The Science of Muscle Growth

Today, we’re taking a break from the practical aspect of fitness and getting down to the nuts and bolts.  Specifically, I’m giving you an informative, yet easy to read, breakdown of the who + what + where + when + why of muscle growth.  While this may seem like not “need to know” information for the casual exerciser, I challenge you to think again.

Developing an understanding of your own body is important.  Also important, understanding the physiologic process behind changes in your body.  And yet even more important, how the choices you make on a daily basis impact those physiologic processes.  Today, we tackle the subject of muscle growth and give you all you need to know to become a better educated exerciser.

Break Down to Build Up

First things first; when you work out, you’re damaging your muscle tissue.  Of course, there’s a difference between tearing a muscle due to terrible form and breaking down muscle fibers through intense exercise. For our purposes today, we’re talking about the latter.

Your body being the self-healing machine that it is, recognizes the damage to these muscle fibers and actively goes to work repairing them.  This repairing process involves the creation of myofibrils (contractile muscle fibers) which fuse to the damaged tissue.  This process thickens the original strand, while also increasing contractile ability (strength).  In other words, you’re getting more muscular and stronger each time you workout and the body repairs itself.

However, these myofibrils don’t just appear out of thin air.  They need to originate from somewhere, and that somewhere is a nucleus. Nuclie are the control center of cells and differentiate which cells do what.  These muscle-building nuclie are added to existing muscle tissue by satellite cells, which function as stem cells. They generate the nucleus which in turn generates increased muscle gain and strength.

Studies have shown that increasing activation of these satellite cells leads to more muscle growth (1). It would follow that performing exercises to especially target these satellite cells would be most efficient. So how do we target these muscle-building cells?  The answer is complex…

How to Impact Muscle Growth

We’ve already recognized our body is pretty smart.  Unfortunately, there is a down side to how smart our bodies can be.  When we lift a load for a significant period of time, our body adapts and fewer muscle fibers are recruited to lift that same weight over a period of time.  This is why changing your workouts + weights is such an important factor in muscle growth.

Increasing muscular tension is imperative if you want to build muscle.  As mentioned, this is done by progressively increasing the weight you’re lifting.  Increasing load will activate a wide array growth factors in the muscle…. as well as  satellite cells (2).

Increasing load will also improve connection of motor units to muscle cells.  In other words, it affects your ability to get stronger without necessarily getting bigger.  Remember this the next time you’re afraid of lifting a heavy weight out of fear of blowing up.  Heavy weights don’t always have to equal giant muscles – diet plays a big part in that.

Hormones and Muscle Growth

Along with the above process, hormones play a crucial part in muscle growth.  In particular, Insulin Growth Factor and testosterone are the two most important when it comes to muscle growth.  Testosterone is a commonly talked about hormone, and studies have shown intense weight lifting will have several affects on testosterone in your body.  Namely…

  1. Most testosterone in your body isn’t free; i.e. it can’t be used for muscle-building purposes.  Strength training frees up more of this bound testosterone making it available to help you add muscle mass.
  2. Muscle cell receptors become more sensitive to testosterone, thereby improving the effects of the hormone.
  3. Insulin Growth Factor improves muscle growth by increasing protein synthesis in the muscle, as well as activates satellite cells to create muscle cell nuclie.

Rest + Grow

The above described muscle-building process takes place over a 24-48 hour window following adequate exercise. During this protein-building phase, your diet becomes especially important.  Feeding the biochemical pathways and giving your body energy to build new tissue is now vital.  Consume the appropriate foods to keep driving muscle growth.

These foods are lean proteins, complex carbohydrates, and essential minerals and vitamins found in a variety of vegetables and, to a lesser degree, fruits.  Bottom line, eat healthy.  You know what healthy is…I know you do.  Eat vegetables, eat lean protein (enough of it), and a moderate amount of complex carbs if you want to add muscle.  Simple as that.

At the end of the day, the most important factors in muscle growth are pushing your muscles with progressively heavier loads, allowing adequate rest, and fueling your muscles through proper nutrition. Of course, each individual is governed by their own genetics.  Some of us have more free testosterone floating around, while others simply have more satellite cells lying around waiting to be activated.  This is why one person may have a harder time building muscle than another.

All you can do is work with what you’ve got and put in your best effort possible. With the above knowledge in hand, you’re now better prepared to attack your own muscle-building goals.  Compare yourself to your prior self, and no one else.  Do your best, lift smart, and good things will surely happen for you.

Have any questions or concerns with the information in this post?  Leave a comment below and we’ll get back to you.






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