What Is Hypertrophy?

You might have heard the phrase ‘muscle hypertrophy’ thrown around by avid gym-goers, healthcare professionals, and athletes alike, but what actually is hypertrophy?

What Is Hypertrophy?

Is it a good thing? And what are its causes? Find out everything you need to know and more, by reading this article.

What Exactly Is Hypertrophy 

Hypertrophy is a term used to define the biological process of the increase/growth of muscle cells. This leads to an increase in muscle size and is achieved through exercise. 

For a lot of people, the goal of their workout is hypertrophy - and look either more muscular, more toned, or defined.

Listing weights is generally considered the easiest way to kick start muscular hypertrophy and maintain cell growth. 

The Two Types Of Hypertrophy

There are two types of hypertrophy that you need to know about:

  • Myofibrillar Hypertrophy - is when the number of myofibrils in your muscles increases, which causes muscles to grow in both strength and density. Myofibrils are the proteins in your muscles that help to contract muscles, and cause movement. 
  • Sarcoplasmic Hypertrophy -  muscles contain sarcoplasmic fluid, surrounding the myofibrils. This fluid contains adenosine triphosphate, glycogen, creatine, phosphate, and water, and during exercise, this fluid moves to and is used by your muscles. It is converted into energy. Sarcoplasmic hypertrophy is an increase in this type of fluid, which can make muscles appear larger, but does not increase your overall strength. It is the main biological agent that causes the muscle volume increase called a ‘pump’, immediately after finishing exercise.

Which type of hypertrophy to go for depends on your long-term fitness goals. Training that targets myofibrillar hypertrophy will help to increase your overall strength and your speed.

Alternately, sarcoplasmic growth will help to give your body sustained energy, and therefore is great training for endurance athletic events, such as marathons.

Look at our quick cheat table below to differentiate the two types of muscular hypertrophy. 

Type Of Muscular Hypertrophy Increases Activates
Myofibrillar hypertrophy Strength and speedContractor muscles 
Sarcoplasmic hypertrophy Endurance, and energy storage. Glycogen (energy) storage in muscles. 
The Two Types Of Hypertrophy

What Causes Muscular Hypertrophy? 

Strength training can help you to build muscle, through both types of hypertrophy. The way that you exercise (and lift in particular) will determine the type of hypertrophy, and the way that your muscles grow and change.

Strength training involves exercising against resistance that gradually increases over time. The strain that this increasing resistance puts on your muscles causes damage to muscle fibers, which the body then repairs. 

When muscles are repeatedly challenged by this type of exercise, they will adapt, and grow in both size and strength.

When you are doing weightlifting training, you can perform many repetitions (which are known as reps) at a lower intensity/weight, or you can lift at a heavier weight/intensity for fewer reps. 

Working out with a lighter weight will develop your muscle tone, but it will require a high number of repetitions to improve the efficiency of your muscle fibers.

Unless you carry on performing reps until your muscles have reached the point of fatigue, you will not see much of an increase in muscle definition. 

Alternatively, using heavier weights to work out with will effectively stimulate the growth and definition of muscle fibers. It is a more time-efficient way to work out too, making it a good fit if you are short on time. 

What Stops Muscular Hypertrophy? 

There are a few conditions that stop the muscles from growing through hypertrophy. For example, myofibrillar myopathy (which is a type of muscular dystrophy) results in muscle weakness during mid-adulthood.

Generally, symptoms start at the ends of limbs, in hands and feet, before moving towards the center of the body. 

Doing your workouts incorrectly will also prevent hypertrophy and muscular growth. In order to sustain muscle growth, you have to progressively increase the resistance (i.e. the weights you’re lifting).

If you stay at the same weight for too long, then you will not challenge the muscles enough, which will prevent any hypertrophic muscle growth. 

How To Build Muscle?

How To Build Muscle?

If you want to build muscle through weight lifting, you will need to have both mechanical damage and metabolic fatigue caused by your workouts.

When you lift a heavy weight, the contractile myofibril proteins in the muscles will generate a force to overturn the resistance provided by the weight. 

This will then result in structural damage, which stimulates a repair response within the muscles. These damaged muscle proteins will then result in an increase in their muscle size, which is myofibrillar hypertrophy. 

Mechanical fatigue occurs when your muscles have exhausted the available supply of adenosine triphosphate (ATP), which is an essential energy source that helps your muscles contract.

Once they have used up their available supply, the muscles aren’t able to continue muscular contractions, or can no longer lift the weight properly. This can also lead to muscle gain and growth, but through the sarcoplasmic hypertrophy pathway. 

Mechanical damage and metabolic fatigue are both important for achieving and maintaining muscular hypertrophy. 

However, contrary to common misconceptions, you don’t necessarily need to work your muscles to failure (which is where you are totally unable to follow through with a rep as your muscles are so exhausted). 

A study dated from 2010 found that for maximum muscle gain, there needs to be a significant amount of metabolic stress on the muscle, alongside a moderate degree of muscle tension.

Exercise that involves shortening (concentric) movements at fast-to-moderate speeds for only one to three seconds, and elongating (eccentric) at slower speeds, around two to four seconds, were shown to be highly effective through research. 

An exercise that fulfills these criteria is a weighted bicep curl (which is a concentric movement) done at fast to moderate speeds, followed by a slightly slower return to the starting position, which is an eccentric movement. 

Final Thoughts: A Short Summary Of Muscular Hypertrophy

Muscular hypertrophy is an increase in the volume of a muscle. It happens through two different but linked biological mechanisms - an increase of myofibril proteins, and an increase of sarcoplasmic fluid. 

If you want to grow your muscles, you should strive towards hypertrophy through lifting. You could try one of these lifting schedules: 

  • Lifting three days per week -  which allows your muscles to recover and grow between sessions. 
  • Lifting one or two days per week - which is like above, but better suited to those who are weightlifting novices. 
  • Alternating between working out between upper-body and lower body lifting on different days. This allows different muscle groups to be used each day, giving them rest and recovery time.
Kevin Harris