The Study
Heavy resistance exercise training in older men: A responder and inter-individual variability analysis
This study is like a fair test where half the guys did heavy lifting and half didn’t, and the ones who lifted got stronger and bigger — and we know it was because of the lifting, not luck. But we only tested healthy older men, so we can’t say it works the same for everyone.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Older men who lifted heavy weights three times a week got stronger and their muscles grew — but not everyone gained the same amount.
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 562 / 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 — almost all older men benefit significantly, so lifting weights is highly recommended regardless of initial fitness.
- 2On average, strength went up 19%, muscle fibers grew 14%.
- 382% of men were great responders, only 5% barely improved.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
PLOS One
Year
2025
Authors
Casper Soendenbroe, J. L. Andersen, M. F. Heisterberg, Michael Kjaer, A. Mackey
Related Content
Claims (6)
When people who’ve never lifted weights before start training, some gain just a little muscle—like half a kilo—while others gain a lot, up to three kilos, in about two to three months.
Older men who start out weaker or with smaller fast-twitch muscle fibers tend to get bigger gains from heavy weight training, but even knowing how weak they were at the start doesn’t fully explain why some people improve more than others.
When older men do heavy weight training, some get much stronger and build more muscle than others—even when they do the same workout—and those differences are bigger than any mistakes we might make when measuring them.
When older men who are healthy lift heavy weights for 16 weeks, most of them—82%—get much stronger and build more muscle, while barely 5% don’t improve much, so it’s rare for someone to not benefit at all.
If older men in their early 70s lift heavy weights three times a week for four months, they’ll get noticeably stronger and their big muscle fibers will grow bigger.
When older men get stronger quickly at the start of weight training, it’s often just because they’re learning how to lift better—not because their muscles are growing or getting stronger for real. So, early gains don’t mean they’ll keep getting stronger over time.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.