Table 6.
Correlation between stiffness, force, and EMG.
| r [ ] | Stiffness | Force |
|---|---|---|
| EMGFDP | 0.53 ± 0.25 | 0.32 ± 0.31 |
| EMGFDS | 0.55 ± 0.20 | 0.45 ± 0.33 |
| EMGEIP | 0.48 ± 0.30 | 0.38 ± 0.38 |
| EMGED | 0.57 ± 0.25 | 0.52 ± 0.35 |
| EMGFDI | 0.81 ± 0.10 | 0.57 ± 0.14 |
| EMGSDI | 0.76 ± 0.10 | 0.53 ± 0.11 |
| Force | 0.65 ± 0.19 | – |
Mean and SD of correlation coefficients between stiffness, force, and muscular activity across subjects and tasks. By using these values, we conducted a paired t-test on the Fisher-transformed correlation coefficients on whether the correlation of EMG to force and stiffness significantly differs across subjects. The results show that only for the two intrinsic muscles FDI and SDI, the correlation of EMG to stiffness significantly differs in comparison to its correlation to force (p ≤ 0.001).