Heavy or Light Weights? Both Can Grow Muscles the Same Way
The Effects of Low-Load Vs. High-Load Resistance Training on Muscle Fiber Hypertrophy: A Meta-Analysis
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Low-load training may be just as effective as high-load for muscle fiber growth—despite decades of advice saying heavy weights are essential.
Most fitness culture, textbooks, and even ACSM guidelines promote 70–85% 1RM as optimal for hypertrophy. This study says: maybe not—if you go to failure.
Practical Takeaways
If you hate heavy lifting or have joint issues, try training with lighter weights (40–60% 1RM) taken to failure—your quads might grow just as well.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Low-load training may be just as effective as high-load for muscle fiber growth—despite decades of advice saying heavy weights are essential.
Most fitness culture, textbooks, and even ACSM guidelines promote 70–85% 1RM as optimal for hypertrophy. This study says: maybe not—if you go to failure.
Practical Takeaways
If you hate heavy lifting or have joint issues, try training with lighter weights (40–60% 1RM) taken to failure—your quads might grow just as well.
Publication
Journal
Journal of Human Kinetics
Year
2020
Authors
J. Grgic
Related Content
Claims (10)
We can’t say whether light or heavy weights are better for growing muscle fibers in the thighs — we just don’t have enough good data yet, and we need more studies with more people.
We don’t know if most people actually stuck to their workout plans — only one study checked, so we can’t be sure the results reflect what really happened during training.
Even if you lift light weights, if you go until you can’t do another rep, your muscles end up using almost all the same fibers as if you lifted heavy — which might be why both ways make muscles grow similarly.
Only five small studies were used, with just 120 people total — so the results are too shaky to be very confident about.
Whether you lift light weights or heavy weights until you can't do another rep, your slow-twitch muscle fibers in your thighs grow about the same amount — but we can't be sure because the results are too uncertain.