Lifting weights three times a week instead of two makes your muscles grow bigger, no matter what type of muscle fibers you have — but it doesn’t make you stronger in one-rep max lifts.
Scientific Claim
Increasing resistance training frequency from 2 to 3 times per week enhances muscle hypertrophy in untrained individuals, regardless of muscle typology, but does not significantly improve maximal dynamic strength gains.
Original Statement
“The limb that trained 3×/week had generally more pronounced hypertrophy than the limb that trained 2×/week, and there was no interaction with muscle typology.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
The within-subject RCT design controls for individual variability and directly compares two frequencies, with statistically significant hypertrophy differences (p=0.0002–0.018) and no interaction effects, supporting definitive causal language.
Evidence from Studies
Supporting (1)
Can muscle typology explain the inter‐individual variability in resistance training adaptations?
This study found that lifting weights 3 times a week instead of 2 builds more muscle for everyone, no matter what kind of muscles they have—but it doesn’t make them significantly stronger. So the claim is right.