The Study
A Systematic Review with Meta-Analysis of the Effect of Resistance Training on Whole-Body Muscle Growth in Healthy Adult Males
This study looked at lots of other studies and found that guys who lifted weights usually gained a little muscle — about the weight of a big bag of sugar. But we don’t know if those original studies were fair tests, so we can’t say lifting weights definitely caused the muscle gain — just that they usually went together.
Analysis score
Maximum 100 for a systematic review with meta-analysis.
Where the score came from
Lifting weights makes muscles bigger, but doing too many sets might actually slow down growth.
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 558 / 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 — gaining 1.5 kg of muscle is noticeable and meaningful for fitness goals, but doing too many sets could hurt progress.
- 2Muscles grew by 1.53 kg on average.
- 3Age and experience didn't change results much.
- 4Every extra set per workout made gains 0.03 kg smaller.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
International Journal of Environmental Research and Public Health
Year
2020
Authors
P. Benito, R. Cupeiro, D. Ramos-Campo, P. Alcaraz, J. Rubio-Arias
Related Content
Claims (6)
When you lift weights over time, the main reason your body becomes leaner and more muscular is because your muscles grow bigger—not because you're losing fat or anything else.
Doing more sets in your weight workouts might actually make you gain less muscle—each extra set could slightly reduce your muscle growth, so more isn’t always better.
If healthy guys between 18 and 40 lift weights regularly for at least two weeks up to a year, they typically gain about 1.5 kilograms of muscle—no matter what kind of weight routine they follow.
If you're a healthy man between 18 and 40 years old, doing strength training will help you build muscle at about the same rate no matter your exact age in that range.
If you're a guy between 18 and 40 and you start lifting weights, whether you're new to it or have been doing it for years, you probably won't gain much more muscle just because you're experienced—but the people who’ve trained the longest (4+ years) still tend to gain the most muscle, so experience doesn’t always make a clear difference.
No matter which way you measure muscle growth—whether you count all non-fat weight, lean tissue, or just skeletal muscle—you get pretty much the same result when guys lift weights. So, you can use any of these methods and still track muscle gain accurately.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.