Table 1.
Morphological and mechanical properties of muscles for plyometric and isometric training protocols [mean (SD)]
| Plyometric training | Isometric training | |||
|---|---|---|---|---|
| Before | After | Before | After | |
| MVC (Nm) | 103.3 (7.6) | 107.3 (9.4)* | 104.3 (16.7) | 124.8 (15.0)*** |
| Muscle thickness of MG (mm) | 17.7 (1.7) | 18.8 (2.2)** | 18.1 (1.8) | 19.0 (1.9)*** |
| Muscle thickness of LG (mm) | 16.0 (2.3) | 16.9 (2.4)** | 15.5 (2.5) | 16.4 (2.6)** |
| Muscle thickness of SOL (mm) | 15.3 (2.5) | 16.1 (2.4)*** | 15.9 (1.9) | 16.8 (2.4)** |
| Muscle thickness of PF (mm) | 16.3 (1.5) | 17.3 (1.6)*** | 16.5 (1.7) | 17.4 (1.9)*** |
| Active muscle stiffness at 30%MVC (N·mm−1) | 32.3 (8.6) | 44.6 (9.6)** | 35.9 (10.7) | 40.3 (8.1) |
| Active muscle stiffness at 50%MVC (N·mm−1) | 48.2 (15.5) | 77.0 (24.3)** | 49.4 (14.2) | 60.4 (18.5) |
| Active muscle stiffness at 70%MVC (N·mm−1) | 63.9 (17.8) | 108.4 (16.7)*** | 72.4 (16.8) | 89.5 (27.4) |
| Passive muscle stiffness (N·mm−) | 7.35 (3.30) | 7.30 (1.86) | 7.39 (3.09) | 7.47 (2.17) |
Significantly different from before (*P < 0.05, **P < 0.01, ***P < 0.001). MVC, maximum voluntary contraction; MG, medial gastrocnemius muscle; LG, lateral gastrocnemius muscle; SOL, soleus muscle, PF, plantar flexor muscles.