The Study
Comparable Strength and Hypertrophic Adaptations to Low-Load and High-Load Resistance Exercise Training in Trained Individuals: Many Roads Lead to Rome
This study is like comparing two different recipes for making muscles stronger. It shows that both recipes seem to work, but it can't prove that one recipe actually causes better results than the other because they didn't mix up the ingredients randomly.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists tested if lifting light weights many times works as well as heavy weights few times.
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 537 / 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, shows both light and heavy weight training can build muscle and strength when pushed to failure.
- 2Light weights built same leg muscle size (7-9% bigger) and multi-joint strength (21% stronger) as heavy weights.
- 3Heavy weights better for single-joint strength.
- 4Light weights better for endurance (9% better vs 3% worse).
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
bioRxiv
Year
2025
Authors
Kristoffer Toldnes Cumming, Ingrid Cecelia Elvatun, Richard Kalenius, Gordan Divljak, T. Raastad, N. Psilander, Oscar Horwath
Related Content
Claims (6)
When people who are already fit push themselves as hard as they can during weight training, it doesn't matter if they lift heavy weights for a few reps or lighter weights for many reps—both ways build muscle about the same.
Lifting lighter weights many times until you can't do any more builds as much muscle as lifting heavy weights a few times in people who already exercise regularly.
Lifting lighter weights many times until you can't do more builds muscle strength just as well as lifting heavy weights a few times until you can't do more, for people who already work out.
Lifting lighter weights many times until you can't do more improves muscle endurance better than lifting heavy weights just a few times, especially for people who already work out.
Whether you lift heavy weights for a few reps or lighter weights for more reps until you can't do any more, both ways make your thigh muscles grow about the same amount in people who already work out.
Lifting heavy weights for just a few reps makes you stronger in exercises that work one muscle at a time, more than lifting lighter weights for many reps, especially if you already work out regularly.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.