The Study
Muscular adaptations in low- versus high-load resistance training: A meta-analysis
This study looked at lots of other studies and found that lifting heavy weights might help you get stronger and bigger muscles a little more than lifting light weights, but it’s not super sure — the results are close, like flipping a coin and getting heads 55% of the time. We can’t say for sure that heavy weights cause better results because we don’t know how the original studies were done.
Analysis score
Maximum 100 for a systematic review with meta-analysis.
Where the score came from
This study looked at whether lifting light weights (like 5-10 reps) is as good as lifting heavy weights (like 3-5 reps) for building muscle and strength.
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 539 / 100
Quality score
The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — even light weights can build muscle and strength, but heavier weights may help a bit more, though the difference is small and not certain.
- 2Light weights (≤50% 1 RM) improved strength (ES=1.23) and muscle growth (ES=0.39).
- 3Heavy weights improved strength more (ES=2.30) and muscle growth more (ES=0.82), but the differences weren't big enough to be sure they weren't due to chance.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
European Journal of Sport Science
Year
2016
Authors
B. Schoenfeld, Jacob M. Wilson, Ryan P. Lowery, J. Krieger
Related Content
Claims (8)
If you lift light weights for more reps or heavy weights for fewer reps—but do the same total amount of work—you’ll grow your muscles just as much either way.
Current scientific evidence does not show that some people consistently gain more muscle from lifting heavy weights with few repetitions versus lifting lighter weights with many repetitions.
High-load resistance training shows a small, non-significant trend toward greater muscle strength gains than low-load training, based on combined data from nine studies.
Lifting light weights—less than half of what you can lift once—can still help beginners get stronger and build muscle, but not as much as lifting heavier weights.
Lifting heavier weights might help you get stronger a bit more than lifting lighter weights, but the difference is so small that we can’t be sure it’s real — it could just be luck.
Lifting heavy weights might help you build slightly more muscle than lifting light weights if you're new to training, but the difference isn't big enough to say for sure it's real.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.