Lifting Light or Heavy Weights — Which Builds Muscle Better?
Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
If you lift weights until you can't do another rep, it doesn't matter if you use light or heavy weights — you'll grow your muscles about the same. But if you want to get stronger, heavier weights work better. Newbies grow muscle faster than experienced lifters, and doing more workouts helps experienced people grow more. Men get stronger than women with heavy lifting.
Surprising Findings
Older studies reported much larger strength gains than newer ones.
People assume science gets more extreme over time—but here, better methods (blinding, randomization) reduced inflated results. Earlier studies likely overestimated benefits due to bias.
Practical Takeaways
If you want to build muscle: use any load you like—light, medium, or heavy—as long as you push each set to failure.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
If you lift weights until you can't do another rep, it doesn't matter if you use light or heavy weights — you'll grow your muscles about the same. But if you want to get stronger, heavier weights work better. Newbies grow muscle faster than experienced lifters, and doing more workouts helps experienced people grow more. Men get stronger than women with heavy lifting.
Surprising Findings
Older studies reported much larger strength gains than newer ones.
People assume science gets more extreme over time—but here, better methods (blinding, randomization) reduced inflated results. Earlier studies likely overestimated benefits due to bias.
Practical Takeaways
If you want to build muscle: use any load you like—light, medium, or heavy—as long as you push each set to failure.
Publication
Journal
Medicine and Science in Sports and Exercise
Year
2020
Authors
P. Lopez, R. Radaelli, D. Taaffe, R. Newton, D. Galvão, G. Trajano, J. Teodoro, W. Kraemer, K. Häkkinen, R. Pinto
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Claims (6)
Whether you lift light weights with lots of reps or heavy weights with few reps—so long as you push until you can’t do another rep—you’ll build muscle about the same amount.
People who’ve never lifted weights before gain muscle much faster than those who’ve trained before—even if they do the same workout.
If you’ve been lifting for a while, doing more workouts over time will help you build more muscle than just lifting heavier weights.
Lifting heavier weights (fewer reps) leads to bigger strength gains than lifting lighter weights (more reps), even if both are done until exhaustion.
Older studies showed bigger strength gains from weight training than newer ones, probably because today’s studies are better designed and less biased.