How do Muscles Grow? The Fundamentals & Mechanics of Muscle Building

Written by - Reviewed by Consumer Health Digest Team

Published: May 16, 2018 | Last Updated: Aug 3, 2019

Muscle Building
Weight training is, and has been, a popular way to get in shape. Combined with some cardio vascular training, it accomplishes two things simultaneously:

The problem is, many people, even guys, go about it all wrong. They come home exhausted, and over time, they see no results. Part of the reason for that is they don’t understand how to build muscles the right way.

In this article, we’ll help you understand the mechanics of muscle building, and here we’re talking about the muscles that are connected to your skeleton.

The Neurology of Muscle Growth

There’s a saying that cleverly can have a double meaning when it comes to muscle building:

“It all starts in the mind.”

What we’re referring to is the neurologic process that goes inside of the mind. Motor neurons send signals, or “tell” them, to contract. The more often those same signals are repeated, the stronger they become – and the stronger you become.

Simply put, you’re not just building muscles; you’re building the “electronic connections” to make those contractions stronger and stronger.

The 3-Part Bodily Process of Muscle Growth

Process of Muscle Growth

Did you know that some stress is actually good for your body? It sounds counter-intuitive, but you cannot build muscle without it.

Of course, the stress we’re talking about is when you work out. During and after this stress, a three-part process is going on inside, all to the growth of your muscle cells, and in turn, your muscles.

1. Tension

To illustrate this, let’s go to the gym. During your first week, you did squats at 100 pounds, and your biceps at 10 pounds, for example.

This is actually not a bad idea, by the way. Starting with comfortable weights will help you maintain good form, and help prevent injury from lifting too heavy.

So in the weeks to come, you need to gradually increase the weight for each muscle group to add tension to them. It’s that gradual, increased tension that activates the muscle growth process.

2. Damage

Can you recall that first morning after you began a weight training regimen, getting out of bed groaning from pain, in the same muscle areas you worked the day before?

Keep in mind that while soreness is a physical manifestation that you “damaged” your muscles, it’s not always the case with everyone. But sore or not, this damage activates what are called satellite cells that being repairing the damage.

3. Metabolic Stress

Simply put, metabolic stress is that “rush” or “burn” feeling you get in your muscles when performing an exercise – in this case, lifting weights. This is a result of blood flow going to your muscles. It is also commonly referred to as “the pump.”

Your muscles need things to grow and recover, that only your blood can bring them. These include oxygen and nutrients.

So when you’re working out, your muscles feel a bit larger. Your body triggers the extra blood flow to your muscles, which it needs.

Interestingly, many people who lift weights, especially bodybuilders, describe a euphoric feeling that accompanies this process, making you feel “pumped” during your workout.

Notes About Working Out

Notes About Working Out

Whether you’re lifting weights or anything else, you must realize that your body is going to be adjusting to this new experience. And it’s important to know that you are the biggest factor in helping your body to make that adjustment.

We’re now going to look at two major factors: Diet and rest.


In most cases, you cannot eat the same way you did prior to beginning your weight-lifting routine. Your nutrition has to at least reasonably change for your muscle-building endeavors to be successful.

This doesn’t mean you have to eliminate everything from your diet. But if you’re a “junk-food-a-holic,” for example, seriously cut it back. Junk foods not only lack nutrition; they can also be very high in sodium.

At the same time, increase your intake of healthy foods. You don’t have to stick to “rabbit food” to make this work. Whatever you do, make sure that protein intake is a top priority. It is essential to muscle growth.

Speaking of protein, many who lift weights often include protein powder in their nutritional strategy. If you are unfamiliar with these, it would be wise to speak to a ProteinPowderXpert and understand the role it plays in muscle building.

A word of caution about eliminating some foods entirely: It can be a double-edged sword. If you go without it for too long, reintroducing the food can put your body in shock and make you sick. So unless you are determined to never eat it again, and/or the food will pose some health risk, you may just want to periodically have it to balance the scales.

Some personal trainers have figured out a way to keep this balance while maintaining great physical condition. One day per week, they have what is called a “cheat day”[1]. So for 6 days, they eat healthily, and then on the cheat day, they eat whatever they want.



People often make the mistake of working for every muscle group every day. With total body machines, this might be okay. However, if you’re lifting weights, it can actually do more harm than good.

Muscles that have been worked out need a chance to recover from the “damage” done from a workout. The body kicks in to repair those damaged muscle fibers to prepare it to take on more damage.

Let’s take a basic routine recommended by many personal trainers. On Monday, Wednesday and Friday, they work certain muscles only, like the legs and the core muscles. On Tuesday and Thursday, the arms and other groups only get worked. The groups that are worked on Monday, Wednesday and Friday are not working on these days, and vice versa.

Then you take the weekend off or do a bit of cardio if it’s not during the weekday workouts. This routine gives all the muscle groups time to recover in between workouts.

Don’t Rush It!

While there are certain common denominators to muscle building, it’s certainly not “cookie cutter.” Everyone’s physical makes up is as unique as their fingerprints.

There are a host of factors that can have an impact on your muscle growth. Some gain it quicker than others. But generally, muscle building is slow, even when all things are ideal. So just remember, anything worthwhile takes time. Don’t rush it.


So what have you learned? You learned that muscle building is as much neurological as it is physiological. Muscles breakdown and build through tension, damage and metabolic stress. Make sure a balanced (not necessarily restrictive) diet and rest are an important part of your routine. And finally, you learned that muscle building takes time, so don’t rush it.

We hope this article will be helpful to you in your muscle-building endeavors.

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