Table 2.
Muscle fiber characteristics and structural properties
| Pre | LL-RE | LL-BFR | P Value | |
|---|---|---|---|---|
| Fiber type, % | ||||
| Type I | 57 (45, 69) | 57 (50, 64) | 52 (43, 62) | 0.6 |
| Type II | 43 (31, 55) | 43 (36, 50) | 47 (38, 57) | 0.6 |
| Fiber CSA, µm2 | ||||
| Type I | 4,393 (3,659, 5,127) | 5,088 (4,192, 5,985) | 4,838 (4,034, 5,642) | 0.116 |
| Type II | 5,770 (4,762, 6,778) | 6,291 (4,984, 7,599) | 6,280 (5,086, 7,475) | 0.5 |
| Fiber perimeter, µm | ||||
| Type I | 261 (238, 284) | 281 (254, 306) | 273 (250, 296) | 0.14 |
| Type II | 299 (272, 327) | 309 (277, 342) | 313 (281, 343) | 0.5 |
| Sharing factor | ||||
| Type I | 2.70 (2.64, 2.78) | 2.67 (2.55, 2,79) | 2.69 (2.62, 2.77) | 0.7 |
| Type II | 2.73 (2.64, 2.82) | 2.69 (2.58, 2.81) | 2.68 (2.62, 2.73) | 0.8 |
| Myonuclei | ||||
| Type I | 2.17 (1.89, 2.45) | 2.33 (1.83, 2.82) | 2.17 (1.83, 2.50) | 0.7 |
| Type II | 2.80 (2.59, 2.99) | 2.83 (2.20, 3.47) | 2.73 (2.33, 3.13) | 0.9 |
| Myonuclear domain, µm2 | ||||
| Type I | 2,369 (1,813, 2,924) | 2,671 (2,293, 3,049) | 2,701 (2,085, 3,317) | 0.4 |
| Type II | 2,594 (1,977, 3,210) | 2,668 (2,158, 3,177) | 2,947 (2,220, 3,673) | 0.6 |
Values are means (95% confidence interval); n = 9/group, except for myonuclei (n = 7/group). LL-RE, low-load resistance exercise; LL-BFR, low-load blood flow restriction resistance exercise; CSA, cross-sectional area.