Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Changes in measured values
| Pre | 2w | 4w | Pre-2w | Pre-4w | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Mean | 95% CI | Mean | 95% CI | Mean | 95% CI | t | p value | t | p value | |
| Young’s modulus of the rectus femoris muscle (kPa) | 35.6 | 31.0–40.2 | 29.5 | 24.9–34.1 | 28.0 | 23.4–32.6 | −4.028 | 0.0004* | −5.027 | <0.0001* |
| Young’s modulus of the patellar tendon (kPa) | 162.9 | 118.0–207.8 | 144.8 | 99.9–189.7 | 143.9 | 99.0–188.8 | −1.354 | 0.1864 | −1.422 | 0.1660 |
| Knee-flexion range of motion (°) | 122.6 | 113.9–131.4 | 130.3 | 121.5–139.0 | 137.5 | 128.7–146.2 | 4.118 | 0.0003* | 7.986 | <0.0001* |
Physical characteristics of the participants
| Physical characteristics | Participants (n = 15) |
|---|---|
| Age (years) | 26.4 ± 2.2a |
| Height (m) | 1.73 ± 0.03a |
| Body weight (kg) | 66.0 ± 6.9a |
| BMI (kg/m2) | 22.0 ± 1.9a |
Effect of the Young’s modulus and stretching duration on the kneeflexion range of motion
| Model 1 | Model 2 | |||
|---|---|---|---|---|
| t | p value | t | p value | |
| Intercept | 17.284 | <0.0001* | 16.795 | <0.0001* |
| Time (4w) | 4.483 | <0.0001* | 3.393 | 0.0016* |
| Time (2w) | 1.938 | 0.0597 | 0.866 | 0.3918 |
| Time (pre) | – | – | ||
| Young’s modulus of the rectus femoris muscle | −2.402 | 0.0210* | −2.345 | 0.0242* |
| Young’s modulus of the patellar tendon | −0.777 | 0.4419 | – | |
| Young’s modulus of the rectus femoris muscle*Time (4w) | – | −2.041 | 0.0481* | |
| Young’s modulus of the rectus femoris muscle*Time (2w) | – | −0.195 | 0.8461 | |
| Young’s modulus of the rectus femoris muscle*Time (pre) | – | – | ||
| AICC | 314.626 | 307.634 | ||
| BIC | 317.679 | 310.628 | ||