Building bigger muscles might do more than help you lift heavier weights. A new research review published October 13 in Sports Medicine explores whether muscle growth itself could help your muscles resist fatigue, potentially allowing you to perform more repetitions before tiring.
The researchers found that muscle size and muscular endurance often improve together. But there’s a catch: scientists still don’t know whether growing larger muscles actually causes those endurance gains.
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Why Bigger Muscles Might Resist Fatigue
Researchers examined previous resistance-training studies to understand why muscle growth and endurance frequently improve together.
Their central question challenges the assumption that bigger muscles primarily exist to produce greater force. Muscle growth could also help maintain force when repeated contractions become exhausting.
The authors explain that muscle growth may have a functional role in “maintaining/prolonging force generation during disruptive fatigue-related processes.”
Possible explanations include additional contractile proteins, changes in oxygen delivery, and metabolic adaptations. However, these remain proposed mechanisms rather than established explanations.
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Why Lifting Heavier Isn’t the Same as Lasting Longer
The distinction matters because building muscle, increasing maximal strength, and improving endurance aren’t identical goals.
The review notes that both lighter and heavier weights can stimulate muscle growth, particularly when sets approach muscular failure. Yet heavier training generally produces greater improvements in maximal lifting strength.
The authors emphasize that “no causal relationship can currently be established” between muscle growth and improvements in absolute muscular endurance.
They also acknowledge that “neural and metabolic changes inherent to resistance training may be driving increased endurance.”
In other words, someone might build muscle and complete more repetitions without the additional muscle tissue being responsible for the improvement.
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What This Means for Your Next Workout
For lifters, the practical message isn’t to abandon heavy weights or chase endless repetitions.
Instead, understand what you’re training for. Heavy lifting remains valuable for maximal strength, while challenging sets across different loads can build muscle.
If your goal is performing more repetitions at a particular weight, track that performance separately from your strength gains and changes in muscle size.
The researchers conclude that future studies must determine whether muscle growth directly contributes to fatigue resistance.
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