In today’s blog post, we will be discussing why some resistance training studies show superior muscle hypertrophy when compared to lower training volumes, such as performing just one set to failure. Although there is no definitive evidence yet, the current data allows us to make reasonable assumptions and propose theories that may explain this phenomenon.
Randomized controlled trials published in resistance training and exercise science journals frequently examine how different training volumes affect muscle strength and hypertrophy. These outcomes are measured independently using methods specific to each property. Strength is typically assessed using a one-repetition maximum (1RM) test, while hypertrophy is usually evaluated through ultrasound measurements of muscle cross-sectional area.
Many of these studies, especially those published in recent years, show greater muscle hypertrophy when higher training volumes are used. Strength improvements generally follow a similar trend, but the increase is usually much less pronounced than the increase in muscle size. A recent meta-analysis demonstrated that hypertrophy tends to increase with rising training volume up to a certain point, while strength plateaus at roughly four sets to failure per week. This raises an important question: what could explain the imbalance between hypertrophy and strength outcomes?
One theory is that higher training volume may stimulate hypertrophy in muscle components that do not significantly contribute to force production, particularly the sarcoplasm. Known as the sarcoplasmic hypertrophy theory, it proposes that muscle growth can occur through an increase in non-contractile elements within the muscle. This concept is still under investigation, and there is no conclusive proof that it occurs to a meaningful extent.
Another theory suggests that high training volumes cause temporary muscle swelling. Whether this swelling results from muscle damage, fluid accumulation, or other mechanisms is not yet fully understood. However, we do know that large training volumes can produce a noticeable increase in muscle size in the short term, even if the effect is not directly tied to long-term structural hypertrophy.
The main takeaway is that if your goal is purely muscle size, higher training volumes may lead to greater increases, whether through true hypertrophy or temporary swelling. However, it is important to remember that this approach also comes with a higher risk of injury and requires disproportionately more time in the gym for the very minor and temporary additional results gained.