The Study
Comparing the effects of low and high load resistance exercise to failure on adaptive responses to resistance exercise in young women
This study is like comparing two recipes for building muscle - one using heavy weights and one using light weights. It shows both recipes seemed to work about the same for the women in this small test group, but we can't be sure the weights themselves caused the results because the test wasn't perfect.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Young women lifted weights until they couldn't lift anymore, using either light or heavy weights. Both groups got stronger and their muscles grew the same amount.
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 540 / 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 for general health and fitness.
- 2Muscle size grew 6-9% and strength increased 15-27% after 6 weeks, with no difference between light and heavy weights.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Sports Sciences
Year
2019
Authors
D. G. A. Stefanaki, A. Dzulkarnain, Stuart R. Gray
Related Content
Claims (10)
For people who already lift weights, pushing to muscle failure with either light or heavy weights gives the same muscle growth and strength improvements after 12 weeks.
When you lift weights until you can't anymore, you build similar muscle size no matter how heavy the weights are, but lifting heavier weights makes you stronger and faster at moving them than lighter weights.
When lifting lighter weights, pushing until you can't lift anymore helps build bigger muscles, but this doesn't happen with heavier weights. Heavier weights always build more strength than lighter ones, no matter how hard you push.
When young women lift weights until they can't anymore, their arm and leg muscles get thicker by about 6-9% after 6 weeks. It doesn't matter if they lift heavy or light weights—both work the same for muscle growth.
When young women do strength exercises until they can't do any more, their arm and leg muscles get stronger by about 15-27% after 6 weeks. It doesn't matter if they lift heavy or light weights—both ways work just as well for building strength.
This study shows that when young women lift weights until they can't anymore, it doesn't matter if they use light or heavy weights—both ways build muscle about the same.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.