Table 6. Comparison of muscle fiber characteristics between muscle architecture types.
| Traits | Muscle fiber type | Parallel | Pennate | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fan-shaped | Fusiform | Strap | Mean | (PE) | Unipennate | Bipennate | Multipennate | Mean | (PE) | ||
| Cross-sectional area (μm2) | I | 4,095.2 | 3,103.1 | 3,941.3 | 3,468.2x | (233.7) | 2,028.1c | 2,711.1b | 3,209.8a | 2,742.2y | (190.2) |
| IIA | 3,936.8a | 2,578.5b | 3,101.4ab | 2,864.6x | (274.3) | 1,504.7c | 2,004.7b | 2,730.8a | 2,165.8y | (171.6) | |
| IIAX | 4,462.2a | 2,227.1c | 3,311.6b | 2,652.5 | (308.7) | nd | 1,754.0b | 2,703.4a | 2,050.7 | (173.8) | |
| IIX | 4,042.9 | 2,994.4 | 3,817.3 | 3,339.1x | (256.0) | 1,906.9c | 2,706.0b | 2,913.9a | 2,627.6y | (245.8) | |
| IIXB | 2,967.6 | 3,418.7 | 3,497.2 | 3,386.0x | (263.5) | 1,908.9b | 2,372.1b | 3,052.2a | 2,548.1y | (223.3) | |
| IIB | 3,897.4a | 3,248.3b | 2,932.3b | 3,237.8 | (221.4) | 2,163.8b | 2,856.2a | 3,221.8a | 2,884.6 | (194.1) | |
| Mean | 3,825.6a | 3,056.3b | 3,558.9ab | 3,289.0x | (216.0) | 1,888.4c | 2,448.4b | 3,015.6a | 2,534.5y | (163.5) | |
| Relative fiber area (%) | I | 15.9b | 14.4b | 49.4a | 26.5 | (4.9) | 32.5 | 20.6 | 25.7 | 25.4 | (4.2) |
| IIA | 13.1 | 16.8 | 22.9 | 18.6 | (2.3) | 27.0a | 18.2b | 20.1b | 21.0 | (2.3) | |
| IIAX | 1.0 | 2.2 | 1.7 | 1.9 | (0.7) | nd | 1.8 | 1.5 | 1.3 | (0.5) | |
| IIX | 50.6a | 20.4b | 16.1b | 21.3 | (3.9) | 14.6b | 20.8a | 22.9a | 20.1 | (4.0) | |
| IIXB | 9.7 | 16.3 | 7.5 | 12.8 | (4.1) | 10.2 | 13.3 | 12.5 | 12.3 | (2.4) | |
| IIB | 9.7b | 29.8a | 2.4b | 18.8 | (5.3) | 15.7 | 25.2 | 17.2 | 19.9 | (4.9) | |
| Fiber density (number/mm2) | I | 38.9b | 47.3b | 129.8a | 74.9 | (13.0) | 159.2a | 72.3b | 76.2b | 94.1 | (16.6) |
| IIA | 32.9b | 67.5a | 76.4a | 67.8y | (7.8) | 173.9a | 92.1b | 75.2b | 104.8x | (13.7) | |
| IIAX | 2.2 | 10.4 | 5.3 | 8.0 | (2.7) | nd | 10.2 | 5.9 | 6.1 | (2.5) | |
| IIX | 128.7a | 77.0b | 39.2b | 68.1 | (12.5) | 79.1 | 78.7 | 71.2 | 75.9 | (14.9) | |
| IIXB | 33.1 | 47.6 | 22.4 | 37.9 | (11.7) | 53.2 | 51.5 | 43.2 | 48.7 | (9.2) | |
| IIB | 26.1b | 96.8a | 7.2b | 60.6 | (16.6) | 83.1 | 87.8 | 55.1 | 74.2 | (19.3) | |
| Total | 261.9 | 346.9 | 280.3 | 317.4y | (21.4) | 548.5a | 393.5b | 326.7c | 404.2x | (26.4) | |
Data are means and pooled SE (PE).
a–b,x,y
Significant differences (p<0.05) between the subtypes within the same architecture and between parallel and pennate types are indicated with different superscripts, respectively.
nd, not detected.