The Study
Myofibrillar protein synthesis in young and old human subjects after three months of resistance training.
This study just looked at how much muscle protein people made before and after lifting weights, but we don’t know if they were randomly assigned or if the scientists tried to avoid bias. So we can’t say the weights caused any changes — we only saw a pattern.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Older adults' muscles make new protein slower than young adults', even when they lift weights.
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 537 / 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.
- 1Even with strength gains from training, older muscles still build protein much slower — suggesting aging itself, not lack of use, is the main cause.
- 2Older adults had 33% slower muscle protein building than young adults at start.
- 3After 3 months of weight training, it was still 27% slower — and didn't get faster in either group.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The American journal of physiology
Year
1995
Authors
S. Welle, C. Thornton, M. Statt
Related Content
Claims (3)
In healthy adults, muscle protein synthesis is 33% slower in people aged 62 to 72 than in people aged 22 to 31, based on measurements of leucine incorporation into muscle proteins.
After resistance training, younger people experienced a 10% increase in overall protein turnover, while older people did not. The rate of muscle breakdown, measured by a specific urinary marker, did not change in either group.
Three months of progressive resistance training did not increase myofibrillar protein synthesis in young or older adults, and older adults still had a 27% lower rate of synthesis compared to young adults.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.