic fatigue as high reps.
3)    The third has to do with rest periods and power output as I’ll explain shortly.

The first two on that list are HUGE for athletes. If you aren’t as sore or fatigued you can train more often in a fresher state!

That means that your speed, agility, conditioning and sport specific work doesn’t have to suffer as much.

Everyone knows the feeling the day after a 10-20 rep squat workout. But if you do three rep squats you don’t have that same feeling. If you do three rep squats with a 5 or 6RM you feel even better.

Test this out on yourself if you’re having a hard time grasping it…

Pick a lower body exercise and an upper body push and pull and train three times per week doing three sets of ten on each of them. Then see how you feel.

The next week use the exact same weight and total reps but do fives. So instead of three sets of ten with 200 pounds you will now do six sets of five with 200 pounds. It’s still thirty total reps with the same exact weight.

functional hypertrophyI can tell you for sure that you will be sorer and more systemically fatigued from the tens than you will from the fives.

The third benefit of doing lower reps in place of higher reps is that lower reps allow you to use lower, more sport specific rest periods (which build in a conditioning component to the workout) and to maintain a higher power output throughout the training session.

For example, if you do sets of ten reps your metabolic and cardiovascular system will be more fatigued than if you did a set of five. And believe it or not, contrary to popular belief, so will your nervous system.

As you get more fatigued in all of these ways your performance will start to drop off significantly from set to set. This will force you to use longer rest periods. And even that sometimes won’t be enough to maintain a high power output throughout the workout.

Power endurance is very important for athletes; often more so than maximal strength. One time, limit strength is very rarely the deciding factor in an athletic contest. It’s usually the ability to repeat that display of strength or power that is much more critical to victory.

I’d rather see you replicate game conditions more closely and do a set of 3-5, where power output is high and you’re staying away from failure, rest 30-45 seconds (never more than 60) and move onto your next set of another exercise (if you were doing straight sets of an exercise instead of alternating sets you would have to rest longer).

That would be a more, I guess you could say, “sport specific” or “functional” way of training.

Besides, training’s supposed to be hard. You’re not supposed to sit around on the leg extension for five minutes between sets. You’re supposed to be working.

For these reasons listed I believe that athletes should keep their average reps lower than those just looking to get big and look pretty. You can still build plenty of size with an average of five or six reps per set. And as long as most of your work is done in the range of 1-6 you can still throw in a few sets in the 7-10 range here and there as well. Just make sure your higher rep work doesn’t account for more than thirty percent of your total volume you’ll be fine.

So that’s how you become a bigger, badder athlete.

Let me know your thoughts below.

PS. For more info check out Renegade Football Strength

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30 Responses to Functional Hypertrophy- Fact vs. Fiction

  1. Tyler May 11, 2011 at 11:49 am #

    I’ve been waiting for a post like this. I’m a former-athlete and I still train like an athlete, but my friends who also lift can’t wrap their heads around my style of training. I can’t wait to show them this. Hopefully hearing it from an outside, non-scientific source will help.

  2. Shaun May 11, 2011 at 12:58 pm #

    Another great post and extremely informative. I just started Wendler’s 5/3/1 and am thinking I will eventually need to lower the weights on the hypertrophy assistance exercises I do after the strength sets. Maybe after a few weeks when I properly adjust my 1RM it’ll even out. For instance, in my last squat day I had about 33/66% volume between strength/assistance, so it’s completely swapped from what you suggest. Then again, it was a day with only 19 total heavy reps vs 5×10 assistance afterwards.

    Thanks again for all the great material you provide free of charge. It’s obvious how passionate you are about the topics you cover.

  3. Rory May 11, 2011 at 1:01 pm #

    Hi Jason,

    Just wondering how this factors into 3XM – I’m a football player doing that program. I know you’re always evolving your opinion – do you now think that doing that set of 12 at the end of each exercise is too high volume for athletes?


    • Jason Ferruggia May 12, 2011 at 11:55 am #

      @Rory: Just lower each rep bracket by two. I’m gonna go back and tweak the program soon. But that change will be enough.

  4. Joe May 11, 2011 at 1:04 pm #

    I’m currently doing your Muscle Gaining Secrets program. I love playing basketball and I weightlift to improve my performance on the court. I typically do three strength workouts in a week and play basketball twice. My legs are often too tired from strength training during games – would it be appropriate to modify Phase 2 of the MGS program to sets of 2, 4, and 6 reps? This should maintain periodization while shortening recovery time, right?

    • Jason Ferruggia May 12, 2011 at 11:56 am #

      @Joe: You could try that. First, I’d just cut one set off of each lower body exercise. If that doesn’t help cut the reps

  5. Raymond- ZenMyFitness May 11, 2011 at 1:07 pm #

    Makes sense but if you going to train and lift over a ‘long time’ how about using both methods to like cyclic (periodisation?) the volume in to develop all around size and strength? or more like off season / on season training?

    • Jason Ferruggia May 12, 2011 at 11:59 am #

      @Raymond- ZenMyFitness: You could do that.

      @Jeremy- You could do your maximal strength exercise with longer rest periods and then shorten the rest up on everything else. That works too.

      @Julio- The current version of MGS has the rest periods I recommend. They are still the same for that program. Basically 60 seconds on everything, a few 45’s here and there and some 2-3 minute breaks on the squats and deadlifts.

      • Julio G. May 12, 2011 at 12:28 pm #

        @Jason Ferruggia: So with the reduced rest periods do we still stick with the 5 to 8 reps of MGS?
        Or should we go for lower than 7 reps as you outline in this post?
        Thanks again

  6. Jeremy May 11, 2011 at 1:57 pm #

    Awesome article and I almost always agree with you:)

    However I have a question on this one. For power endurance couldn’t a person do explosive work with body weight and then focus on max strength work with longer breaks. I guess I am saying that I take much longer breaks with my reps and usually leave one in the tank but not always and my focus is not power endurance on that day but rather on raw max strength. I hope this max sense.


  7. Julio G. May 11, 2011 at 2:48 pm #

    Great post! But this made me think about the differences between strength training for athletes and strength training for others who simply just want to get big, strong and lean.
    At the post you recommend shorter rest periods when strength (low rep) training is done by athletes, but at MGS you supported that longer (2-4 min) rest periods stimulated an increase in testosterone so… for people that do not pursue the strength endurance of athletes you still recommend varying the resting time (at MGS on Intermediate we have 3 min rest between squats while just 60 sec for dips) or should we start increasing the intensity and reduce rest periods?
    Thanks in advance and keep up the hard work (Evolving the way one thinks about training must be hard, just like it was hard for many others here when we first saw you saying that 12 low-rep sets where the best to muscle building).
    This site is a great motivation for all of us (well, at least for me).

  8. Marc May 11, 2011 at 4:35 pm #

    If you aren’t able to do barbell squats, would 5-6 reps be a good rep range for unilateral leg exercises such as split squats?



  9. Aaron May 11, 2011 at 8:32 pm #

    Interesting article. I recently read that most NBA players use high rep weight training workouts for the purpose of building muscle that has endurance as well as strength. However, that philosophy seems to contradict what you’re proposing.

  10. zidan40o0 May 12, 2011 at 12:41 am #

    great article !

    I noticed that when I switched to low rep heavier weight range 5-6 rep , I felt more powerful and I could left heavier the next session within the low rep range , I could also swear that I got bigger , much bigger , and yeah , low rep doesn’t leave you as sore and tired and you feel fresh for the rest of the day.s

  11. Eric May 12, 2011 at 10:19 am #

    Jay, so I’ve wondered this for a while… If you do a specialization program for a weak or lagging body part and hit it with high volume for 4-6 weeks, if increased glycogen storage is primarily responsible for growth, does that growth stick around after you stop the high volume protocol?

    Are they long term gains or is something that increases momentarily then lose some quickly after stopping the high volume training?

  12. Mike May 13, 2011 at 3:52 am #

    Jason, I’m a 53 year old construction forman… I will tell you these rules also apply in my world… Great article…. its all making since now.

  13. Great article. I like to do compound exercises in the low rep range then hit the party muscles with the higher reps.

  14. Carl May 14, 2011 at 2:54 am #


    Thought provoking stuff as always.

    If the goal is power endurance and increasing overall numbers (rather than weight) would you suggest keeping in the low rep bracket and increasing the number of sets even on exercises where you are capable of doing many reps (e.g. dips, if I can do 25 in one good set would you break this down into several sets of 5-8, way short of failure but keep them explosive?)

    I really want to increase numbers on chins and dips but also become more explosive if possible.

    Hope the above makes sense and thanks in advance for any thoughts.

  15. Jeremy Priestner | Art of Lifting May 14, 2011 at 8:11 am #

    Wow. Fantastic post. I have never seen anyone write anything to debunk the sacroplasmic/ myofibrallar hypertrophy controversy. I’ve heard even very experienced strength coaches make the mistake of pidgeon-holing sacroplasmic hypertrophy as completely non-functional. In this post, you do a lot to clear up this misinformation. Thanks for this!


  16. Hussein May 24, 2011 at 3:15 am #

    I’m a non-athlete, in my third year of weight-lifting (using principles from MGS, and I’m currently following your Minimalist Muscle plan doing two exercises 3x per week, “two for the time”). I change up the reps and sets according to Minimalist Muscle.

    Do you think its better that I do the 2 exercises, 3x a week but stick to 9 sets of 3 reps instead of varying the reps and set ranges over the course of 12 weeks? If so, can I stick to that for a year (or more)? Thank you

  17. BJN June 1, 2011 at 12:46 pm #

    Great post and very informative. I prefer to go lower reps but I do add in some finishers that are higher rep.

  18. Matt Council July 16, 2012 at 6:33 pm #

    I’ve been looking for information to support my off season Football training program!!! Thank you so much. But I have one question. Will throwing a 3x 1 minute into a 3-5×5 workout hurt the outcomes?

  19. tim August 12, 2012 at 11:30 am #

    I do weightlifting (no competition, just as a therapy). I’ve experimented with short and long sets. When i did high volume I noticed that recovery cycles were longer and strength decreased on the benchpress (dropped from 350 lbs to 300lbs) because high volume benchpress is wearing out triceps and deltoids so recovery cycles between pectorals and triceps/deltoids are becoming offset because pecs are bigger and recover faster. So I went for shorter sets again, funny thing was that I grew stronger then before with ease after switching between myofibrillar and sarcoplasmic protocols. So my suggestion: switch between them and become stronger!!

  20. aaron July 8, 2013 at 4:00 pm #

    one question if i were to swtich from doing one set of bench pressing and go straight to squating(both 1-3 reps) would that make a difference on my strength gains and over all athletic ability instead of doing 1-3 reps x 10 sets on squating and then doing 1-3 reps x 10 sets on bench press, and of course i mean with 85 90% max weight after 4 -5 set warm up with 30% max weight

  21. aaron July 8, 2013 at 4:03 pm #

    and i mean switching the lift after one set back and fourth(only two lifts though)

  22. Gary August 1, 2013 at 11:06 pm #

    If I am training for basketball should I use 4 sets of 6 reps? What percentage of my 1RM should I use doing 6 rep sets?

  23. Peter November 9, 2013 at 3:06 pm #

    Of course weight lifting regardless rep range develops both kinds of hypertrophy, myofibral and sarcoplasmic BUT what rep range does is emphasizing the kind of hypertrophy that is developing more.

    These are random numbers and percentages –
    if you train at 8-12 reps then let’s say you are working 80% sarcoplasmic and 20% myofibral
    if you train at 5-8 reps then let’s say you are working 50% sarcoplasmic and 50% myofibral
    if you train at 1-4 reps then let’s say you are working 20% sarcoplasmic and 80% myofibral

    If you are doing high reps then you are still getting stronger but not as strong as when you do low reps. If you are doing low reps you are still getting bigger but not as big as when you do high reps.

    Who is bigger, a pro bodybuilder or an Olympic lifter ?
    Who is stronger, a pro bodybuilder or an Olympic lifter ?
    Can Mr. Olympia clean and jerk 500+ pounds?

    Olympic lifters don’t look big but they are incredibly strong and they train at 1-3 rep range exclusively.

    • mk November 22, 2013 at 5:46 pm #

      Does not apply since technique is extremely important for the clean and jerk.

      Also, George Leeman trains mainly with reps in the 10-20 rep range and recommends people do that to get stronger.

  24. mark November 20, 2013 at 12:37 am #

    So how would you apply this to Triathletes? you really don’t want any extra size for that (creates drag in the water, less aero on the bike, and harder on the knees for the run). Would the high cardio volume take care of any hypertrophy concerns?

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