The Study
Does initial skeletal muscle size or sex affect the magnitude of muscle loss in response to 14 days immobilization?
This study looked at whether people who started with bigger muscles lost more muscle when their leg was stuck in a brace for two weeks. It found that, overall, starting muscle size didn’t predict how much muscle was lost—but in a tiny group of 9 women, it seemed like it might. That’s like noticing one red car in a parking lot is scratched—it doesn’t mean all red cars get scratched.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Scientists put people's legs in braces for two weeks to see if people with bigger muscles lost more muscle — and found it depends on whether you're a man or a woman.
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 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — if you're a woman with strong legs and get injured, you might lose more muscle than expected, even if you eat enough protein.
- 2Everyone lost about 10% of their quadriceps muscle and 4% of leg muscle mass.
- 3Women with bigger muscles at the start lost even more.
- 4Men didn't show this pattern.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme
Year
2023
Authors
Vernon G. Coffey, C. McGlory, S. Phillips, Thomas M. Doering
Related Content
Claims (6)
When humans are immobilized for 14 days, their muscle volume decreases by 2-3%.
Keeping one leg immobilized in a knee brace at 60° flexion for 14 days results in a 9.6% decrease in quadriceps muscle size and a 4.1% decrease in leg fat-free mass in healthy young adults.
In healthy young adults who exercise recreationally, the size of their leg muscles before immobilization does not determine how much muscle they lose after 14 days of leg immobilization.
Young women with more muscle mass in their legs before immobilization lose more muscle during 14 days of leg immobilization compared to those with less muscle mass.
After 14 days of muscle immobilization, women with larger muscles at the start lose more muscle mass relative to their starting size than women with smaller muscles, while men show no consistent relationship between their starting muscle size and how much muscle they lose.
When men and women consume standardized amounts of protein during two weeks of muscle immobilization, women with larger initial muscle size still experience more atrophy than men with similar muscle size, regardless of protein intake.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.