When men and women who are healthy and in their 20s to 40s do strength training, they both gain about the same amount of muscle relative to how much they started with—men might gain a tiny bit more, but it’s so small it doesn’t really matter.
Claim Language
Language Strength
probability
Uses probability language (may, likely, can)
The claim uses phrases like 'estimated', 'suggesting', and 'not meaningfully different', which indicate uncertainty and likelihood rather than certainty. These terms imply a probabilistic interpretation of the data, not a definitive conclusion.
Context Details
Domain
exercise_science
Population
human
Subject
healthy young to middle-aged adults
Action
exhibiting
Target
relative muscle hypertrophy following resistance training
Intervention Details
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Evidence from Studies
Supporting (1)
Sex differences in absolute and relative changes in muscle size following resistance training in healthy adults: a systematic review with Bayesian meta-analysis
The study found that when men and women do the same strength training, their muscles grow at about the same rate relative to how big they were at the start — so sex doesn’t really affect how much muscle you gain proportionally.