The Study
The effect of training volume and intensity on improvements in muscular strength and size in resistance-trained men
This study is like a fair race where people were randomly put into two different workout groups. Because it was fair and controlled, we can say one type of workout probably caused better arm strength and muscle growth in trained guys over 8 weeks.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Some people lift heavy weights with few reps, others lift lighter weights with more reps. This study checked which way builds more muscle and strength in guys who already lift.
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 554 / 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.
- 1The heavy-lift group made noticeably better gains in upper body strength and muscle, which matters for real-world training outcomes.
- 2The heavy-lift group gained 5.2% more arm muscle and got 14.8% stronger in bench press.
- 3The high-rep group gained 2.2% arm muscle and got 6.9% stronger.
- 4Leg strength improved the same in both.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Physiological Reports
Year
2015
Authors
G. Mangine, J. Hoffman, Adam M. Gonzalez, Jeremy R. Townsend, Adam J. Wells, Adam R. Jajtner, Kyle S Beyer, Carleigh H. Boone, Amelia A. Miramonti, Ran Wang, Michael B Lamonica, D. Fukuda, N. Ratamess, Jeffrey R Stout
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Claims (6)
The more you lift each week for a specific muscle, the more it grows—but after a point, doing even more doesn't help much.
In guys who lift weights regularly, doing more reps with lighter weights and short breaks gives a bigger boost in growth hormone early on (by week 3) than doing fewer reps with heavier weights and longer breaks—but by week 10, that difference goes away.
If you're a guy who lifts weights, doing more reps with lighter weights (which spikes your hormones more) doesn't build more muscle or strength over 8 weeks than lifting heavier weights with fewer reps—even though the hormone changes look different.
If you're a guy who's already been lifting weights, doing fewer reps with heavier weights and longer rests might build more arm muscle over 8 weeks than doing more reps with lighter weights and shorter breaks.
If you're a guy who's already used to lifting weights, doing fewer reps with heavier weights and longer rests might boost your bench press more than doing lots of reps with lighter weights and short breaks — at least over 8 weeks.
If you're a guy who's already used to lifting weights, doing heavy sets with long rests works just as well as doing more reps with shorter breaks when it comes to getting stronger in the squat after 8 weeks.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.