Logistic regression model features
| Feature | Definition |
| Target stress (σ) | The peak compressive stress in the tissue measured in MPa induced by the pin plate’s compression of that tissue at the target load. |
| Target duration | The length of time in seconds in which the indentation pin holds its end position in contact with the tissue, measured in seconds. |
| Compression duration | The length of time in seconds in which the tissue is being actively compressed before the target stress is reached. |
| Contact stiffness | The lowest measured stiffness (MPa) which occurs at initial contact, where stiffness is defined as stress/strain. |
| Target stiffness | The maximum measured stiffness (MPa) which occurs when the target stress is achieved, where stiffness is defined as stress/strain. |
| Relaxation stress | The decrease in stress on the tissue (in MPa) as the indentation pin holds its position and tissue components such as fluids shift causing a dynamic reduction in stiffness. |
| Initial thickness | The initial contact thickness of the tissue in mm. |
| Target strain (ε) | The peak compressive strain (per cent deformation) that the indentation pin induces in the tissue relative to its initial thickness. |