Table 2.
Main Effects of Age and Training on Neuromuscular Junctions in the Lateral Thyroarytenoid Muscle
| Young | Old | Control | Trained | |
|---|---|---|---|---|
| Presynaptic remodelling | ||||
| Axon withdrawal (%) | 39.9±4.6 | 40.9±5.2 | 37.9±4.2 | 43.0±5.5 |
| Axon sprouts (%)* | 2.3±0.8 | 9.0±2.3† | 4.4±1.7 | 6.9±2.0 |
| Terminal Schwann cell processes (%) | 14.3±2.5 | 19.9±3.7 | 17.6±3.2 | 16.7±3.3 |
| Size and pre/postrelationship | ||||
| Nerve terminal volume (µm3) | 76.6±8.9 | 74.4±9.5 | 63.4±7.3 | 87.6±10.0 |
| Motor endplate volume (µm3) | 224.4±8.5 | 247.9±8.4 | 230.1±11.1 | 242.3±5.6 |
| Overlap (%) | 33.9±4.3 | 34.3±4.7 | 33.1±4.1 | 35.1±4.9 |
| Endplate stability | ||||
| Dispersion (%)‡ | 10.9±0.5 | 13.5±0.7§ | 12.4±0.9 | 11.9±0.4§ |
| Fragmented endplates (%)‡ | 11.6±1.4 | 28.7±2.5† | 20.7±3.2 | 19.6±2.4 |
Notes: Values are means ± SE; n = 40 (20 per group).
*Nonparametric testing completed due to heteroskedasticity.
†Significant difference (p ≤ .05) from young group.
‡Log transformed to achieve homoskedasticity; values shown untransformed.
§Significant interaction (p ≤ .05) between age and training.