How Do Muscles Grow? 💪

Did you know there are more than 600 muscles in the human body?  We can either be impressed by that level of coordination to help us move or totally unsurprised when it feels like every last one of them is sore after a particularly challenging workout.  

We’re all told to eat protein to grow our muscles, but like everything in the human body, it really isn’t that simple.  As they are seemingly a large part of our body and function, it pays to look at them in a little more detail and see how do muscles grow. 

What is Muscle?

A kind of elastic tissue makes up each muscle and each muscle is actually made up of tens of thousands of small muscle fibers.  Nerve cells control the contraction of muscles and the muscle’s strength largely depends on how many fibers are present. This is an important note to make; whilst there is disagreement on recovery within the sports world, we know that we need to recover from a neuromuscular point of view too – and this can take up to 72 hours (so give yourself plenty of time if you need it!). 

For a muscle to “work,” our body uses the food we eat and converts it into adenosine triphosphate (ATP) our energy currency.  Muscle cells use this ATP to contract.  When you feel like you have nothing left in the tank – the body is running out of compounds to produce this energy.   

We humans have three types of muscle:

💀 Skeletal, 

😏 Smooth, 

🫀 Cardiac

Skeletal muscles

These move the external parts of the body and the limbs, and they work in pairs. When one muscle in the pair contracts, the other expands, and this lets us move.  

Muscles attach to strong tendons, which either attach to or directly connect with the bones. Muscles and tendons together keep bones in the right position, so the joints do not dislocate.

Skeletal muscles also generate heat when they contract and release, and this helps maintain body temperature.

There are two main skeletal muscles:

  • Type I
  • Type II


👉 Type I

Also known as slow-twitch muscle fibers.  They are rich in mitochondria.  If you flashback to biology 101, you’ll remember that the mitochondria are the powerhouse of the cell.  Type I fibers sustain aerobic activity; meaning they use oxygen to help generate energy.  They can use both carbohydrates and fat as energy.  What this tells us is that if we want to move well during our workouts, we need to eat enough to fuel them!  And that includes carbs and good fats!

👉 Type II

Also known as fast-twitch muscle fibers.  These are less dense in mitochondria.  These muscle fibers can sustain anaerobic activity, meaning they can generate energy in the absence of oxygen.  This is what the 100m sprinter would utilise – because they need rapid contraction with a lot of force.  These muscle fibers will rely on glycogen that the body already has stored in its muscles or in the liver.  

Smooth Muscles

Are responsible for movements in the stomach, intestines, blood vessels, and hollow organs.  These muscles will work automatically – meaning we don’t tend to have conscious control over what they are doing.  For example, we don’t consciously move food throughout our digestive system, our autonomic nervous system does that for us.    

The arrector pili muscles in the skin are also smooth muscle fibers – these are the ones that make your hair stand on end when you are cold!

Cardiac muscles are those found in the heart and are responsible for our heartbeat.  They contract so the heart squeezes out blood and then relaxes so it can fill up with blood again.  This is also important when we are working out as we need oxygen-filled blood, pumping to our oxygen-dependent muscle fibers!

Growing Our Muscles 

Without heading into clinical issues with our muscles, there are some common muscle challenges we face when we are working out (and recovering). 

Muscle Gain 

This is a common aim for many when they are working out.  The basic premise of muscle gain is that you challenge the muscle, it experiences slight tears and then through recovery it comes back bigger and stronger.  

But if this is to occur, the body needs the right building blocks to rebuild a bigger and better muscle. 

Protein is top of the list.  

When we eat a source of protein, it is digested and then the liver rearranges the component amino acids into new proteins. These are then sent around the body to carry out their specific role; including rebuilding muscle.  

Variety is the spice of life, so ensure you are eating a wide range of protein sources:

👉 Chicken

👉 Fish

👉 Beef 

👉 Dairy 

👉 Beans 

👉 Legumes

👉 Seafood 

👉 Soy 

👉 Eggs 

If we want the right nutrients to get to the muscle to do their job, they need to have an easy transport system.  Water intake is therefore crucial to this.  Opt for filtered water where possible to also remove any additional burden on your detoxification pathways. 

Muscle Cramps

This occurs when the balance in the muscles is a little awry.  As we have mentioned, for muscle movement to occur, contraction and relaxation are involved.  This is achieved by having the right balance of electrolytes in the body.  

Electrolytes are chemicals that conduct electricity when dissolved in water.  They regulate nerve and muscle function, along with balancing blood acidity and pressure, and they help rebuild damaged tissue too!

The electrolytes found in the human body include:

💥 Sodium, 

💥 Potassium, 

💥 Calcium, 

💥 Bicarbonate, 

💥 Magnesium, 

💥 Chloride, 

💥 Phosphate.

A muscle needs calcium, sodium, and potassium to contract.  This also applies to the heart muscle! Important electrolytes are lost in sweat during exercise and in a rapid loss of fluids like in diarrhoea or vomiting.

Food Sources:


Yogurt, fortified milk, and cereals, cheese, tofu, and spinach.


Leafy greens, beans, and other legumes, squash, nuts and seeds and whole grains.


Bananas, squash, sweet potatoes, broccoli, chicken and salmon.


Seaweed, rye, tomatoes, lettuce, celery, and olives.


(Delayed Onset Muscle Soreness) has become a medal of honour for some, but it’s a myth that it’s a sign of a good workout.  

This happens as a result of the micro-trauma in the muscle fibers, which leads to inflammation.  In addition, creates changes in normal levels of electrolytes and other fluids near the affected muscle.  

Inflammation is a normal response in the body created by the immune system.  It’s the immune system’s way of sending all the necessary supplies to help fix the problem.  

Inflammation is a necessary response; the issue is if it becomes unmanaged and chronic.  

Omega-3 fatty acids are a great modulator of the inflammatory response.  

Prostaglandins are compounds that contribute to the inflammatory response, and they are derived from omega-6 fatty acids.  When we over-consume omega-6 fatty acids, this can become an issue.  But if we ramp up our omega-3 consumption, it can help balance things out.  

Omega 6 Fatty Acid Sources

👉 Safflower oil 

👉 Sunflower oil

👉 Corn oil

👉 Soybean oil

👉 Sunflower seeds

👉 Omega-3 Fatty Acid Sources

👉 Oily fish such as salmon, herring, mackerel, and sardines

👉 Fish oil

👉 Flaxseed oil & flaxseeds

👉 Walnuts

👉 Chia seeds

👉 You can also supplement Omega-3 Fatty Acids


In nourishing our muscles, they need fuel to do their jobs, this means eating enough carbohydrates and fats to convert to energy.  When we challenge our muscles, we create microtears that need to recover; for this to occur we need to provide the building blocks to do so.  Protein is key here.  To ensure our muscles get the messages they need from nerve cells, they need sufficient levels of micronutrients, especially those electrolytes.  Finally, during recovery we need to ensure inflammation doesn’t get out of hand; we of course can support this by including omega-3 fatty acids but remember to give your muscles sufficient rest and recovery between workouts too!