The Study
Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis
This study looked at lots of different experiments where people lifted weights with either heavy or light loads and compared what happened to their muscles and strength. It found that heavy weights make you stronger in big lifts, but both heavy and light weights can make your muscles bigger. But it didn't prove one causes the other—it just shows they're connected.
Analysis score
Maximum 85 for a systematic review with meta-analysis.
Where the score came from
If you lift weights until you can't do another rep, both heavy and light weights can make your muscles bigger, but only heavy weights make you much stronger at lifting the heaviest possible 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 539 / 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.
- 1Yes — if your goal is pure strength (like lifting your max), use heavy weights.
- 2If you want bigger muscles, light weights work just as well as long as you push to failure.
- 3Heavy weights: 35.4% stronger in 1RM; Light weights: 28.0% stronger in 1RM.
- 4Muscle growth: 8.3% with heavy, 7.0% with light — no big difference.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Strength and Conditioning Research
Year
2017
Authors
B. Schoenfeld, J. Grgic, Daniel I. Ogborn, J. Krieger
Related Content
Claims (7)
When people lift weights until they can no longer complete another repetition, the amount of muscle growth is similar whether they use light, moderate, or heavy weights.
When resistance training is performed until muscle fatigue is reached, lifting light weights and lifting heavy weights result in the same amount of muscle growth.
High-load resistance training produces greater gains in maximal strength than low-load training because the nervous system adapts most effectively when training closely resembles the movement used to test strength, whereas muscle growth occurs similarly regardless of load.
When people lift heavy weights (over 60% of their maximum) to muscle failure, they gain more maximum strength than when they lift lighter weights (60% or less) to muscle failure.
Resistance training with light weights and resistance training with heavy weights produce the same amount of muscle growth when both are done until muscle fatigue is reached.
When lifting weights, reaching muscular failure produces the same muscle growth whether using light or heavy weights, because the level of effort matters more than the weight used.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.