The Study
Does longer-muscle length resistance training cause greater longitudinal growth in humans? A systematic review
This study looked at lots of other studies and found that lifting weights with your muscles stretched out might make them grow a little more than lifting with them bunched up — but it’s not sure, and the measurements used are kind of shaky. So we can’t say it definitely causes bigger muscles, just that it might be linked.
Analysis score
Maximum 100 for a systematic review.
Where the score came from
Some studies suggest lifting with your muscles stretched out (like deep squats) might make them grow a bit bigger than lifting with them bent, but we’re not sure why or how much.
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 528 / 100
Quality score
Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The differences are small and not clearly meaningful for real-world strength or appearance gains.
- 2Muscle thickness increased a little more with stretched-position training in some muscles (like the thigh), but not all.
- 3Fascicle length changes were inconsistent and possibly fake due to measurement errors.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Sports Medicine and Health Science
Year
2025
Authors
Milo Wolf, P. Korakakis, Michael D. Roberts, Daniel L. Plotkin, M. Franchi, Bret M. Contreras, Menno Henselmans, Stian Larsen, B. Schoenfeld
Related Content
Claims (5)
Resistance training with muscles stretched further may lead to different muscle growth outcomes in people who are new to training versus those who are experienced, but there is not enough reliable data yet to know for sure.
Working your muscles through a fuller range of motion during weight training might make them grow a little bigger than training with a shorter range, but it’s not always clear or the same for every muscle.
Some studies say full-range lifting makes muscle fibers longer, but the tools used to measure this might be inaccurate, so we can’t be sure it’s really happening.
No one has actually counted the tiny units inside muscle fibers to see if full-range lifting adds more of them—so we don’t know if that’s really what’s happening.
Most of the studies on this topic are not very well done—they often don’t report enough details, have small sample sizes, or use shaky methods, so we can’t trust their results fully.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.