Why All Muscle Was Not Created Equal

by Joe DeFranco, Owner, Performance Enhancement Specialist
DeFranco’s Training Systems

Have you ever noticed an athlete in the weight room who is built like Tarzan, yet lifts weights better suited for Jane? Yet, there are other athletes who are every bit as strong and functional as they look. Although an athlete’s genetic make-up is always a factor, the answer to this discrepancy in strength and functionality of the muscle can also be due to the different types of training performed by different athletes. Although two athletes may possess similar physiques, the muscle they have built using their different training methods may not be the same. In other words, all muscular growth was NOT created equal! There are actually two very different types of hypertrophy that can take place within the muscle. Being aware of this helps to answer the question of why some athletes possess superhuman strength and others are “all show, no go.” The two types of hypertrophy to which I am referring are sarcoplasmic and myofibrillar hypertrophy.

Sarcoplasmic Hypertrophy

Sarcoplasmic hypertrophy is an increase in the volume of the non-contractile muscle cell fluid, sarcoplasm. This fluid accounts for 25-30% of the muscle’s size. Although the cross sectional area of the muscle increases, the density of muscle fibers per unit area decreases, and there is no increase in muscular strength (2). This type of hypertrophy is mainly a result of high rep, “bodybuilder-type” training (3).

One of the biggest problems I see with the training of power athletes (football players, baseball players, basketball players, wrestlers and even powerlifters) is too much emphasis on training in the 10 – 15 rep range. This type of training has its place, yet should not be the focal point for these athletes. For example, most football lineman benefit from added bulk to prevent from getting pushed around on the field. “Bodybuilding” methods, using these rep ranges, can be beneficial if incorporated during the season to prevent muscle mass loss, as well as after the season to add bulk, which may have been lost during the season. Also, there is some scientific evidence that states a bigger muscle may have a better chance of becoming a stronger muscle once maximal strength training methods are employed. The key to remember is that this type of hypertrophy has little to do with such explosive movements as hitting, running, throwing, jumping or performing a one-rep max. This is why professional bodybuilders, whose training mainly hypertrophies the Type IIA fibers and causes an increase in the non-contractile components of the muscle (sarcoplasmic volume, capillary density, and mitochondria proliferation) are not the fastest or even the strongest of all athletes. This is despite the fact that they generally have more muscle than any other class of athlete! I consider this type of hypertrophy to be form over function.

Myofibrillar Hypertrophy

Myofibrillar hypertrophy, on the other hand, is an enlargement of the muscle fiber as it gains more myofibrils, which contract and generate tension in the muscle. With this type of hypertrophy, the area density of myofibrils increases and there is a significantly greater ability to exert muscular strength (2). This type of hypertrophy is best accomplished by training with heavy weights for low reps (3).
One must remember that the average football play lasts 4.5 seconds, it takes about 3 seconds to complete a 1 RM, it takes less than a second to swing a bat, less than a second to throw a punch and less than a second to jump for a rebound. As you can see, most athletic activities are explosive in nature. This is why it is imperative for athletes to incorporate maximal strength training methods (1-5 reps), which train the part of the muscle responsible for these explosive contractions, into their routines. Repetitions in the 1-5 rep range, using 85 – 100% of a 1RM, also have the added benefit of training the nervous system – which I feel is the most overlooked component of training the athlete. 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) (1). These training methods also hypertrophy the pure fast twitch fibers – the high-threshold, Type IIB fibers. Incorporating these training methods into your routine at the right time will undoubtedly improve your muscles ability to generate more force and contract maximally during any sporting activity. In essence, myofibrillar hypertrophy is what I would term functional hypertrophy.


Although the human eye cannot tell these two types of hypertrophy apart, the difference will always become quite apparent as soon as it’s time for an athlete to put his/her muscle to use. As athletes and strength professionals, I feel we all have a responsibility to prevent ourselves from getting into the “3 sets of 10” rut. It is our job to educate ourselves, be creative, and put together the most result-producing programs available for our athletes or ourselves. This may mean incorporating both types of hypertrophy training into your routine, depending on your goal and training phase. But remember that no matter how bad those high-rep sets of leg extensions burn, they will never build the strength, power, and functional hypertrophy of a heavy set of squats or deads!


  1. Poliquin, Charles. Modern Trends in Strength Training. Volume 1.
    QFAC Bodybuilding, 2001.
  2. Siff, Mel C. and Yuri V. Verkhoshansky. Supertraining. Colorado: Denver, 1999.
  3. Tsatsouline, Pavel. Power to the People. Dragon Door Publications, Inc., 2000.


  1. Thanks for the article, clear concise and to the point.
  2. David, If you are training for boxing (a weight class sport) I would stick with super low rep ranges (1-5) with heavy compound lifts. Power (strength +speed) is what you want to train for. Look into Hiit training as well. Although endurance is important to. Stick with 1-5 for strength and body weight exercices 30+ reps for endurance. That way you can get strength speed and endurance without unnecessary muscle mass weighing you down. Great article. Very clear and informative. I wish I read this when I first started lifting.
  3. Most of you idiots just need a basic training and diet plan with ANY program. This pertains to athletes and.more advanced weight trainers. Stop asking stupid questions, pick a basic program and stick with it for 6 months. Dont come back here till you have a miniumum of 3 years exp.
  4. Great article. Point I have been trying to make with women training in the gym for years. A woman who doesn't want to BULK UP should be doing a power based workout instead of doing a high rep bodybuilder workout.
  5. For the myofibrillar training with 1-5 reps per set what would be the ideal rest time between sets, sets per exercise, and number of exercises per body part? Also would you recommend alternating between 2 unrelated body parts at the same time (eg chest and biceps ) or would that not allow for adequate recovery between sets?
  6. what is the meaning by rep & RM?
  7. If you train for strength you will eventually get big AND STRONG rather than just big. Could you imagine a 500 lb squatter and 400 lb bench presser not being big?
  8. I believe by starting heavy(after warm up of course)for 2-3 reps with 3-4mins to let the CNS recover, after your "heavys" you can do "lights" I find this works best for power,then size!
  9. Can you tell me how much weight is equal to typing for 1 hour. or can you tell me where to find this answer....thanks for your help.
  10. Can you site any research suggesting that we can increase the number of myofibrils? Or is it more of the fact that we can increase the amount of contractile proteins within the myofibrils (sarcomeres) which are in the muscle fibers?
  11. So what about pyramids? best of both worlds? When I do them on flat bench for example I start with a light 18-20 reps and add the weight on till i get to the 3-5 rep range...uaually takes 6 sets. Also...I know definition is gained through diet but which type of Hypertrophy training would help with the goal of getting cut...
  12. Joe How do you put up with these dumbass comments and questions from these people??????
  13. 3 sets of 6 reps using a very heavy weight seems to be a happy medium, and has done wonders for both my strength and also physique. Certain studies have proved that this type of hypertrophy lasts longer than bodybuilder style hypertrophy. Cleans, Squats, Benchpress, Weighted Dips, Weighted Crunches, Weighted Chins, Bent-Over Row, Deadlift, Overhead Press and Glute Ham Raise are all I do (divided into two workouts - The first one ending in crunches) alternated Tue, Thu and Sat. I really do reccommend this to any experienced lifter who needs something different and wants to improve both strength and pack mass on.
  14. Rycko thanks for answering my question m8 much appreciated! Id really like you to answer both my other comments (by sam) Thanks again!!!
  15. Maxex, Myofibrillar hypertrophy wouldn't be termed such if it didn't mean your muscle get bigger (hypertrophy). Your skeletal muscle adapts to having to push great weights by increasing the size of your individual muscle fibres, rather than increasing the number of muscle fibres present. As such, you will definately get bigger with both types of hypertrophy, probably more so with the sarcoplasmic type, but then again, since myofibrillar hypertrophy involves the actual contratile proteins increasing, you'll keep your 'gains' longer than with the sarcoplasmic type. All hypertrophy involves a mixture of both types, in varying proportions, and isnt isolated to one type.
  16. Last question since type II myofibrillar hypertrophy is not as obvious or as big as sacoplasmic hypertrophy can you still notice monthly increses in myofibrillar hypertrophy or is it not that noticible? Basically I want as much Type II B muscle fibre as I can get! If I eat as much protien and food as a pro body builder and train in 1-3-5 rep range with the prime movers of my sport will I develop large amounts of type II B muscle? Or will type II B myofibrilar hypertrophy always be barely visable compared to type IIA? Thanks mate!
  17. "Also, there is some scientific evidence that states a bigger muscle may have a better chance of becoming a stronger muscle once maximal strength training methods are employed" So if I did 3 months of sacoplasmic hypertrophy followed by 2 months of myofibrillar hypertrophy it would result in greater strength than doing 5 months of myofibrilar only hypertrophy training? Why do bigger muscles have greater potential to become stronger when they are only made bigger in the first place via sacoplasmic hypertrophy? Whats happening to the cells/ muscle fibres when you train previously sacoplasmic muscle with maximal strength training methods? Why do bigger sacoplasmic muscles may have a better chance of becoming a stronger muscle with max strength traing? Whats this new evidence? Thanks again :)
  18. Hi thanks for making it so clear great article!!! So what happens when your sport needs both myofibrillar hypertrophy for strength and power but also endurance Take for example a boxer he has to hit hard / explosively using type II B muscle fibres But he has to do that for 12 rounds so how can those type II B fibres perform this way when they are supposed to fatigue so quickly? ie how is power endurance possible? Or is he actually using the weaker type II A or type I fibres? How does power endurance in sports work? Also they do alot of endurance running does working the slow twitch type I muscle fibres interferre/ convert the type II B mucle fibres into type II A or type I? Thanks!!!
  19. So if I've been working in the ""3 sets of 10"" rut. Should I switch over to lower reps in all exercises or just large muscle groups such as the bench press, squat, leg extensions..?
  20. So if your sport doesn't aquire big muscles. Should an athlete skip/ignore a repetion upper body day?

Add Comment

Copyright 2015
Site by Yellow House Design