The Study
Do the anatomical and physiological properties of a muscle determine its adaptive response to different loading protocols?
This study is like a science experiment where people did different exercises to see what makes muscles grow. It shows that for calf muscles in young men, using light weights or heavy weights both made muscles bigger and stronger in a similar way. But we don't know if this works for other muscles or different people like women or older adults.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Using light or heavy weights made calf muscles bigger and stronger equally in young men who trained hard.
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 541 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes, these are meaningful improvements in muscle size and strength.
- 2Muscles grew 9-11% bigger and got 15-18% stronger after 8 weeks.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Physiological Reports
Year
2020
Authors
B. Schoenfeld, A. Vigotsky, J. Grgic, Cody T Haun, B. Contreras, Kenneth Delcastillo, Aston Francis, Gilda Cote, Andrew Alto
Related Content
Videos (3)
Claims (5)
When untrained young men lift lighter weights many times until they can't lift anymore, it builds just as much muscle in their calf muscles as lifting heavier weights fewer times. Both ways made their muscles about 10% bigger after 8 weeks.
When people do strength training, the outer calf muscle grows more than the inner calf muscles, no matter how they lift weights. This shows that some muscles naturally grow faster than others.
For beginners, lifting heavy weights a few times or lighter weights many times both make your calf muscles about 15-18% stronger after 8 weeks.
Different types of muscle fibers in your calf muscles don't affect how much they grow from lifting heavy or light weights, because both the mostly slow-twitch and mixed fiber muscles grew about the same with both types of training.
When untrained young men lift weights until they can't lift anymore, their calf muscles grow bigger by 7-14%, no matter how heavy the weights are. This shows that pushing hard is what makes muscles grow, not how heavy the weight is.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.