Table 3.
Volumes of muscle components and concentration conversion factors for human muscle
| Component | Relative volume (% fiber volume) | Comments |
|---|---|---|
| SR | 3.8 | Eisenberg (1983) |
| Mitochondria | 5 | Eisenberg (1983) |
| t-system | 0.28 | Eisenberg (1983) |
| JS | 0.014 | Estimated to be 5% of t-system volume (see text) |
| Myoplasmic water | 69 | Fraction of water in whole tissue that is inside fibers, excluding volumes occupied by SR, t-system, and JS |
| Concentration conversion factors | ||
| Whole muscle (kg−1) → fiber (liter−1) | 1.18 | |
| Whole muscle (kg−1) → myoplasmic water (liter−1) | 1.45 | |
| Fiber (liter−1) → myoplasmic water (liter−1) | 1.23 | |
Other values required for calculations: whole muscle density, 1.05 kg liter−1 (Segal et al., 1986) and protein density, 1.37 kg liter−1 (Fischer et al., 2004; these values give ratio of wet mass/dry mass of whole muscle = 5); extracellular water, 12.5% of total muscle water (Sjogaard et al., 1985).