What is Muscle hypertrophy?
Muscle hypertrophy is a fancy term for muscle growth. It's what happens when your muscle cells increase in size, usually due to weightlifting or resistance training. If your goal is to tone up or boost muscle definition, lifting weights is one of the most effective ways to achieve it [1].
Interestingly, hypertrophy isn’t just about muscles you work out at the gym—it can happen in your heart, too. When the heart faces added stress, like high blood pressure, its walls can thicken as an adaptive response to handle the extra load. In the short term, this can be helpful. But if the thickening keeps progressing, it can lead to serious issues down the line, increasing the risk of heart-related problems and even mortality [2].
What is Sarcoplasmic hypertrophy?
Sarcoplasmic hypertrophy is about growing the "stuff" inside your muscle cells that isn’t directly responsible for contraction. This includes the sarcoplasm, a fluid that makes up a significant chunk of muscle size. While it doesn't make you stronger per se, it does contribute to the overall bulk of your muscles [1, 3].
If you’re into resistance training, this hypertrophy often means your muscles store more glycogen. That’s great for endurance athletes because it gives you sustained energy during long or repetitive efforts. Think of it like filling your muscles with extra fuel for the long haul. For lifters, cranking out higher reps with lighter weights stimulates muscle growth [1].
But here’s the key difference: unlike myofibrillar hypertrophy, which builds muscle fibres for strength, sarcoplasmic hypertrophy focuses on size and endurance, not raw power [1].
What is Myofibrillar hypertrophy?
Myofibrillar hypertrophy is all about building the machinery that powers your muscles. It involves increasing the size and density of myofibrils, the tiny, contractile structures in muscle cells that make movement possible. This type of muscle growth translates directly into improved strength and speed since it boosts your muscles’ ability to generate force [1].
If you’re hitting the gym to get stronger or more defined, focusing on lifting heavy weights with fewer reps is key. This type of training puts mechanical stress on your muscles, triggering myofibrillar hypertrophy. Your muscles say, “We need to be stronger to handle this!” [1].
The science behind this process, called myofibrillogenesis, involves increasing either the size or the number of these contractile units. This radial growth is a direct response to resistance training, where your muscles adapt to the increased load by adding more force-generating fibres [4, 5].
In short, myofibrillar hypertrophy builds strength from the inside out. It’s less about muscle size and more about function and performance—making it a favourite for athletes and anyone focused on building real, usable strength.
What type of hypertrophy is more desired?
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In conclusion, the type of hypertrophy that is more desired depends on whether the individual's fitness goals are geared more towards strength and speed or endurance.