Table 3.
Muscle Fiber Characteristics of Older Adults in Response to 5 Days Bed Rest in CON and NMES+PRO Groups
| CON (n = 9) | NMES+PRO (n = 9) | |||
|---|---|---|---|---|
| MyHC | PreBR | PostBR | PreBR | PostBR |
| Myofiber CSA (μm2) | ||||
| I* | 4449 ± 478 | 3623 ± 247 | 4257 ± 500 | 3689 ± 446 |
| II | 4069 ± 700 | 3279 ± 207 | 3643 ± 406 | 3274 ± 276 |
| Pooled* | 4324 ± 535 | 3411 ± 142 | 3994 ± 401 | 3493 ± 389 |
| % Change | % Change | |||
|---|---|---|---|---|
| Myofiber CSA % change (post-pre) | ||||
| I | −26.3 ± 17.2 | −18.3 ± 10.1 | ||
| II | −19.6 ± 12.0 | −10.9 ± 6.8 | ||
| Pooled | −25.6 ± 16.4 | −16.6 ± 8.3 | ||
| % Fiber (number) | ||||
| I | 52.8 ± 4.1 | 47.4 ± 5.5 | 48.7 ± 5.1 | 47.0 ± 4.3 |
| II | 47.2 ± 4.1 | 52.6 ± 5.5 | 51.3 ± 5.1 | 53.0 ± 4.3 |
| Myonuclei/myofiber | ||||
| I# | 2.7 ± 0.1 | 2.5 ± 0.2 | 2.6 ± 0.1 | 2.4 ± 0.2 |
| II | 2.5 ± 0.1 | 2.3 ± 0.1 | 2.7 ± 0.4 | 2.3 ± 0.2 |
| Pooled# | 2.6 ± 0.1 | 2.4 ± 0.2 | 2.6 ± 0.3 | 2.4 ± 0.2 |
| Myonuclear domain (μm2/myonuclei) | ||||
| I | 1612 ± 130 | 1540 ± 168 | 1636 ± 195 | 1528 ± 128 |
| II | 1680 ± 287 | 1417 ± 84 | 1442 ± 146 | 1461 ± 129 |
| Pooled | 1661 ± 176 | 1459 ± 95 | 1566 ± 158 | 1496 ± 130 |
| SC content/myofiber | ||||
| I* | 0.092 ± 0.008 | 0.057 ± 0.015 | 0.083 ± 0.019 | 0.057 ± 0.008 |
| II | 0.076 ± 0.007 | 0.060 ± 0.013 | 0.062 ± 0.011 | 0.054 ± 0.008 |
| Pooled* | 0.085 ± 0.005 | 0.06 ± 0.01 | 0.074 ± 0.014 | 0.056 ± 0.007 |
Data are reported as mean ± SE. A histochemical sample for one subject was not obtained while a methodological issue occurred on another histochemical sample. Therefore, data are n = 9 in each group.
*
Different as a result of bed rest (p < 0.05).
#
Different as a result of bed rest (p ≤ 0.08).