The Study
How Slow Should You Go? A Systematic Review With Meta-Analysis of the Effect of Resistance Training Repetition Tempo on Muscle Hypertrophy
This study looked at lots of other studies about how fast or slow you lift weights and whether that makes your muscles bigger. It says there’s probably not much difference, but we don’t know if those original studies were done really well — so we can’t say lifting slowly definitely makes you stronger, just that it might not matter much.
Analysis score
Maximum 100 for a systematic review with meta-analysis.
Where the score came from
Scientists looked at many studies to see if lifting weights slowly or quickly makes your muscles grow more.
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.
- 1No, the difference is so tiny it won't make a noticeable difference in how big your muscles get.
- 2Slow lifts: +0.34 muscle gain units.
- 3Fast lifts: +0.43 muscle gain units.
- 4Difference: only 0.09 — too small to matter.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Strength & Conditioning Research
Year
2025
Authors
Alysson Enes, A. Piñero, Thomas Hermann, Arman Zamanzadeh, T. Hennessy, Daniel Montenegro, Chris Parnell, Albert Jia, Tami Weitzman, Milo Wolf, P. Korakakis, P. Swinton, Brad J. Schoenfeld
Related Content
Claims (10)
To figure out whether speeding up or slowing down the lifting vs. lowering part of a weight workout makes your muscles grow more, scientists need to test each part separately—not at the same time.
How fast or slow you lift and lower weights doesn’t matter as much for building muscle as how much weight you lift, how many reps you do, or how close you push yourself to failure.
If you lift and lower weights quickly or slowly, as long as you do both phases the same way, your muscles grow about the same amount—speed doesn’t make a big difference.
Lifting weights fast or slow doesn’t make much difference in how much your muscles grow — the extra gain from going slow is practically nothing.
How fast or slow you lift and lower weights probably doesn’t make much difference in how much muscle you build—unless there’s some special situation we haven’t figured out yet.
If you lift weights until you're really tired, it doesn't matter if you lift slowly or quickly—you'll still build about the same amount of muscle.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.