Sarcoplasmic vs myofibrillar hypertrophy, which is ‘better?’
The type of hypertrophy optimal for you depends on your weight-lifting goals.
Both kinds of hypertrophy offer unique benefits both athletically and aesthetically.
What Is Hypertrophy?
Hypertrophy is a term that describes the growth of muscle fibers in response to weight lifting.
Muscles themselves are intricate organs comprised of vast amounts of muscle fibers.
Fibers (muscle cells) are extraordinarily narrow but stretch the entire length of the muscle. To give some perspective, the average adult man has upwards of 200,000 muscle fibers in each bicep. Within each muscle fiber are even smaller components called organelles.
Myofibrils, sarcolemma, mitochondria, and nuclei are some of the more notable muscle fiber organelles.
Weightlifting and other forms of resistance exercise can stimulate hypertrophy under the right conditions.
What Stimulates Hypertrophy?
Exercise-induced muscle damage is the fundamental mechanism behind hypertrophy stimulation.
During high-intensity weight training, the contractile organelles (actin and myosin of the myofibrils) experience strong resistance, causing them to tear.
Micro-tearing also occurs in the cell membrane (sarcolemma).
During post-workout recovery, the body repairs the damaged muscle fibers.
Naturally, the body wants to avoid re-tearing its muscle fibers. So, the repaired fibers get replaced with thicker, stronger, and larger fibers.
Progressive Overload Hypertrophy
Based on the principle discussed above, progressive overload becomes even more intuitive.
Incrementally increasing your workout loads over time as you progress through your program repeatedly stimulates hypertrophy.
Once a muscle is fully-recovered from a workout, it becomes more capable than it previously was.
Because the muscles are more powerful, the previously-used load becomes less challenging.
To ensure the muscle gets sufficiently worked, increasing the load is required. This concept is essential to muscle building.
With an increased load, new micro-tears form, continuing the process.
Not challenging your muscles for an extended period can cause muscular atrophy.
Atrophy is the loss of muscle tissue due to lack of use; and the opposite of hypertrophy.
The human body works in fascinating ways. It will allocate what it thinks is necessary to a given area.
The common phrase ‘move it or lose it;’ is meant to be taken quite literally.
If muscles are underutilized, the body has no reason to signal to build or, in extreme cases, keep them at all.
Someone who suffers a severe injury may experience significant muscular atrophy. For example, someone recovering from ACL reconstruction surgery will notice significantly reduced muscle mass in their affected leg muscles.
To a lesser degree, atrophy can occur due to an extended period of not increasing load. Progressive overload promotes hypertrophy and opposes atrophy.
Training To Failure Hypertrophy
Muscle growth, or hypertrophy, is caused by exercise-induced micro-tears in the muscle fibers.
Micro-tears form due to stress put on the myofibrils and sarcolemma.
These tears cause the body to regenerate more myofibrils through protein synthesis. The new myofibrils are slightly thicker plus more powerful, and there are more of them.
To optimally induce micro-tears in muscle cells, train to failure or near failure. Pushing muscles to failure ensures the generation of micro-tears, which ultimately causes muscle growth, given adequate post-workout recovery. Training to failure has proven to be the most efficient and effective muscle-building method.
For safety, there are some things to consider when training for failure.
First, to prevent injury and ensure the targeted muscle group(s) is/are being targeted, it is imperative to practice proper workout form.
Also, identify the difference between training to failure correctly and overtraining. Yes, challenging the muscles is a required component of muscle growth. Although, pushing yourself past your limits may cause injury and negatively affect hypertrophy.
Beneficial micro-tears may cause muscle soreness, often called DOMS (delayed onset muscle soreness).
DOMS is the soreness felt caused by strenuous exercise 24-48 hours after exercise. It is a common and inevitable side effect of weight lifting.
While DOMS can be a positive sign and indicate micro-tears, too much soreness or long-lasting muscle soreness may indicate overtraining and warrant a decrease in the intensity of your next workout.
Keeping those points in mind, a lessened degree or absence of DOMS does not indicate a ‘bad’ or ‘ineffective’ workout.
Generally, conditioned weight lifters will experience less DOMS due to increased tolerance.
What Is Sarcoplasm?
Sarcoplasm is the water-based organelle found within muscle cells, surrounding the myofibrils, and contained within the sarcolemma.
Sarcoplasm accounts for approximately 9% of muscle fiber volume. It is the cytoplasm of muscle cells.
ATP, phosphagens (e.g., creatine), myoglobin, and glycogen are molecules contained within sarcoplasm.
The compounds contained within sarcoplasm are a necessity for aerobic and anaerobic activity.
What Are Myofibrils?
Myofibrils are the organelles contained within muscle fiber responsible for muscle contraction.
Repeating sections of sarcomeres make up the myofibril.
Sarcomere contains the contractile filament proteins which trigger muscle contraction. The two contractile proteins are; thick filaments (myosin) and thin filaments (actin).
Approximately 80% of muscle fiber volume is occupied by myofibrils.
How Myofibrils Are Found Within An Individual Muscle Fiber?
In the average untrained adult, there are approximately 2000 myofibrils in one muscle fiber.
Although, that number can change through weight lifting and protein synthesis.
Individual myofibril stretch across the entire length of a muscle, as muscle fibers do.
Myofibrils Are Composed Primarily Of...
Repeating sections of sarcomeres that contain the contractile proteins; myosin and actin.
During muscle contraction, the sarcomere compresses (shortens) as myosin pulls the actin in. This process is called a power stroke.
Sarcoplasmic vs Myofibrillar Hypertrophy
Hypertrophy refers to the growth of muscle fibers. There are two types of hypertrophy; myofibrillar and sarcoplasmic.
Sarcoplasmic hypertrophy describes the volumetric increase of sarcoplasmic fluid (sarcoplasm) within muscle fibers.
There is a dispute over the claim that sarcoplasmic hypertrophy is achievable through resistance training.
However, many experts believe training to near failure in the 10-20 rep range stimulates sarcoplasmic hypertrophy.
Myofibrillar hypertrophy refers to the increase of myofibril density within the muscle fibers.
During post-workout recovery following an effective workout, the body repairs damaged muscle fibers.
New myofibrils form via protein synthesis with increased thickness and quantity. This phenomenon is myofibrillar hypertrophy.
To compare the two types of hypertrophy, let us look at the benefits each possesses.
What Are The Benefits of Sarcoplasmic vs Myofibrillar Hypertrophy?
Experts tend to disagree when regarding the effects and significance of sarcoplasmic hypertrophy.
Sarcoplasm is not directly involved with muscle contraction. Therefore, many conclude that heightened amounts of sarcoplasmic fluid would have no performance-related effects.
Contrarily, sarcoplasm does contain the nutrients required for muscular contraction.
So, it is plausible that sarcoplasmic hypertrophy could increase muscular endurance.
It is safe to say that sarcoplasmic hypertrophy does not benefit strength directly, although evidence exists that exercise capacity may increase.
Since sarcoplasmic hypertrophy increases the volume of sarcoplasm, innately, muscles will also grow in size.
Generally speaking, sarcoplasmic hypertrophy requires less recovery time than myofibrillar hypertrophy.
Myofibrillar hypertrophy is the hypertrophy type often referred to as ‘hypertrophy.’ Myofibrillar is addressed more frequently than sarcoplasmic hypertrophy.
Training for myofibrillar hypertrophy causes contractile myofibril proteins to grow in strength and amount.
As a result of the increase in myofibril density within muscle fibers, myofibrillar hypertrophy benefits strength performance and increases muscle mass.
Best Rep Range For Hypertrophy
Pertaining to rep ranges, the finite number of repetitions is not the most critical aspect of hypertrophy training.
Progressive overload, training to failure, time under tension, and practicing form should all occupy a higher priority on your ‘hypertrophy checklist.’
That being true, evidence suggests training in the 6-8 rep range to failure/near failure stimulates both myofibrillar and sarcoplasmic hypertrophy.
Training above this rep range will bias sarcoplasmic, and below will target myofibrillar.
Research indicates that stimulating both types of hypertrophy is the most effective way to build muscle size.
Training for both types of hypertrophy causes an increase in sarcoplasm volume and myofibril density, which is optimal for muscle growth.
Best Rep Range For Sarcoplasmic Hypertrophy?
To specifically target sarcoplasmic hypertrophy, training to near failure in the 10-20rep range is optimal.
Best Rep Range For Myofibrillar Hypertrophy?
Myofibrillar hypertrophy is best stimulated by training to near failure in the 1-5 rep range.
Hypertrophy vs Hyperplasia
In summary, hypertrophy is the term that describes the increase in muscle fiber size.
Hyperplasia is the term referring to an increase in muscle fiber quantity.
Hyperplasia (in this context) has nothing to do with its other meaning, which refers to cancerous tumor growth.
Currently, there is not enough literature on the phenomenon to definitively claim that hyperplasia is achievable through weight lifting. More studies are required.
Does Creatine Affect Hypertrophy?
Creatine positively aids the growth of muscle cells.
Creatine phosphate is stored within muscle cells and used to synthesize ATP (adenosine triphosphate).
ATP is the energy required for muscle contraction. Increased creatine stores allow for more ATP available during intense resistance training.
More ATP increases anaerobic performance and enables muscles to perform more repetitions with the same amount of weight.
The increased muscular capacity leads to enhanced hypertrophy via more optimally working the muscles.
Creatine is a non-essential nutrient. Meaning it is made naturally within the body (in small amounts).
Many athletes and weightlifters take creatine supplementation to improve their performance.
To learn more about creatine and if it is right for you, click here.
Hypertrophy While Cutting
Muscle growth is possible while in a caloric deficit.
Although, honing in on workout efficiency, nutrition, and post-workout recovery is vital to avoid atrophy.
Learn more about building muscle while cutting.
You May Also Be Interested In...
Seriously Strong Training – https://seriouslystrongtraining.com/what-is-sarcoplasmic-myofibrillar-muscle-hypertrophy/increases
Wiley Online Library – https://onlinelibrary.wiley.com/doi/10.1002/mus.10386#:~:text=The
National Library of Medicine – https://pubmed.ncbi.nlm.nih.gov/8107539/
National Library of Medicine – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7372125/
The Muscle PhD – https://themusclephd.com/hypertrophy-vs-hyperplasia/
National Library of Medicine – https://www.ncbi.nlm.nih.gov/books/NBK9961/