The Study
Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men
This study is like a fair race between two groups of guys who lifted weights differently — one used light weights with lots of reps, the other used heavy weights with fewer reps. Both groups got stronger and bigger muscles about the same, so we can say the weight you lift doesn’t matter as long as you go all the way to failure. But it doesn’t mean lifting heavy is useless — it just didn’t beat light weights here.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
When people who already lift weights train until they can't do another rep, it doesn't matter if they use light or heavy weights — they grow muscles and get stronger the same way.
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 561 / 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 — you can build muscle and strength with lighter weights if you train hard enough, which makes workouts more flexible and accessible.
- 2Both groups grew muscle fibers and lean mass by about the same amount.
- 3Bench press strength went up more with heavy weights (+14 kg vs +9 kg).
- 4Hormones like testosterone didn't predict gains.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Applied Physiology
Year
2016
Authors
Robert W Morton, Sara Y Oikawa, C. Wavell, N. Mazara, C. McGlory, J. Quadrilatero, Brittany L. Baechler, S. Baker, Stuart M Phillips
Related Content
Videos (2)
Claims (10)
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.
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.
Whether you lift lighter weights or heavier weights until you can't do any more reps, both ways give you the same muscle growth and strength gains if you're already used to training.
If you lift light weights for more reps or heavy weights for fewer reps—but do the same total amount of work—you’ll grow your muscles just as much either way.
If you push your muscles as hard as you can until you can't do any more reps, that's what really makes them grow bigger. It doesn't matter how many reps you do, as long as you're giving your absolute best effort.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.