Even without knowing in detail about the types of muscle growth, you have probably seen different muscular developments.
Powerlifters for example, have that rugged, bulky look on their frame. They are massive and strong, even in a shirt. They are not shredded for the most part, but look pretty powerful overall.
On the other hand, we have the strictly bodybuilding-oriented trainees, who look for optimal size, combined with visible muscle separations, fibers and detail. Those are also the exact people who often look like non-trainees in regular sized shirts.
And while fat plays a major role in how the musculature is going to look, there is another factor- The predominant type of muscle hypertrophy.
We all know that resistance training, if, of course, combined with proper nutrition and recovery windows, leads to muscle growth, or in other words – Hypertrophy.
Hypertrophy is a result of a previously unknown stress, which the musculature has gone through and adapted to.
Types of muscle tissues
“Skeletal muscle fibers are broadly classified as “slow-twitch” (type 1) and “fast-twitch” (type 2)
Type I fibers have low ATPase activity (at pH 9.4), are slow twitch, have high oxidative and low glycolytic capacity, and are relatively resistant to fatigue. Type IIA fibers have high myosin ATPase activity (pH 9.4), are fast twitch, have high oxidative and glycolytic capacity, and are relatively resistant to fatigue. US National library of medicine” 1
Each muscle consists of two types of muscle fibers- Slow-twitch muscle fibers and fast-twitch muscle fibers.
Needless to say, the size of the musculature is directly related to the size of the muscle fibers and when you stimulate their growth, muscle gains will occur.
So, the two types of muscle fibers are
Slow muscle fibers
These muscle fibers are not particularly strong, but they are extremely durable and can sustain physical activities that are long in duration.
These fibers are surrounded by blood vessels, which allows them to be consistently oxidized, making them more resistant to fatigue and exhaustion.
Fast-twitch muscle fibers
These are the exact opposite of the first type. Fast twitch fibers are extremely powerful, but get exhausted relatively quickly.
As we mentioned, slow fibers are used for low intensity activities that are long in duration, while fast fibers are used for intense, short-burst movements.
Now that we know this, we can move on to the types of muscle growth.
The types of hypertrophy
Generally, there are two types of muscle hypertrophy
- Myofibril muscle hypertrophy
- Sarcoplasmic muscle hypertrophy
The myofibrils are essentially the units of muscle cells, otherwise known as “muscle fibers”.
Myofibril hypertrophy is the most sought-after type of hypertrophy by strength athletes like powerlifters, weightlifters and other sports, where an increase in bodyweight is not the predominant focus of the athletes.
The main function of myofibril hypertrophy is an increase in the maximum strength capabilities of the individual, as the myofibrils (muscle fibers) have an essential role in muscle contraction.
Generally, such hypertrophy is achieved in the 3-5 repetitions range at very high levels of intensity- 80%+ of maximum strength capabilities
During such training that prioritizes this type of hypertrophy, we observe micro-trauma of the fibers, which, after the workout, starts recovering, then reaches a state of hyper-recovery and grows, if stimulated within the hyper-recovery window.
“In essence, a biological effort to repair or replace damaged muscle fibers begins with the satellite cells fusing together and to the muscle's fibers, often leading to increases in muscle fiber cross-sectional area or hypertrophy. The satellite cells have only one nucleus and can replicate by dividing. As the satellite cells multiply, some remain as organelles on the muscle fiber whereas the majority differentiate (the process cells undergo as they mature into normal cells) and fuse to muscle fibers to form new muscle protein stands (or myofibrils) and/or repair damaged fibers… Young sub Kwon, M.S and Len Kravitz Ph.D” 2
This type of hypertrophy is also referred to as “Energetic hypertrophy”, as it is a result of the depletion of energetic structures in the sarcoplasm of the muscle cells.
The sarcoplasm is essentially the jelly-like fluid surrounding muscle cells.
The energetic hypertrophy is mostly looked for by bodybuilding-oriented athletes, who prioritize the overall harmonic look of the physique.
If that is our main goal, we should be well aware that this approach to training will lead to less strength gains, as opposed to myofibril-oriented development.
To achieve sarcoplasmic hypertrophy, we train with fairly lower intensity- 65~80% with repetitions varying from 8 to 15, depending on the size of the muscle group, with the lower body taking the biggest toll and highest number of repetitions.
“With muscle hypertrophy at the cellular level in humans, the actin and myosin contractile proteins increase in size and number (Schoenfeld 2010). In addition, Schoenfeld adds there is an increase in the fluid (sarcoplasm) and the non-contractile connective tissues interspersed within muscle, a concept collectively referred to as sarcoplasmic hypertrophy. Aaron Bubbico and Len Kravitz, Ph.D.” 3
You should however, include both types of training in your regimen.. But..
Set your priorities right!
This article gives you pretty practical advice, however, you should kill your ego and come to terms with your goals.
Know what you want to achieve. Do you care more about maximum strength development?
Or would you prefer a nasty, shredded physique that screams sarcoplasmic development?
Whatever your case is, do not exclude any of both. Just use this information and prioritize the type of training related to your main goal.
A different factor for muscle growth
Intensity, volume and density and their ratios are crucial for gains, however, there is a fourth training parameter, often overlooked by trainees – Constant tension!
In the beginning of your training career, you might not notice it.
You go into the gym, train however you like, without having a strict approach to exercise execution, and you still grow!
That is often referred to as “newbie gains”. After a while however, you need to start paying attention to the amount of tension your muscles get during each repetition.
Generally, constant tension is realized through lower levels of intensity, and even though that means less weight, the pros of using this method are substantial.
Utilizing the constant tension principle, we can control the trained muscle and therefore achieve a better peak contraction and mind-muscle connection, as opposed to the quick-pace, explosive movements, where the intensity of muscle contractions and retractions alternate.
This control of the working musculature leads to better depletion of the energetic reserves of the muscle and therefore, the hypertrophy stimulus is greater.
On top of that, the pump is way better and you pretty much feel like you’re in complete control of each muscle fiber.
As a whole, we should not strive to increase intensity and the weight on the bar/of the dumbbells all the time, as there is a certain threshold, especially for beginners.
Your best bet, whether you are a beginner or an intermediate/advanced trainee is to slowly change your training parameters and demand more of your musculature, while parallel to that, you try to keep your exercise execution as strict as possible.
It is a good idea to know that the skeletal-muscle and nerve apparatus are pretty delicate, and if systematically overloaded, you can experience some pretty bad reverse effects, such as injuries, exhaustion and a feeling of a total burnout, rather than consistent progress.
Paying attention to other factors, such as nutrition, hydration and proper rest is just as important as training itself.
These factors should be well tailored to your individual characteristics, goals, activity levels and exercise output, to help you optimally recover and re-fuel before each workout.
Read follow guide: Beginner cardiovascular training here