What Is Muscle Hypertrophy?

What Is Muscle Hypertrophy?

Written by Megan Earles

Muscle hypertrophy is a term that is commonly used is weightlifting. It is good to understand what this is as you work to build foundational knowledge in weightlifting. 

Simply put, it is the term used for the growth and increase in size of your muscle cells.

Gains, right? Right!

Hypertrophy is the increase in SIZE of the cells not the Number of cells. This is an important distinction from Hyperplasia which is an increase in the numbers of cells.

The Process

When you start working out, there is an increase in the nerve impulses that cause muscle contractions. One time alone will not gain you a noticeable change in muscle size. It is repeated exercise over months that will increase your protein synthesis and cause your muscles to grow.

What is protein synthesis? Great question!

I think to understand protein synthesis, it is good to go over a few key terms.

Regarding muscles, research coins the term Muscle Protein Synthesis (MPS) and this is the driving force behind adaptive response to exercise (Atherton & Smith, 2012).

On the flip side of that, the Muscle Protein Breakdown (MPB) is a degradation of muscle proteins and a key component of muscle remodeling (Tipton, Hamilton & Gallagher, 2018).

The relationship between MPS and MPB is delicate, hypertrophy occurs when net protein synthesis occurs and that is when MPS exceeds MPB

Net muscle protein balance = Muscle-protein synthesis – Muscle protein breakdown

**NOTE: This is only brushing the surface of these terms, please do more research if you wish to have a deeper understanding of muscle protein***

As you work out, you break down your muscle fibers. This is when these fibers are ready to be repaired and muscle growth will occur.

You may wonder why your body doesn’t react the way someone else’s does and that’s ok. It’s important to keep in mind that your genetics play a huge role in how your muscles react to stimuli such as exercise.

Another common link is between muscle hypertrophy and Delayed Onset Muscle Soreness (DOMS). If you are new to working out, your DOMS may be very pronounced. Beginners also tend to have rapid growth in strength and or muscles – muscle hypertrophy. It is easy to see why they can be interlinked. 

Muscle hypertrophy can occur without DOMS. DOMS is an occurrence that happens during training, not the goal of your training.

Happy lifting my friends! Strive to be better!




Atherton PJ, Smith K. Muscle protein synthesis in response to nutrition and exercise. J Physiol. 2012;590(5):1049–1057. doi:10.1113/jphysiol.2011.225003

Tipton, K. D., Hamilton, D. L., & Gallagher, I. J. (2018). Assessing the Role of Muscle Protein Breakdown in Response to Nutrition and Exercise in Humans. Sports medicine (Auckland, N.Z.)48(Suppl 1), 53–64. doi:10.1007/s40279-017-0845-5

Dankel, S. J., Mattocks, K. T., Jessee, M. B., Buckner, S. L., Mouser, J. G., Counts, B. R., . . . Loenneke, J. P. (2017). Frequency: The overlooked resistance training variable for inducing muscle hypertrophy? Sports Medicine, 47(5), 799-805. doi:http://dx.doi.org.ezproxy.libproxy.db.erau.edu/10.1007/s40279-016-0640-8

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