Two Types of Muscle Growth

Two Types of Muscle Growth

Becoming bigger, stronger, and better-looking are the major reasons many of us began weight training.And while lifting may seem pretty straightforward, how your muscles grow (and look) depends on which hypertrophy you are training for.

Generally speaking, there are two of them:

  • Myofibrillar hypertrophy
  • Sarcoplasmic hypertrophy

Myofibrillar hypertrophy is the increase in the size of the muscle contractile units, called ‘myofibrils’ and commonly known as “muscle fibers”. These muscle fibers are the contractile elements of the trained muscle groups, which allow contraction and relaxation. Sarcoplasmic hypertrophy, on the other hand, is the growth of the ‘sarcoplasm’, which is basically a jelly-like fluid that surrounds the muscle fibers.

The sarcoplasm contains different non-contractile elements, which can grow in volume, depending on the type of training.It appears that the myofibrils are more closely related to the maximum output of strength and explosiveness, while their sarcoplasm is engaged during intense, yet longer loads.

In other words, myofibrillar hypertrophy is a result of a powerlifting approach to weight training, where you do 1-5 repetitions. Oppositely, sarcoplasmic hypertrophy is a result of a bodybuilding approach to training, where you do 6-15+ repetitions with heavy weights.

Which one should you train for?

Take a look at the picture below. 

The bodybuilder on the left trains primarily for sarcoplasmic hypertrophy. His muscle looks more “pumped” up because they’re filled with sarcoplasm. While the sprinter on the left trains solely for myofibrillar hypertrophy. His muscles are not as big, but he does look leaner and more cut because his actual muscle fibers are denser.

Ultimately, there’s no right or wrong answer. You should train for whatever aligns with your fitness goals. But don’t completely neglect one type of training for another. Try to stimulate both types of muscle growth, as well as other functions like balance, agility, and coordination. Become a functional human being.

Stay fit my friend,


Founder & CEO

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