The Study
Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations
This study is like a teacher summarizing what lots of other science experiments found about lifting weights — it doesn’t do any new experiments itself. So it can say 'some people saw bigger muscles with one kind of lift, others saw the same with another,' but it can’t say one kind definitely makes muscles bigger.
Analysis score
Maximum 5 for a narrative review.
Where the score came from
Whether you lift a weight up (concentric) or lower it slowly (eccentric), your muscles get about the same size—but they change shape differently inside. Lowering weights makes muscle fibers longer; lifting makes them more angled. Your body uses different tiny signals to build muscle depending on how you move the weight.
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 you don’t need to do only one type of movement to grow muscle; mixing both may optimize structural adaptation.
- 2Muscle size increase: similar for both types.
- 3Fascicle length: greater with lowering.
- 4Pennation angle: greater with lifting.
- 5Protein synthesis: same for both.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Frontiers in Physiology
Year
2017
Authors
M. Franchi, N. Reeves, M. Narici
Related Content
Claims (7)
Your muscles don’t make more protein faster when you lower weights slowly vs. lifting them up—so growth must come from rearranging what’s already there, not just making more.
Lowering weights slowly makes the connective tissue around your muscles rebuild and strengthen more than lifting does, helping your muscle adapt structurally.
Lowering weights slowly makes muscle fibers longer, while lifting them quickly makes them thicker and more angled—both make muscles bigger, but in different ways.
Lowering weights slowly turns on different cellular signals and makes your muscle’s scaffolding change more than lifting does—even if both make your muscle bigger.
Whether you push weights up or lower them slowly, if you do the same amount of total work, your muscles grow about the same size.
Lowering weights slowly wakes up muscle stem cells right after exercise, but lifting weights regularly over time builds up more of these cells permanently.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.