TABLE 2.
Associations of skeletal muscle mitochondrial energetics and Pittsburgh Performance Fatigability Index (PPFI) in older adults in the Study of Muscle, Mobility and Aging a .
| Model 1 | Model 2 | Model 3 | ||||
|---|---|---|---|---|---|---|
| β (95% CI) | Partial R 2 | β (95% CI) | Partial R 2 | β (95% CI) | Partial R 2 | |
| Max OXPHOS (1 SD = 18.4 pmol/(s × mg); n = 688) | 0.65 (0.35, 0.94) | 0.04 | 0.60 (0.30, 0.89) | 0.04 | 0.55 (0.26, 0.84) | 0.04 |
| Max ETS (1 SD = 22.1 pmol/(s × mg); n = 562) | 0.48 (0.17, 0.79) | 0.23 | 0.43 (0.12, 0.74) | 0.22 | 0.39 (0.09, 0.70) | 0.22 |
| ATPmax (1 SD = 0.15 mM/s; n = 742) | 0.66 (0.39, 0.93) | 0.06 | 0.65 (0.38, 0.92) | 0.06 | 0.54 (0.27, 0.81) | 0.06 |
Abbreviations: ATP, adenosine triphosphate; ETS, electronic transfer system; OXPHOS, oxidative phosphorylation; PPFI, Pittsburgh Performance Fatigability Index.
a
Model 1 adjusted for technician/site, age, sex, race; Model 2 further adjusted for height and weight on top of Model 1; Model 3 additionally adjusted for total activity count from wrist‐worn ActiGraph GT9X.