The Study
Can muscle typology explain the inter‐individual variability in resistance training adaptations?
This study is like a fair race where everyone got randomly assigned to either train 2 times or 3 times a week, and then we checked who got stronger. It tells us that training more often made muscles bigger — but it didn’t show that people with more fast-twitch muscles got stronger than others.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study looked at why some people get much bigger and stronger from lifting weights than others, even when they do the same workout.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 562 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — training more often helps muscles grow, and people with different muscle types need to work harder to get the same results, so one-size-fits-all workouts may not be optimal.
- 2People who trained 3 times a week got bigger muscles than those who trained 2 times.
- 3People with slower muscle fibers had to lift more total weight to get the same results as those with faster fibers.
- 4Muscle fibers didn't get thicker on average, but muscles still got bigger.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of Physiology
Year
2023
Authors
Kim Van Vossel, Julie Hardeel, Freek Van de Casteele, Thibaux Van der Stede, Anneleen Weyns, Jan Boone, Silvia Salinas Blemker, Eline Lievens, Wim Derave
Related Content
Claims (10)
People might respond differently to how much weight training they do, but we can't say for sure because the studies done so far aren't clear enough.
Everyone’s body responds differently to workouts—what works wonders for one person might be too much or too little for another, because of differences in genes, energy use, and how fast they recover.
Whether someone has more slow-twitch or fast-twitch muscle fibers doesn't predict how much bigger or stronger their muscles will get after 10 weeks of lifting weights to exhaustion, even though people's results vary a lot.
People with more slow-twitch muscles have to do more reps and lift more total weight to get the same muscle growth as people with more fast-twitch muscles, even when both train until exhaustion.
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.
Even though muscles get bigger after 10 weeks of weightlifting, the individual muscle fibers don’t necessarily get thicker — the growth might come from how the fibers are arranged, not from each one swelling up.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.