The Study
Resistance training, but not leucine, increased basal muscle protein synthesis and reversed frailty in older women consuming optimized protein intake.
This study is like a fair test where two groups of older women did the same workout, but one group took a special powder and the other took a fake powder that looked the same. The results showed that the workout made their muscles stronger and less frail, no matter which powder they took. So we can say the workout caused the improvement, but we can't say the powder did anything extra.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Older women who were weak or getting weaker did 12 weeks of weight training and ate enough protein every day. Some took extra leucine pills, others took dummy pills.
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 572 / 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 — this means older women can become stronger, move better, and escape frailty just by lifting weights and eating enough protein — no expensive supplements needed.
- 2Those who lifted weights and ate enough protein got 47% more muscle protein made at rest, their muscle fibers grew bigger (type I by 16%, type IIa by 28%), they gained 2% more lean mass, and 64% fewer of their frailty signs disappeared.
- 3The leucine pills didn't help at all.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
GeroScience
Year
2025
Authors
K. Jacob, G. Hajj-Boutros, V. Sonjak, J. Leduc‐Gaudet, Felipe Broering, C. Flynn, S. Chevalier, M. Lamarche, Sabah Hussain, José A. Morais
Related Content
Claims (7)
Resistance training increases the effectiveness of dietary protein in preserving muscle mass and supporting physical function.
In frail and pre-frail older women, resistance training raises muscle protein synthesis by 47% when the body is at rest after fasting, but does not increase muscle protein synthesis after eating.
In frail and pre-frail older women, resistance training leads to a 16% increase in the size of type I muscle fibers.
In older women who already eat enough protein and do resistance training, taking extra leucine supplements does not improve muscle protein synthesis, muscle growth, lean mass, or reduce frailty.
In frail and pre-frail older women, 12 weeks of progressive resistance training with 1.2 grams of protein per kilogram of body weight per day increases muscle protein synthesis, enlarges type I and IIa muscle fibers, increases total lean mass by 2%, and reduces frailty status.
In frail older adults, resistance training is required to realize the muscle and functional health benefits from dietary protein; taking protein supplements without resistance training does not improve strength, muscle mass, or physical performance unless their usual protein intake is less than 0.8 grams per kilogram of body weight per day.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.