The Study
Relationship of Physical Function to Single Muscle Fiber Contractility in Older Adults: Effects of Resistance Training With and Without Caloric Restriction
This study compared two ways of getting stronger as you get older: lifting weights alone, or lifting weights while eating less. It found that both ways helped muscles work better, but eating less didn’t make them work any better than just lifting weights. It didn’t prove that eating less causes better muscles — it just showed that adding it didn’t help more.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Older adults who lifted weights got stronger muscles. Those who also ate less didn’t get any extra muscle strength from dieting.
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 574 / 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 — lifting weights alone was enough to improve muscle quality; cutting calories didn’t help more, even though people lost more fat.
- 2After 5 months, both groups improved muscle fiber force by 16–26% (normalized force).
- 3Fat loss was greater in the dieting group, but muscle fiber gains were the same.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journals of Gerontology: Series A
Year
2019
Authors
Zhong‐Min Wang, X. Leng, M. L. Messi, Seung-Jun Choi, A. Marsh, B. Nicklas, O. Delbono
Related Content
Claims (6)
People who do resistance training while eating fewer calories gain more muscular strength than people who eat fewer calories without resistance training.
In adults aged 65 to 80 who are overweight or obese, five months of progressive resistance training increases the contractile force of individual muscle fibers and improves knee extensor function in both slow-twitch and fast-twitch muscle fibers, whether or not calorie intake is reduced.
In older adults who are overweight or obese, adding moderate calorie reduction to strength training does not lead to greater improvements in muscle fiber strength or knee muscle function than strength training by itself.
In older overweight adults doing strength training while eating fewer calories, faster walking speed is associated with larger slow-twitch muscle fibers.
In older adults who are overweight and doing strength training while eating fewer calories, greater improvements in the strength of slow-twitch muscle fibers are linked to greater decreases in fat stored between muscles.
In older adults who are overweight and doing strength training, losing fat from the thighs is linked to stronger performance of fast-twitch muscle fibers.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.