The Study
The interplay between muscle length, range of motion, and exercise selection: a review
This study is like a teacher summarizing what other scientists have found in their experiments. It says, 'Hey, people who train with their muscles stretched out sometimes get bigger muscles—but we don’t know for sure if stretching is the reason.' So it’s a hint, not a proof.
Analysis score
Maximum 5 for a narrative review.
Where the score came from
When you lift weights and stretch your muscles while they’re under tension, they grow more than when you lift with them barely stretched—even if the weight feels heavier in the short position.
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 51 / 100
Quality score
Based on clinical experience or non-systematic literature reviews. The lowest level of evidence as they are most susceptible to bias and personal perspective.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes—this means choosing exercises like deep squats or full-range deadlifts (where muscles are stretched under load) may build more muscle than partial lifts like knee extensions at the top.
- 2Training with muscles stretched (long length) and under load led to more muscle growth than training with muscles shortened—even when the weight was heavier in the shortened position.
- 3No growth benefit if the stretch had no resistance.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Sports Medicine International Open
Year
2025
Authors
G. F. Pedrosa, Mariano Rezende Pereira, Witalo Kassiano
Related Content
Claims (5)
When people lift weights through a full motion vs. just part of the motion, the muscles might look like they grow more in one case—but that could just be because the weight feels heavier at different points, not because the muscle is stretched more. So we can’t be sure if stretching the muscle is what’s causing the growth.
Lifting weights when your muscles are stretched out more (like at the bottom of a squat or a full bicep curl) tends to make them grow bigger than lifting with your muscles mostly shortened, as long as there's still resistance pushing back when they're stretched.
Just stretching your muscle under light weight won’t make it grow — you need to push hard while it’s stretched out, like doing a bicep curl slowly at the bottom where it’s fully extended.
Doing a full squat or starting a bicep curl from the bottom makes your muscles grow more at the far ends (like the top of your thigh or the outer part of your bicep) than doing partial reps from the top.
Even if you lift heavier weights with your muscles mostly bent, you don’t grow bigger muscles than if you lift lighter weights with your muscles stretched out — the stretch matters more than how heavy the weight is.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.