Muscle Growth and the Science Behind It

What exactly does the word “anabolic” imply? What are the meanings of words like “muscle protein synthesis” and “hypertrophy”? What causes muscles to develop, and why is muscle building important?
We need to get this straightened out. Muscle isn’t just the body’s show-off organ; it’s also important for our health, survival, and metabolism. Even if you don’t want to get meaty thighs and boulder shoulders, adding a lean body mass will help your body in different ways. Understanding the fundamentals of muscle development will help you distinguish between reality and pseudoscience, and wise decisions from time wasters.

Muscle Growth Mechanics

You contract thousands of small muscle fibers as you flex your bicep (and the science isn’t straightforward about whether you have to do it in front of a mirror or not). Each of those fibers is a muscle cell, which is made up of thousands of sarcomeres, or “links.” The chain reaction that flexes your guns begins here when our brain sends a signal to shift. There are also tinier “contractile fibers” called actin and myosin within each sarcomere. This is where the muscle-building magic happens.

Muscle development (or “skeletal muscle hypertrophy,” as it’s known at science parties) is the product of a complex mechanism in which each muscle fiber receives more myosin “filaments.” Over time, this makes the cell’s “engine” bigger and stronger.

Building a bigger engine, on the other hand, isn’t easy, and your muscles won’t be able to do it alone. It needs two components (protein) and a mechanic (mTOR).

The acronym mTOR stands for “mammalian target of rapamycin,” which explains why we use the abbreviation. It’s a complex protein that controls when and how much muscle your body builds. When you lift weights, you activate mTOR (the mechanic), allowing him to get to work. Muscle protein synthesis, or MPS, is the name for this method.

Life would be very straightforward if that was all there was to it. All we’d have to do is lift some weights and wait for mTOR to do his thing, and we’d be bursting at the seams with muscle. Unfortunately, MPS has an evil counterpart in the form of muscle protein degradation, which works in direct opposition to it.

You don’t gain or lose muscle while these two powers are in equilibrium. If your “protein balance” is positive, the surplus can be guided into muscle cells (via resistance training). However, there is no fuel for the engine and no parts to make it bigger if you have a negative or neutral protein balance. So, if you want to add muscle, you’ll have to push your body into a net protein balance. MPS then gains the upper hand.

In bro-science, this is referred to as “being anabolic,” which refers to the condition of the body’s building tissues as opposed to the evil “catabolic,” which tears it down and causes you to lose your gains.

However, there’s a bit more to it.

Your body is never completely anabolic or catabolic, and you’ll always have some muscle synthesis and breakdown going on no matter what you do. And what we consider to be “good” for muscle development, such as resistance training, can be both anabolic and catabolic. It’s essential that the sum of those results is positive (muscle gain) rather than neutral or negative. And, much like counting macros, your long-term performance is measured by what you do on a regular, weekly, and monthly basis.

Positive Protein Balance: Tipping the Scales

So, how do you tip the scales in your favor in terms of synthesis and breakdown?

If you’ve scoured magazines for any muscle-building trick, you might think this part is difficult: drink a protein shake before and after your workout, take BCAAs when lifting, use short rest times, train to exhaustion, do high reps… The problem is that most of the things on which people spend their time and energy are insignificant, or worse, do not benefit them at all.

The science can be complicated, but the fundamentals are simple: exercise hard and eat plenty of protein.

When you lift weights, you’re increasing the breakdown of muscle protein. However, when you recover, the pendulum swings back in your favor, and mTOR kicks in. Lifting weights causes three forms of stress to muscle fibers that signal them to grow: mechanical tension (also known as “volume”), metabolic stress (also known as “the burn” and caused by lowering the pH in working muscles), and muscle damage. Although some old-school bodybuilders believe that muscle damage is essential for development, science does not support this. What we do know is that volume (tension) is the most important factor in muscle development. You will continue to make improvements by steadily increasing volume (in the form of weight, reps, or sets).

Simply put, muscle is created by lifting weights and working out hard.

Then there’s protein, which is the other half of the equation. The engine of mTOR needs parts, and those parts are critical amino acids. You must obtain these from your diet because your body cannot synthesize them on its own. Some proteins, such as leucine, are particularly relevant because they stimulate MPS directly. If you get the majority of your protein from high-quality sources like meats, dairy, and eggs, you’re likely getting enough of the necessary nutrients you need to gain muscle.

How much protein do you drink on a daily basis? It varies by person, but a daily intake of 1.4–2 grams of protein per kilogram of body weight is a good place to start. If you weigh 150 pounds, you can consume 95 to 136 grams of protein per day.

So now you know the “secrets” to increasing mTOR activity: eat protein and exercise.

Is this, though, all that matters? Do other factors influence how much muscle you can gain or how easily you can gain it? Let’s take a look at the muscle-related FAQs one by one:

Will you risk all of your hard-won gains if you don’t drink a protein shake right after your workout? No way! It’s unclear how critical protein timing is, but we do know it’s not necessary. Total daily protein is much more important, so that’s one less thing to worry about.

What about BCAAs, for example? The response is the same. BCAAs are delicious, but they aren’t magical. They’re really only three of the necessary amino acids that you get from high-quality, protein-dense foods like meat, dairy, and eggs! (And if you’re still buying whey protein supplements, you’re getting BCAAs.) Let’s just say it’s not the best use of your funds.

What about carbohydrates? You should pay attention to carbs if you want to get a bit more dialed-in. Before or after exercise, eating some carbohydrate in addition to your protein (e.g., 4 grams of carbs for every 1 gram of protein) will slightly increase the anabolic effect. This occurs because insulin is involved in the regulation of MPS.

Is it important how much sleep you get? Okay, you’re not asking the question, but I’m pressing it upon you. And the answer is affirmative. Sleep deprivation will increase catabolic pathways, which burn the link between you and muscle growth. So, if you want to look like you have more muscles, get some beauty sleep!

Why Muscle Growth Is Critical

Now that we’ve reached the summit, we can bring it into perspective. Why is it important for everybody, from college freshmen to grandmothers, to gain muscle?

Muscle isn’t just about looks; it’s all about staying fit! Increasing your lean body mass (LBM) will improve your quality of life now and in the future, especially as you get older.

To understand why, you must first understand the importance of protein in the body.

Your body has plenty of places to store fat and carbohydrates, but there’s no real way to “store” protein unless it’s in the form of muscle mass. Your body needs extra protein to survive and recover during medical emergencies, and it gets the protein from muscle tissue. It more make your skin itch to think about losing your hard-won gains, but people with more LBM to use while recovering have better results in the case of serious injuries and critical illness.

Finally, whether you’re young or old, gaining muscle will help you combat two of the most common side effects of aging: muscle loss (sarcopenia) and bone loss (osteoporosis).