The Science of Muscle Building

When it comes to building muscle many people don’t give it much thought. 

Pick up some weights. Lift them repeatedly. Eat chicken or other protein sources. Repeat.

If you practice these simple steps consistently you’ll begin to notice your body changing every time you look in the mirror.

As I was checking out at my local grocery store, the clerk noticed my cart contained organic chicken, a variety of vegetables, and a few other items. The young man posed the question, “I want to get strong. How is muscle built?”

Whether it was his intention or not, he triggered an in-depth question backed by a number of scientific ramifications. 

Few people ever think about the science behind the muscle building process. They simply do what is proven to work and hope the results follow.

The body is an amazing anatomical structure that can change for the better or worse depending upon how you treat it.

The beauty is you can control the variables and your effort can directly be seen in the results. 

In this blog, we’ll take a deep dive into the science behind muscle building. 

How Muscle is Built

Before understanding how muscle building works, it’s important to define what a muscle is.

A muscle is simply a bundle of fibrous tissue in an animal or human that can contract and produce movement in different parts of the body. For the purposes of this article, we’ll exclusively discuss skeletal muscle.

Skeletal muscle is made of myofibrils and sarcomeres that form muscle fibers. When you workout, these muscle fibers are temporarily damaged. Once workouts are completed the muscles begin to repair themselves at a cellular level and the muscle fibers form new muscle protein strands or myofibrils. These myofibrils become thicker and denser over time through a process known as muscle hypertrophy (1).

What most people don’t understand is that muscle growth doesn’t occur while you’re performing resistance training. The mechanisms responsible for building muscle occur while the body is at rest. The growth at a muscular level develops as a hypertrophic response to recovery.

In other words, the body feels like it must expand and grow muscle fibers to prepare for future stressors. But just how do you elicit these types of responses in your body?

Ways to Grow Muscle

If you’ve ever heard of the term progressive overload, it refers to continually putting more stress on the body through different mechanisms. The stress disrupts homeostasis within your body causing muscle to grow as a result.

So what are the main ways of growing muscle? 

Hypertrophy vs. Hyperplasia

If you’ve ever noticed people lifting heavier weights over time, this is to induce muscle growth. By applying greater stress to your muscles over time, certain biological responses occur within the muscles.

Heavier weights trigger mTOR activation and satellite cell activation. Exercise causes metabolic stress, muscle damage, and induced muscle growth as a result (2).

Hypertrophy occurs through an increase in the size of muscle fibers, while hyperplasia is an increase in the number of muscle fibers. For years, people have thought the number of muscle fibers in one’s body was fixed for life and could never be increased.

However, some more recent research has led us to believe adding new fibers is possible through hyperplasia. Animal models have suggested skeletal muscle fibers can be increased through hyperplasia, but further research is needed for human testing (3).

Researchers have identified three primary mechanisms for stimulating muscle growth including: mechanical tension, metabolic stress, and muscle damage.

Mechanical Tension

The mechanical tension placed on muscle has a few components including:

  • Load: the amount of weight on the bar (or dumbbell)
  • Volume: how many reps and/ or sets you complete
  • Time under tension: how fast or slow each rep is completed

More weight + more reps + time under tension = progressive overload. Simple enough right?

Metabolic Stress

Metabolic stress is a physiological process that occurs during exercise in response to low energy leading to metabolite accumulation in muscle cells (4). 

This can be achieved by altering your workout in the following ways: higher reps, partial range of motion, or even static holds. Usually you will experience a burning sensation indicating metabolic stress is occurring.

Muscle Damage

Performing resistance training will cause micro-tears within your muscles and generally occurs during the eccentric portion of the exercise as weight is being lowered. 

Although the vast majority of people do not focus on the eccentric portion of exercises, it can increase the stretch placed under a load causing more muscle damage and eventual growth as a byproduct.

Protein Synthesis

When muscle fibers expand, they need a way to grow. Protein is the building block that makes that happen.

Muscle protein synthesis is a process where the body uses protein to repair muscle damage caused by intense exercise. This process can be enhanced by increasing protein intake following exercise. The amino acids derived in the protein will be sent to the muscles, helping to stimulate muscle growth, recovery, and athletic performance.

The amount of protein varies depending upon who you ask, but most experts recommend consuming at least 0.8g of protein per pound of lean body mass. Ensuring you eat this much protein will give you the best chance at optimal muscle growth and hypertrophy.

Genetics or Effort??

A big component of potential muscle growth is genetic. Certain individuals with better genetics are more adept at building muscle. In fact, about 45% of our muscle fiber makeup can be accounted for through genetic factors (5). 

You can’t control genetics, height, or muscle insertions. Don’t focus on these factors.

Focus on variables within your own control including:

  • Your diet
  • Your workout program (e.g. frequency, duration, etc)
  • Your effort
  • Your consistency

By understanding diet and nutrition you can make proper choices to help reach your genetic potential. 

The young clerk at the grocery store thanked me for my time and said he felt inspired to begin the journey of obtaining the body of his dreams. 

I reiterated, “Rome wasn’t built in a day. Stay consistent, week by week, month by month, year by year, and the results will take care of themselves.”

Nine months later he sent me an instant message on social media showing me his body transformation.

“Sean I don’t know how much muscle I’ve put on, but I know it’s a lot! The great part is that I don’t care because I look good and feel even better! I’ve even got my little brother in the gym now too!”

Building a strong, muscular physique can be done regardless of other external factors. A decent workout program combined with a well-rounded diet will put you ahead of 98% of the population in terms of health, body appearance, and overall well-being.

If you have any other questions about building muscle or are looking for other ways of improving your physique, don’t hesitate to reach out to me. I’m here to support you and your journey towards greatness.

Kindest regards,

Sean Torbati










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