Non-functional (sarcoplasmic) hypertrophy: myth or fact?

Muscle growth, or skeletal muscle hypertrophy, is a complex process involving the thickening of contractile proteins and the body's response to maintain internal spacing. Recent studies have highlighted the existence of sarcoplasmic hypertrophy, where the muscle enlarges without a corresponding increase in strength, drawing parallels to the adaptive nature of the nervous system's neuroplasticity.

When we dive into the world of fitness and muscle development, there's a multitude of information, both anecdotal and scientific, that's presented to us. But how much of it is truly rooted in science? Let's explore the complex mechanism of muscle growth, particularly the concept of skeletal muscle hypertrophy.

What is muscle hypertrophy? 

At its core, skeletal muscle hypertrophy is the increase in contractile proteins, namely myosin and actin. As these proteins thicken, they influence and potentially disrupt the lattice spacing within the muscle. This internal "crowding" prompts the body to increase the diameter of the entire muscle cell. It's akin to two people in a room growing in size; to avoid crowding, the room must expand.

Non-functional hypertrophy: no strength, just bulk? 

For years, there has been a debate about the existence of non-functional hypertrophy, often termed as sarcoplasmic hypertrophy. Contrary to the belief that it's mere "bro science," recent studies have shown that sarcoplasmic hypertrophy might indeed be a reality. It refers to an increase in fluid within the muscle fiber. This leads to a larger muscle diameter without an addition of contractile units, meaning there's no corresponding increase in force production. In layman's terms, the muscle becomes larger, but not necessarily stronger. This is not due to bloating or any adverse effect but simply a retention of more hydration within the cell. Over time, as one progresses in their training journey, the source of hypertrophy might shift from contractile units to sarcoplasmic, explaining why some individuals experience an increase in muscle size without a proportional increase in strength.

Drawing a parallel from the nervous system, this multifaceted growth mechanism is reminiscent of neuroplasticity. The nervous system adapts and evolves in response to various stimuli, experiences, and even injuries. Similarly, there are multiple pathways leading to strength increase and muscle hypertrophy. The paths to these goals might overlap or be distinct, depending on several factors, including exercise types, repetition schemes, rest intervals, and more.


In conclusion, the journey of muscle development and strength increase is intricate and multi-dimensional. As science continues to unravel its complexities, one thing is clear: there's no one-size-fits-all approach. Embracing a holistic and informed perspective, rooted in research, is key to achieving one's fitness goals.

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